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Get your Future-Proof VCE Chemistry Formula Book for just $55

James Kennedy's VCE Chemistry Formula Book 2017-2021Inspired by the formula booklets used by VCE Physics and VCE Maths Methods, here’s an 8-page Chemistry formula booklet you can use for your Year 11 and 12 Chemistry assignments. This custom-made booklet is a collection of reliable formulae that I have been using to answer VCE Chemistry questions while teaching and tutoring around Melbourne.

There are 76 formulae on 8 pages. At least 10 of these formulae aren’t in the three main chemistry textbooks. Orders are shipped in A4-sized booklet that resembles the VCAA Data Booklet.

Orders from schools, students and tutors are all welcome. Price includes free international delivery and a 10% voucher for the T-shirt store.

Order your copy now by clicking here

Learn from the best

James Kennedy achieved outstanding A-level results in 2006 in Maths, Chemistry, Physics and Biology. Those excellent grades (which equate to an ATAR of 99+) earned him a BA (Hons) degree and a Masters degree in Natural Sciences from the University of Cambridge.

Shortcut formulae were just one of the techniques James used to pass his A-level exams and get into Cambridge. Along with structured revision, revision guides, practice papers and study notes on wall-cards, James used shortcut formulae to save precious time in the examination hall. You can get your own copy of these original shortcut formulae – revised and updated for the 2017-2021 VCE Chemistry course – for just $55 including free international shipping. Click here to get your copy.

Here’s an preview of the inside

VCE Chemistry Formula Booklet, $55. Free, Fast Delivery Included.
VCE Chemistry Formula Booklet, $55. Free, Fast Delivery Included.

Click here to purchase your 8-page companion book with 76 formulae relevant for VCE Chemistry Units 1-4

Let’s add oxygen, fluorine and neon gases

Oxygen from Theodore Gray's amazing book, The Elements
Oxygen from Theodore Gray’s amazing book, The Elements

This post concludes the Periodic Table Smoothie experiment.

Recall that we’ve just finished adding one mole of nitrogen gas and created a bizarre boron polymer at the bottom of our vessel. The temperature was 350 °C and the pressure in our vessel was 891 kPa.

Today, we’re going to add 1.00 mole of oxygen gas, stand back and observe.

Nothing happens.

This is disappointing news.

Many of the substances in our vessel react (more accurately, explode) in the presence of oxygen but the ignition temperature for all of those explosions to take place is at least 500 °C. The temperature of our vessel is set at just 350 °C. At this temperature, nothing would actually happen.

There’s not enough activation energy to break bonds in the reactant particles in order to get the reaction started. We call this activation energy (EA) in chemistry. If we were to add a source of excessive heat (e.g. a matchstick), the vessel would explode.

Should we heat up the vessel to 500 °C and blow up the experiment right here?

If we did, the following reactions would happen:

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Enough of these reactions – particularly the first three – are sufficiently exothermic to trigger a chain reaction – at least up to the reaction of oxygen with beryllium carbide. The vessel would bang, explode, and shatter. The helium would float away, dangerous lithium amide would fly out sideways, and polyborazine powder, whatever that is, would land on the floor.

Let’s not ignite our experiment – not yet.

Conclusion after adding 1.00 mole of oxygen gas

Substance Amount in mol
He(g) 1.000
Be(s) 0.514
LiH(s) 0.000
Li2C2(s) 0.272
B2H6(g) 0.000
Be2C(s) 0.175
H2(g) 0.007
BeC2(s) 0.136
CH4(g) 0.009
N2(g) 0.552
NH3(g) 0.154
LiNH2(s) 0.277
polyborazine 12.194 grams

Pressure: 891 kPa (higher than before due to the addition of nitrogen gas)
Temperature: 350 °C (vessel is still being maintained at constant temperature)

Oxygen was relatively uneventful. Let’s add fluorine and see what happens.

Let’s add fluorine gas

elements110009
Elements by Theodore Gray

The following three reactions would all occur as 1.00 mole of fluorine gas is added:

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These two products are quite interesting:

  • HF, hydrogen fluoride, an aqueous solution of which was used by Breaking Bad’s Walter White to dissolve evidence (his victims)
  • NF3, nitrogen trifluoride, is used as an etching agent when making printed circuit boards (PCBs)

Let’s add neon gas

elements110010
Elements by Theodore Gray

When 1.00 mole of neon gas is added, the total pressure inside the vessel increases but no reaction occurs. The concentrations of all the other gases present are unaffected.

The End

That concludes our Periodic Table Smoothie experiment. The most interesting conclusion was the discovery of polyborazine, the bizarre solid that collected at the bottom of the vessel.

Also of interest was how easily we created ammonia, one of the simplest of biological compounds, just by mixing elements together. Could the compounds necessary for life be so easy to create that their existence is an inevitable consequence of the Big Bang? Is life inevitable? If the Big Bang were to happen all over again, would life occur? And would it look any different?

Possibly not.

We Lied To You

Click to download the book
click-here

This book contains 50 lies taught in the VCE Chemistry course.

These lies include well-meaning simplifications of the truth, mistakes in the textbook, and, in a few extreme cases, blatant falsehoods.

This book isn’t a criticism of the VCE Chemistry course at all. In fact, I just want to highlight the sheer complexity of Chemistry and the need to make sweeping generalisations at every level so it can be comprehensible to our students. This is a legitimate practice called constructivism in pedagogical circles. (Look that up.)

Many of these ‘lies’ taught at VCE level will be debunked by your first-year chemistry lecturers at university.

Here’s a preview of some of the lies mentioned in the book. Check out all 50 by clicking the download link at the bottom of the page.


lie-2


lie-15


lie-25


we-lied-to-you-cover-lightbulbs

click-here


Chemists need to speak the same language as the public

scientist-clipart-science-clip-art-school1
Chemists and the public need to be speaking the same language

Chemicals

The public uses the word ‘chemical’ to mean ‘synthetic substance’. Chemists have traditionally opposed this definition and stuck with ‘substance’ instead, responding with “everything is a chemical” in defence.

Arguing over definitions is futile and avoids the elephant in the room – that there’s been almost no public outreach to support the field of chemistry in the last few decades to counteract growing public skepticism of science (and of chemistry in particular).

Furthermore, it’s even more futile arguing over definitions when the Oxford English Dictionary provides a clear answer to this debate:

chemical (noun) – a distinct compound or substance, especially one which has been artificially prepared or purified

I ask all chemists to embrace the dictionary definition of ‘chemical’ and stop bickering with the public over definitions.

My main concern here is that if “everything is a chemical”, then it therefore follows that ‘chemophobia’ is the fear of everything, which is nonsensical. If we’re going to talk about chemophobia, we’re also going to have to accept the definition of chemical that the OED and the public have been using for a long time: that “chemical” = “artificially prepared substance”.

So what do we call non-synthetic chemicals? Try using a word with less baggage such as “molecule”, “compound”, “substance” or “element” where it’s relevant. By using these words, we avoid the natural=good/artificial=bad divide, which is the central assumption of chemophobia.

Chemophobia

‘Chemophobia’ is an irrational aversion to chemicals perceived as synthetic.

The word ‘chemophobia’ refers to a small subset of people who are not only disenfranchised by science, but who have subscribed to alternative sources of knowledge (either ancient wisdom or – sadly – Google). Many people with chemophobia are protesting against the establishment, and this is particularly evident in the anti-GMO movement. At the core of most people who oppose GMOs is a moral/political opposition to having their food supply controlled by giant corporations. No number of scientific studies concluding the safety and reliability of GMO crops will succeed in persuading them otherwise because the anti-GMO movement is founded on moral/political beliefs, not on science. By throwing science at them, we’re wasting our time.

More important than chemophobia

The Royal Society of Chemistry’s recent report on Public Perceptions of Science showed roughly a 20-60-20 range of attitudes towards chemistry.

206020.png

No matter how the RSC phrased the question, roughly 20% of the UK public who were surveyed indicated a negative attitude towards chemistry, and another 20% showed a positive attitude. The 60% in the middle felt disconnected from the subject – maybe disliked it in school – but felt neutral towards it when asked.

Chemophobia afflicts some people in the bottom 20%. They gave negative word-associations with ‘chemistry’ (e.g. ‘accidents’, ‘dangerous’ and ‘inaccessible’).That bottom 20% group is so vocal (e.g. Food Babe) that they distract chemists from the 60% in who are neutral. The ‘neutral’ crowd is a much larger audience that’s much easier to engage/persuade through outreach efforts. We should focus on talking to them.

Neil deGrasse Tyson has said in interviews that his huge TV hit show COSMOS was aimed at “people who didn’t even know they might like science”. That’s the middle 60%. Brian Cox’s amazing Wonders of the Universe was aimed at a similar audience – but chemistry has nothing similar to offer. We’re engaging those who are already interested (with academic talks and specialist journals) and we’re engaging with the bottom 20% via social media and comments on foodbabe.com… but why haven’t we started engaging the middle 60%, who gets most of their science information from TV? How many chemistry TV icons can you name? Where are the multi-channel launches of big-budget chemistry documentaries*? Chemistry is lagging far behind biology and physics in that regard.

*BBC Four’s Chemistry: A Volatile History (2010) doesn’t count – it was only three episodes long, got no further than ‘the elements’ and was presented by a PHYSICIST!

Focus on the 60% who are ‘neutral’

I ask chemists to focus on addressing the disinterested 60%. From an outreach perspective, this is much more fun and is positive rather than reactionary. By engaging those who feel neutral about chemistry, we might even empower enough of the public to fight chemophobia (online, at least) by themselves – without our direct intervention.

I urge chemists to tell the public what you do in simple terms. Describe your work to the public. Tweet about it. Participate in your university/faculty’s YouTube videos by explaining your work and its relevance. Offer advice as a science correspondent for local media outlets (many universities have ‘expert lines’ – get involved). Give your ‘talk’ at local schools – it make a HUGE difference to students’ perceptions of science. Devote 5% of your working time to doing outreach. As a teacher, I’m practically doing it full-time.

Plus, we urgently need a chemistry TV hero. Could someone do that, too, please?

Let’s add nitrogen gas

elements110007
‘Nitrogen’ page from Theodore Gray’s amazing book, ‘The Elements’

Initial conditions

Recall from last week that our Periodic Table Smoothie contains the following species:

Substance Amount present (moles)
He(g) 1.00000
Be(s) 0.51435
LiH(s) 0.27670
Li2C2(s) 0.27165
B2H6(g) 0.23300
Be2C(s) 0.17470
H2(g) 0.14267
BeC2(s) 0.13625
CH4(g) 0.00949

Pressure: 718 kPa
Temperature: 350 °C

Reactions of nitrogen in our 10-litre vessel

Our freshly-added 1.00 mol of nitrogen gas, N2(g), reacts with hydrogen gas to make ammonia in the following reversible (equilibrium) reaction. We will assume that the interior metal surface of the vessel is a suitable catalyst for this reaction (e.g. iron). 

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There are three other reactions below that might have occurred at higher temperature, but I’ve chosen not to raise the temperature of the vessel at this point. Rather, we’ll keep it at 350 °C to keep things manageable.*

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*I was tempted at this point to elevate the temperature of our vessel to 500 °C so that the second reaction could take place as well. This would produce copious amounts of smelly ammonia gas, which would allow for larger quantities of interesting organic compounds to be produced later on. To keep our simulation safe and (relatively) simple, I’ve decided to keep the vessel at 350 °C. Interesting compounds organic will still form – only in smaller amounts.

Equilibria

The ammonia reaction above (the first equation) is actually an equilibrium reaction. That means that the reactants are never completely used up, and the yield is not 100%.

Recall from Le Châtelier’s principle that removing product from an equilibrium reaction causes the position of equilibrium to shift to the right, forming more product. This is because:

“If an equilibrium system is subjected to a change, the system will adjust itself to partially oppose the effect of the change.” – Le Châtelier’s principle

There are three reactions that will remove ammonia from our vessel while it’s being produced, and I’ve put all three of these into the simulation. One of these is the reverse of the reaction above (producing hydrogen and nitrogen gases) and the other two are described below. Let’s take a look at those other two reactions.

With what will the ammonia react in our vessel?

Ammonia can undergo the following reactions with the other things in our vessel**

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**The ammonia does react with methane and beryllium as well, but only at temperatures of 1200 °C and 600 °C, respectively.

Two compounds will be formed: lithium amide and borazine.[1] Lithium amide reacts with nothing else in the vessel, so the reaction chain stops there. Borazine, on the other hand, is much more interesting.

We’ve made borazine!

Borazine is a colourless liquid at room at temperature. It boils at 53 °C and has a structure that resembles that of benzene.

200px-borazine-dimensions-2d
Borazine is isostructural with benzene
Because of the electronegativity difference of about 1.0 between the B and N atoms in the ring, borazine has a mesomer structure:

600px-borazin_mesomers

Like benzene, there is partial delocalisation of the lone pair of electrons on the nitrogen atoms.

Borazine polymerises into polyborazine!

Fascinatingly, borazine polymerises into polyborazine at temperatures above 70 °C, releasing an equal number of moles of hydrogen gas.[2] Polyborazine isn’t particularly well-understood or well-documented, but one recent paper suggested it might play a role in the creation of potential ceramics such as boron carbonitrides. Borazine can also be used as a precursor to grow boron nitride thin films on surfaces, such as the nanomesh structure which is formed on rhodium.[3]

Like several of the other compounds we’ve created in our Periodic Table Smoothie, polyborazine has also been proposed as a hydrogen storage medium for hydrogen cars, whereby polyborazine utilises a “single pot” process for digestion and reduction to recreate ammonia borane.

polyborazylene_polymer
Polyborazine’s chemical structure
The hydrogen released during the polymerisation process will then react further with a little bit of the remaining nitrogen to produce a little more NH3(g) – but not much. Recall from earlier that the ammonia reaction is an equilibrium one, and the yield of NH3(g) at pressures under 30 atmospheres is very low. Pressure in our vessel is still only around 7 atmospheres.

Simulation results

nitrogen smoothie.png

Once polymerised, this would form about 12 grams of polyborazine:

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As far as I’m aware, no further reactions will take place in the vessel this week.

Conclusion after adding 1.00 mole of nitrogen gas

Substance Amount in mol
He(g) 1.000
Be(s) 0.514
LiH(s) 0.000
Li2C2(s) 0.272
B2H6(g) 0.000
Be2C(s) 0.175
H2(g) 0.007
BeC2(s) 0.136
CH4(g) 0.009
N2(g) 0.552
NH3(g) 0.154
LiNH2(s) 0.277
polyborazine 12.194 grams

Pressure: 891 kPa (higher than before due to the addition of nitrogen gas)
Temperature: 350 °C (vessel is still being maintained at constant temperature)

Next week, we’ll add a mole of oxygen gas to the vessel. Warning: it might explode.

References

  1. Stock, Alfred and Erich Pohland. “Borwasserstoffe, VIII. Zur Kenntnis Des B 2 H 6 Und Des B 5 H 11”. Berichte der deutschen chemischen Gesellschaft (A and B Series) 59.9 (1926): 2210-2215. Web.
  2. Mohammad, Faiz. Specialty Polymers. Tunbridge Wells: Anshan, 2007. Print.
  3. Toury, Berangere and Philippe Miele. “A New Polyborazine-Based Route To Boron Nitride Fibres”. Journal of Materials Chemistry 14.17 (2004): 2609. Web. 4 May 2016.

Let’s add carbon (graphite) powder

elements110006
‘Carbon’ page from Theodore Gray’s amazing book: The Elements

Today, we’re going to add 1.00 mole of carbon to our vessel. After adding boron last week, we left our vessel locked at 350 °C and with a pressure of 638 kPa. These reactions are taking place at 350 °C and constant volume (exactly 10 litres). Pressure inside the vessel will therefore change over time.

Allotropes of carbon

Carbon has various allotropes (structural arrangements of an element). Diamond is extremely strong and highly unreactive, while graphite is soft and brittle. The differences are all due to the type of bonding between carbon atoms. In diamond, carbon atoms are bonded by four strong covalent bonds with the surrounding atoms in a strong, hard three-dimensional ‘network lattice’. Graphite owes its softness and brittleness to the fact that its carbon atoms are bonded by only three strong covalent bonds in a two-dimensional ‘layer lattice’. Individual layers are very strong, but the layers can be separated by just the slightest disturbance. Touching graphite lightly onto paper will remove layers of carbon atoms and place them onto the page (such as in a pencil). Using a diamond the same way would likely tear the paper instead.

For this reason, I’m going to put graphite into the vessel instead of diamond. Diamond is so strong and inert that it’s unlikely to do any interesting chemistry in our experiment. Graphite, on the other hand, will.

The following seven chemical reactions will take place after adding carbon (graphite) powder

As soon as the carbon powder enters the vessel, it will begin to react with the following three species as follows:

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The ethyne produced in the third reaction will then react with any lithium and beryllium remaining in the vessel as follows:

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The hydrogen gas produced by the above two reactions will then react with lithium and carbon (if there’s any left) as follows:

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These reactions have the potential to all occur at the same time. Tracking them properly would require calculus and lots of kinetics data including the activation energy of each reaction and the rate constant for each equation. Quick searches on the National Chemical Kinetics Database yields no results for most of these equations, which means we won’t be able to use a computer model to calculate exact quantities of each product. Instead, I’m going to run a computer simulation using Excel that makes the following three assumptions:

  • all these reactions occur at the same rate;
  • all these reactions are first-order with respect to the limiting reagent;
  • all these reactions are zeroth-order with respect to reagents in excess.

The results will be a close approximation of reality – they’ll be as close to reality as we can get with the data that’s available.

Here are the results of the simulation

Here’s a graph of the simulation running for 24 steps. Exactly one mole of carbon powder is added at step 5.

Periodic Table Smoothie - Let's Add Carbon Carbon quickly reacts to form lithium carbide, beryllium carbide and two organic molecules: methane and ethyne
Carbon quickly reacts to form lithium carbide, beryllium carbide and two organic molecules: methane and ethyne

Summary of results

The results are incredible! We’ve made ethyne and methane, both of which have the potential to do some really interesting chemistry later on. I’m hoping that we can make some more complex organic molecules after nitrogen and oxygen are added – maybe even aminoethane – let’s see.

Hydrogen has also re-formed. I’m hoping that this gas lingers for long enough to react with our next element, nitrogen: we might end up making ammonia, NH3(g).

You may have noticed that I removed the “boron-lithium system” from the vessel. The 0.178 moles we created are now stored separately and will not be allowed to react any further. With such little literature about the reactivity of B3Li, it’s impossible to predict what compounds it’ll form later on. B3Li is so rare that doesn’t even have a Wikipedia page.

Pressure in the vessel increases to 718 kPa after carbon is added
Pressure in the vessel increases to 718 kPa after carbon is added
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Mass of sludge in the vessel changes after adding carbon

Here’s what’s present in the vessel after adding carbon

Substance Moles present after 500 ‘steps’
He(g) 1.00000
Be(s) 0.51435
LiH(s) 0.27670
Li2C2(s) 0.27165
B2H6(g) 0.23300
Be2C(s) 0.17470
H2(g) 0.14267
BeC2(s) 0.13625
CH4(g) 0.00949

We also have 0.178 moles of B3Li stored separately in another vessel.

Next week, we’ll add nitrogen and see what happens.

Let’s add boron powder

elements110005
‘Boron’ page from Theodore Gray’s book, The Elements

Boron is a metalloid: an intermediate between the metals and non-metals. It exists in many polymorphs (different crystal lattice structures), some of which exhibit more metallic character than others. Metallic boron is non-toxic, extremely hard and has a very high melting point: only 11 elements have a higher melting point than boron.

British scientist Sir Humphrey Davy described boron thus:

“[Boron is] of the darkest shades of olive. It is opake[sic], very friable, and its powder does not scratch glass. If heated in the atmosphere, it takes fire at a temperature below the boiling point of olive oil, and burns with a red light and with scintillations like charcoal” – Sir Humphrey Davy in 1809

Initial condition

Before we add the 1.00 mol of boron into our reaction vessel, we need to recall what’s already in there from our experiments so far:

  • H2(g): 0.70 mol
  • He(g): 1.00 mol
  • Li(s): 0.40 mol
  • LiH(s): 0.60 mol
  • Be(s): 1.00 mol

The temperature of our vessel is 99 °C and the pressure of the gaseous phase is 525.5 kPa.

Now, let’s add our 1.00 mol of boron powder.

Which reactions take place?

Boron reacts with hydrogen gas to produce a colourless gas called borane, BH3(g), according to the following equation[1]:

image034.png

Boron also reacts with lithium in very complex ways. If we heat the vessel up to 350 °C, we’d expect to see the formation of a boron-lithium system with chemical formula B3Li according to this equation[2]:

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Notice that now we’ve heated up our vessel to 350 °C to allow this reaction to happen, the lithium at the bottom of the vessel has melted.

Boron reacts with lithium hydride as well, but only at temperatures around 688 °C. With our vessel’s temperature set at 350 °C, we won’t observe this particular reaction in our experiment.[3]

Some allotropes of boron – in particular, the alpha allotrope that was discovered in 1958 – is capable of reacting with beryllium to form BeB12. Because we’re using beryllium powder, which has semi-random  symmetry, we won’t see any BeB12 forming in our vessel. Alpha-boron only exists at pressures higher than around 3500 kPa. At our moderate pressure of only 525.5 kPa, powdered (semi-random) boron will prevail and no BeB12 will form.[4]

For simplicity’s sake, let’s assume that the two reactions above take place with equal preference.

Boron powder reacts with hydrogen gas

Let’s do an ice table to find out how much borane we make.

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A quick n/ratio calculation shows us that the hydrogen gas is limiting in this reaction:

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We can expect all of the hydrogen gas to react with the boron powder.

units are mol 2 B 3 H2 2 BH3
I 0.50 0.70 0
C -0.466 -0.70 +0.466
E 0.0333 0 0.466

Borane is very unstable as BH3, and it would probably dimerise into B2H6(g). This is still a gas at 350 °C and is much more stable than BH3. For the rest of this experiment we’ll assume that our 0.466 mol of BH3 has dimerised completely into 0.233 mol of B2H6.

Boron powder reacts with lithium

With the molar ratios present in our vessel, at 350 °C, we’d expect to witness the formation of a boron-lithium system, with chemical formula B3Li.

image030.png

A quick n/ratio calculation shows that in this reaction, the boron powder is limiting.

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All of the remaining boron therefore reacts with lithium. To calculate exactly how much B3Li we’ve created, let’s do another ice table:

units are mol 3 B Li B3Li
I 0.533 0.40 0
C -0.533 -0.178 +0.178
E 0 0.222 0.178

What’s in our vessel after adding boron?

We have the following gas mixture in our vessel:

Helium gas, He(g): 1.00 mol

Helium is an inert noble gas that will probably remain in the vessel until the end of the experiment. It’s used in party balloons.

Borane gas, B2H6(g): 0.233 mol

We made this today. Borane is used in the synthesis of organic chemicals via a process called hydroboration. An example of hydroboration is shown below.

250px-hydroboration-oxidation_of_1-methyl-cyclohex-1-ene

At the bottom of the vessel, there’s a sludge, which contains the following liquids and solids:

Molten lithium, Li(l): 0.22 mol

Lithium is used in the production of ceramics, batteries, grease, pharmaceuticals and many other applications. We’ve got 0.22 moles of lithium, which is about 1.5 grams.

Beryllium powder, Be(s): 1.00 mol

Beryllium is used as an alloying agent in producing beryllium copper, which is used in springs, electrical contacts, spot-welding electrodes, and non-sparking tools.

Lithium hydride, LiH(s): 0.60 mol

Lithium hydride is used in shielding nuclear reactors and also has the potential to store hydrogen gas in vehicles. Lithium hydride is highly reactive with water.

Boron-lithium system, B3Li(s): 0.178 mol

We made this today… but what is it? Not much is known about this compound – in fact, it doesn’t even have a name other than “boron-lithium system, B3Li”. It’ll probably decompose eventually in our experiment – maybe when we alter the pressure or temperature of the vessel at some later stage. We’ll need to keep an eye on this one.

The original H2(g) and B(s) have been reacted completely in our experiment.

What’s the pressure in our vessel now?

At the end of our reaction, the temperature of our vessel is still set at 350 °C and the pressure of the gaseous phase inside the vessel can be calculated to be a moderate 638 kPa as follows:

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*It should also be noted that some evidence exists for a reaction between LiH and BH3, forming Li(BH4). The reaction seems to take place stepwise with increasing temperature. A quick read of this paper suggests that in our vessel, which is at 350 °C, any Li(BH4) formed would actually break back down into boron powder and hydrogen gas, which would in turn react with each other and with lithium metal to form BH3 and LiH again. The net result would be a negligible net gain of LiH and a negligible net loss of boron powder. We will continue calculating this Periodic Table Smoothie under the assumption that if any Li(BH4) forms, it breaks down before we add the next element, and the overall effect on our system is negligible.

**Li(BH4) is an interesting compound: it’s been touted as a potential means of storing hydrogen gas in vehicles – it’s safer and releases hydrogen more readily than LiH, which was mentioned above.[5]

Next week, we’ll add element number 6, carbon, and see what happens.

References

  1. “Borane”. Wikipedia. N.p., 2016. Web. 14 Apr. 2016.
  2. Okamoto, H. “The B-Li (Boron-Lithium) System”. Bulletin of Alloy Phase Diagrams 10.3 (1989): 230-232.
  3. Matkovich, V. I. Boron And Refractory Borides. Berlin: Springer-Verlag, 1977. Print.
  4. Gaulé, G. K. Boron, Volume 2: Preparation, Properties And Applications. New York: Plenum Press, 1965. Print.
  5. Saldan, Ivan. “A Prospect For Libh4 As On-Board Hydrogen Storage”. Open Chemistry 9.5 (2011): n. pag. Web.

Let’s add lithium powder

Lithium: a page from Theodore Gray's book The Elements
Lithium: a page from Theodore Gray’s book The Elements

Initial condition

  • Hydrogen gas, H2(g): 1.00 mol
  • Helium gas, He(g): 1.00 mol

Last week, our vessel contained a mixture of hydrogen and helium gases. No chemical reactions have occurred so far, but that is about to change. Today, we’ll add 1.00 mole of lithium powder to the mixture and observe our first chemical reaction.

What does lithium look like?

Lithium is a soft, silvery metal with the consistency of Parmesan cheese. Lumps of lithium can be cut with a knife and it’s so light that it floats on oil. It would float on water as well if it weren’t for the violent reaction that would take place. Lithium is very well-known by science students for its ability to react with water, producing hydrogen gas and an alkaline solution of lithium hydroxide.

image022.png

There’s no water in our vessel so the above reaction won’t actually take place. We’ve only got hydrogen gas and helium gas inside. Let’s see if our powdered lithium reacts with either of those gases.

Will the lithium powder react in our vessel?

Yes! Lithium reacts with hydrogen gas very slowly. One paper by NASA cited a reaction occurring at 29°C but the yield and rate were both very low. Because I want to initiate as many reactions as possible in this experiment, I’m going to heat my vessel to 99°C by immersing it in a bath of hot water. According to the NASA paper, this temperature would give my reaction a 60% yield after two hours.

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Lithium hydride is beginning to collect in the bottom of my 10-litre vessel. It’s a grey-to-colourless solid with a high melting point.

How much of each substance do we now have in the vessel?

First, we need to know which reagent is limiting. We can calculate this by using the following rule:

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Let’s substitute the values into the expression for all the reactants in this reaction: Li(s) and H2(g).

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If the yield was 100% (i.e. a complete reaction), I’d expect to make 1.00 mole of lithium hydride. However, we’re only going to get 0.60 moles because according to the NASA paper, the yield of this reaction is only 60% at my chosen temperature.

Let’s do an ‘ice’ table to find out how much of each reactant reacts, and hence how much of each substance we have left in our reactor vessel.

units are mol 2Li H2 2LiH
I (initial) 1.00 1.00 0
C (change) -0.60 -0.30 +0.60
E (equilibrium) 0.40 0.70 0.60

By the end of our reaction, we’d have:

  • H2(g): 0.70 mol
  • He(g): 1.00 mol
  • Li(s): 0.40 mol (still solid: it melts at 180.5 degrees)
  • LiH(s): 0.60 mol

What does 0.60 mol LiH look like?

Let’s use the density formula to try find out how many spoonfuls of LiH we’ve created.

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We’ve made 6.11 millilitres of lithium hydride powder! That’s a heaped teaspoon of LiH.

What’s the resulting pressure in the vessel?

Our elevated temperature of 99°C will have caused a considerable pressure increase inside the vessel.

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That’s 5.2 atmospheres (atm) of pressure, which is quite high. A typical car tyre is about 2 atm for comparison.

What if the vessel exploded?

BANG. The contents of the vessel, after they’ve rained down on an unsuspecting crowd, would react explosively with the water and other compounds in our bodies to produce caustic lithium hydroxide and toxic lithium salts. I recommend stepping away from the vessel and behind a thick safety screen at this point. Even though our imaginary vessel is quite strong, we better put on a lab coat and safety glasses as well—just in case.

Conclusion after adding lithium powder

  • H2(g): 0.70 mol
  • He(g): 1.00 mol
  • Li(s): 0.40 mol (still solid: it melts at 180.5 degrees)
  • LiH(s): 0.60 mol
  • Pressure = 525.5 kPa
  • Temperature = 99°C

Next week, we’ll add 1.00 mole of beryllium to the vessel and see what happens.

Reference: Smith, R. L.; Miser, J. W. (1963). Compilation of the properties of lithium hydride. NASA

Let’s add helium gas

elements1100021
‘Helium’ page from Theodore Gray’s amazing book, The Elements

Last week, we put 1.00 mole of hydrogen gas into a cylinder. The resulting pressure was 243 kPa and the temperature was maintained steady at 20°C. This week, we’ll add 1.00 mol of helium gas, He(g), to the vessel and see what happens.

Will the helium react with the hydrogen?

No. Helium is completely inert. Hydrogen and helium will co-exist without undergoing any chemical reactions.

What will the resulting pressure be?

This is a very simple calculation. With 2.00 moles of gas in the vessel, the pressure would be double what it was before. This is known as Dalton’s law of partial pressures: the total pressure in a vessel is equal to the sum of all the pressure of the individual gases in the vessel.

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Let’s convert that into pounds per square inch (psi) for easy comparison with everyday objects.

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That’s about the same as a hard bicycle tyre.

How fast are the molecules moving?

Remember from last week that when our vessel contained only hydrogen gas, the molecules were moving around randomly with an average speed of 1760 metres per second.

Kinetic molecular theory states that the kinetic energy of a gas is directly proportional to the temperature of that gas. The formula for kinetic energy is shown below:

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At constant temperature, heavier particles move more slowly than lighter ones. Even though they have the same kinetic energy, helium atoms at 20 °C move slower than hydrogen molecules at 20 °C because they have almost exactly double the mass. How much slower does the helium move? Let’s find out.

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The molecules are moving at 1245 metres per second, or 4482 km/h. This is slower than the hydrogen gas by a factor of exactly root 2.

The molecules in our vessel could orbit the Earth in just 6 hours if they were to move in a single direction at this speed. Because the motion of particles in our gas mixture is random – they jiggle about rather than move in a single direction – they stay securely in the vessel.

Conclusion after adding helium

No chemistry’s happening in the vessel – not yet. Molecules of hydrogen and helium are simply co-existing in our vessel, bouncing off each other at different speeds and not interacting in any other way.

  • Hydrogen gas, H2(g): 1.00 mol
  • Helium gas, He(g): 1.00 mol

For some chemistry to happen, we’ll need to add the next element, lithium. We’ll do that next week.

Let’s add hydrogen gas

Hydrogen: a page from Theodore Gray's book, The Elements
Hydrogen: a page from Theodore Gray’s book, The Elements

I’m going to add 1.00 mol of hydrogen gas, H2(g), to our 10-litre vessel. We’ll assume that the entire experiment is carried out at normal room temperature – let’s say it’s 20°C.

How much does a mole of hydrogen cost?

Hydrogen gas is a relatively cheap element, and my one mole of H2(g) would cost less than one cent at wholesale prices. That said, the shipping, handling and service fee would be a couple of orders of magnitude greater than the cost of the gas itself, and I’d probably need to give the store about a dollar for the privilege of taking one cent’s worth of hydrogen gas.

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What does a mole of hydrogen look like?

We’ll assume the temperature is 20°C and the atmospheric pressure is 102.3 kPa, which is what the Weather app on my phone is reading right now. After the hydrogen gas has been released from its high-pressure storage cylinder, my one mole of H2(g) would have a volume of 23.8 litres at these conditions. That’s about enough hydrogen gas to fill up a party balloon.

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Hydrogen is a colourless, odourless gas that’s lighter than air. It’d float upwards very quickly if I opened the valve in the store. I’m now going to squeeze all that gas into my 10-litre vessel.

What’s the resulting pressure of the vessel?

If I squeeze that 23.8 litres of hydrogen gas into my 10-litre vessel, the resulting pressure in the vessel must be greater than atmospheric pressure (1 atm) because I’ve compressed the gas. We can calculate the final pressure precisely by using the ideal gas law: PV=nRT.

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That’s significantly higher pressure than atmospheric pressure, which varies from 100 kPa to 102 kPa under normal weather conditions.

Interestingly, the pressure in the vessel, 243 kPa, is equal to 35.2 pounds per square inch (psi), which is the same as the recommended pressure for a car tyre.

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Other than making random movements inside the vessel, the hydrogen molecules won’t really do anything else.

How fast are the molecules moving about?

We can calculate the average speed of the molecules by using the following equation:

*Note that R is the gas constant, 8.31, and M is the molar mass in kg/mol

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The molecules are travelling at about 1760 metres per second (on average).

How much distance will the gas molecules travel before they collide with one another?

For this question, we need to calculate something called mean free path. The mean free path is the average distance we can expect each molecule to travel before it collides with another molecule. Mean free path is quite long in a vacuum, and very short at high pressure conditions. One of the formulae used to calculate mean free path, λ, is shown below.

**Note that in this formula, pressure (P) must be measured in pascals (Pa)- not kilopascals (kPa). We therefore need to multiply our kilopascal pressure by 1000 to convert it from kPa to Pa.

*** Note also that d is the diameter of the molecules being studied in metres. Wikipedia tells us that hydrogen molecules have a diameter of 120 picometres. I’ve used this value in the equation below.

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The molecules in our vessel collide with each other roughly every 260 nanometres. That’s tiny: it’s just a few percent of the width of a cell nucleus!

How often do the molecules collide?

Let’s go right back to Year 10 Physics for this one. The time between collisions will be equal to the average distance travelled between collisions divided by the average speed of the molecules:

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The molecules collide with each other roughly every 0.1478 nanoseconds.

How many times do the molecules bump into each other each second?

By taking the reciprocal of the average collision time, we can find out how many times the molecules collide with each other every second, on average:

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Each molecule in our ten-litre vessel makes 6.765 billion collisions per second with neighbouring molecules.

Apart from lots of uneventful particle collisions – a total of 4.07 decillion uneventful collisions per second to be precise – not much else is happening in our ten-litre vessel at this stage.

Conclusion

  • Hydrogen gas, H2(g): 1.00 mol

Next week, we’ll add some helium to the vessel and see what happens.

Periodic Table Smoothie

periodic table by randall monroe what if.png
Image from Randall Monroe’s excellent book, What If?: Serious scientific answers to absurd hypothetical questions

Yesterday, I was wondering what would happen if we mixed the entire periodic table of elements together in a blender. Unsurprisingly, it would explode, scattering radioactive dust and debris for miles around in a red-hot fireball formed from the simultaneous fission of the entire seventh row. The periodic table would only need to be the size of a matchbox in order for this explosion to happen.

Calculating exactly what would happen would be incredibly difficult. There are so many simultaneous reactions – including nuclear reactions – taking place that it’s almost impossible to predict the outcome in any more detail than “KABOOM”.

Making a real Periodic Table Smoothie  would be prohibitively expensive. You’d need 118 particle accelerators (costing $1 billion each) all pointing at the same target just to get single atoms of each element to collide at the same time. This is even more difficult than it sounds: those elements near the bottom of the periodic table (numbers 105 and above) are so unstable that they’d break down before they even reach the target. There are massive financial and physical challenges to mixing an entire periodic table up in a blender.

Instead of adding all the elements at the same time, I’ll be adding one element each week to an imaginary 10-litre vessel and documenting – as a theoretical exercise – what happens. Ultimately, we all know it’s going to explode at some point. But when will it do that? How many elements are we able to add before it finally explodes? Will we create anything interesting along the way?

This very idea was floated on Reddit’s AskScience forum in 2013 but nobody actually figured out (seriously) what would happen.

Join me next week to start the experiment.

periodic table smoothie on reddit.jpg

 

What if we put 200 g ice into 1.00 L hot water?

Ice + water --> ice water
How much of a chill will these ice cubes give to a bucket of hot water?
Today, we’re going to answer the following question:

When 200 grams of ice is added to a bucket containing 1.00 litre of hot water, what’s the final temperature of the water?

To answer the question, we’re going to need to make some assumptions. We’ll take 1.000 litre of pure water at 80.00°C and add 200.0 g of ice (at -10.00°C) to it. What’s the final temperature of the water?

Part 1: Heat transfer method

The following equation can calculate the temperature at thermal equilibrium of any number of objects in thermal contact.

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I love this equation because it’s several lines of maths shorter than the version taught in school. With this equation, you don’t even need to convert the temperatures into kelvin. Celsius works just fine.

Let’s set up the equation so that the addition series contains the variables in the question.

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Now, let’s substitute the gives values into the equation. The specific heat capacity of water is 4200 J kg-1 K-1, and that of ice is 2100 J kg-1 K-1.

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Great! Adding 200.0 g of ice to 1.000 L of water decreases the temperature from 80.00°C to 71.80°C.

But we’ve forgotten something. The ice will melt as soon as it hits the hot water. Since melting is an endothermic process, heat energy from the water will actually be absorbed, thus reducing the final temperature even further.

Part 2: Let’s take into account the fact that the ice melts!

Remember our formula from part 1.

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The amount of energy required to melt ice can be calculated using the latent heat equation:

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Removing that amount of heat energy from the system results in the following equation:

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Great! Now, we’ve calculated that the final temperature of the water would be 57.36°C after the addition of the ice. That’s equal to 330.5 kelvin, which will be useful later.

However, we’ve forgotten to take something else into account: how much heat will be lost as radiation from the surface of the bucket?

Part 3: What’s the rate of heat loss from the bucket by radiation?

The rate of heat lost by radiation can be calculated by using the Stefan-Boltzmann equation, below.

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P is the rate at which heat energy is radiated from the surface of the bucket in watts. Emissivity, e, of water is 0.95, and the surface area, A, should be around 0.0707 m2 for a one-litre bucket. Calculation of A is shown below. Assuming that the radius of the surface of the bucket is 6cm:

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Plugging that value into the equation, we can find P. We’ll assume that the experiment is being conducted at room temperature and the temperature of the surroundings is 20.00°C (29.03 K).

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This means that 2.928 joules of energy are emitted from the surface of the bucket every second. Ten minutes later, the bucket would have lost 1756.8 joules of energy due to radiation from the surface. But what about emission of radiation from the sides of the bucket?

Let’s say that our bucket is made from highly polished aluminium (which has emissivity 0.035) and it holds exactly 1.2 litres of water. We need to calculate the dimensions of the bucket.

Assuming it has straight sides (i.e. it’s a cylinder), the bucket had volume equal to the following formula:

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The surface area of our bucket (excluding the open surface at the top) is:

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The rate of energy radiation from the sides would therefore be:

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It’s interesting to note how very little radiation is emitted from the shiny aluminium bucket, while lots more radiation is emitted from the surface of the water. This is because relatively ‘dark’ water has a much higher emissivity than shiny aluminium. Total emission from the bucket is therefore:

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After ten minutes, the bucket would have lost the following amount of energy:

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Let’s factor this amount of energy loss into our final temperature equation.

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Not much energy is lost via radiation! Finally, let’s find the peak wavelength of the radiation emitted by the object using Wien’s law.

Part 4: What’s the wavelength of the radiation being emitted by the bucket?

Here’s Wien’s law from Unit 1 Physics…

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The radiation emitted from the resulting bucket of water lies firmly in the infra-red part of the electromagnetic spectrum. The bucket would be clearly visible on an infra-red camera!

Next week, we’ll begin a new a Chemistry-themed project called Periodic Table Smoothie. More next week.

Combining Chemicals And Students Safely

Chemistry lab. Image supplied by National Laboratory Sales
Image supplied by National Laboratory Sales

In science education, chemistry is one of the disciplines that involves regular hands-on work in a laboratory. While teaching students the intricacies of chemistry presents no exceptional risk, the very real dangers posed by many chemicals demand a higher level of safety consciousness and preparedness. This general overview outlines sensible security precautions for high school and college chemistry labs.

The Importance Of Documentation

Fortunately, in a classroom setting, all of the chemicals being used will be well understood. This means information on their potential risks is widely available. This information must be used to ensure that each substance used is treated with the proper respect for the dangers it poses.

The first source of information for any chemical is the label it carries. These always describe their hazards, but labeling may be incomplete. A more authoritative source for hazard information is the material safety data sheet (usually referred to as an MSDS) for the substance. A comprehensive reference collection of MSDSs is an integral part of every laboratory, and this collection needs to be freely available to all teachers using the classroom’s chemical supply.

Equipment And Facilities

At the high school or college level, chemistry experiments demand their own dedicated laboratory spaces. These labs should meet all state and national safety requirements and cannot be used for teaching other subjects. Even the scheduling of laboratory use must be geared towards safety. Adequate free periods must be included every day for cleaning the lab and disposing of chemicals.

Chemicals need a dedicated, lockable storage room equipped to contain them safely. A prep room is also required for teachers to use. This needs equipment similar to the lab room albeit on a smaller scale. For all three of these spaces, ventilation is a critical concern. Ventilation hoods should be used in the lab itself and all of the air removed from the lab must be vented outside.

Full safety equipment needs to be available for everyone in the laboratory while chemicals are in use. This includes both permanent safety facilities (e.g. eyewash stations, first aid kits, etc.) and personal protective equipment (PPE), including goggles. Goggles for use in chemistry labs must conform to stricter standards than other forms of eye protection to ensure that they protect against both flying debris and liquid splashes.

Planning And Preparing

Every chemistry lab needs thorough safety plans for both general and specific chemical risks. While standardized materials including the safety documentation discussed above can be used to prepare safety plans, each teacher responsible for leading classes in the lab has a responsibility to set out his or her own safety measures.

Customized safety preparations should take the specifics of the facility and the coursework into consideration. Methods for calling for help, evacuating the lab, and documenting incidents will vary based on the layout of the facility and its resources. By designing their own safety plans, teachers will be better prepared to enact them in the event of an accident.

The Teacher’s Role

A chemistry teacher has many responsibilities beyond instruction and safety planning. One of the most important of these responsibilities is teaching his or her students to share a healthy respect for the hazards posed by chemicals. Teaching and testing them on basic safety precautions and lab-specific emergency procedures is just a start.

Students should learn to understand the intricacies of chemical labeling before working with hazardous chemicals. (For example, the terms danger, warning, and caution are each distinct, indicating decreasing levels of risk.) At the college level, where students may be working independently and designing their own experiments, teaching them to read the MSDS is strongly recommended. For younger students teachers can often make use of intermediate-level warning documentation (e.g. CLIPs, Chemistry Laboratory Information Profiles) to give them adequate chemical reference materials.

Keeping students safe in the laboratory is not a difficult job. It requires a heightened sense of awareness and an amount of preparation commensurate with the hazards posed by the chemicals involved. When preparedness is combined with proper facilities, equipment, and training, schools labs can be safe places to learn through direct experimentation with all but the most dangerous of chemicals.

Whether you’re building a new Lab or upgrading your existing one, you will find a remarkable selection of Casework, Workstations, Fume Hoods and related lab products at National Laboratory Sales.

(Almost) Nothing is Truly ‘Natural’ – Part 4

Cezanne nothing is natural fruit and vegetables painting still life
Nothing on this table is natural – not even the fruits. The Basket of Apples by Cézanne

Corn isn’t ‘natural’

In 2014, I created a series of infographics to help convey this message. Corn, for example, used to be a spindly grass-like plant called teosinte, which Native Americans farmed and bred through artificial selection until it resembled the yellow corn of today.

In 9000 years, sweetcorn has become 1000 times larger, 3.5 times sweeter, much easier to peel and much easier to grow than its wild ancestor. In the 15th century, when European settlers placed new selection pressures on the crop to suit their exotic taste buds, the corn evolved even further to become larger and multi-coloured. Corn no longer resembles the original teosinte plant at all.

Watermelon isn’t ‘natural’

Watermelon began as a hard, bitter fruit the size of a walnut. It caused inflammation and had an unpalatable bitter taste. Thousands of years of artificial selection (unintentional genetic engineering) have resulted in a modern watermelon that bears no resemblance to its African ancestor. Modern (artificial) watermelons are sweeter, juicier, more colourful and easier to grow than their ancestral varieties.

Peaches aren’t natural, either

Peaches used to be hard, cherry-sized fruits with giant pips. Like corn and watermelon, peaches became larger, sweeter and juicier over thousands of years of inadvertent genetic engineering.

Bananas, wheat, pigs and all farmed animals and plants are not natural

Before agriculture, carrots were white and spindly. Wheat was tall and scrawny with little calorific value. Apples were tiny and sour with giant pips (like crab-apples today). Strawberries were tiny, bananas had stones in them, and pigs were viscous creatures with tiny backsides that made for a not-so-delicious ham. Cows didn’t produce much milk (just enough for their own calves) and chickens were skinny little creatures that laid eggs weekly rather than daily. Every species that’s ever been farmed by humans has been genetically modified over time as a result.

I keep making this point because our ancestors deserve credit for their hard work: they toiled in the fields for thousands of years to breed plants and animals that are suited to our modern tastes and lifestyles. For modern humans to call the results of our ancestors’ hard work ‘natural’ is an insult to the millions of ancient farmers who worked so hard to produce them.

Engineers (including genetic engineers) know that humans have toiled for millennia to change nature and suit it to our own needs – animals became tamer and meatier, and plants started producing more edible portions. I want to counteract the misconception that humans encountered nature in a ‘pristine’ state.

Great documentary snippet – Animal Pharm

[ancient humans] toiled in the fields for thousands of years to breed plants and animals that are suited to our modern tastes and lifestyles. For modern humans to call the results of their hard work ‘natural’ is an insult to our ancestors.

I show the above documentary my Year 10 Science students to demonstrate what is currently being produced using genetic engineering techniques. The video explains all the concepts mentioned in this article and is accessible for and educated audience of any age.

This post is part 4 in a weekly series on chemophobia. Next week, we’ll look at the psychology behind chemophobia.

On the $$$ fuelling Chemophobia – Part 3

We’ve already asserted that chemophobia is an irrational psychological quirk that gained traction after the environmental movement of the mid-1960s. But I don’t want to make such allegations without proof. In part 3 of this weekly series on chemophobia, I’ll show you some of the irrational conclusions that chemophobia leads us to make, and the psychology that lies behind them. We’ll also look at some examples of companies that are using chemophobia with maximum leverage to inflate the prices of foods and skincare products in stores.

People perceive products with moral claims on the packaging as more effective than those without

Boyka Bratanova at Abertay University offered participants a choice between two cookies: one was normal, and another was labelled “organic/locally-produced/carbon-neutral”. The cookies were otherwise identical.

people believe these organic cookies taste better

Amazingly, when the participants were asked specifically to evaluate the taste of each cookie, they consistently rated the ‘morally-superior’ cookies as more delicious. Bratanova’s study confirms Meng Li’s hypothesis (discussed last week) that people confuse moral claims with actual superiority. Manufacturers are taking advantage of this psychological trick by writing meaningless claims of moral superiority such as “natural”, “pure” and “free from {insert harmless ingredient here}” on their product labels to justify price increases at the point of sale.

The global market for ‘natural’ and ‘organic’ personal care products is projected to reach US$16 billion by 2020. But are these ‘natural/organic’ products really any better than their non-organic equivalents? Evidence suggests not.

Take Gaia Natural Baby Skin Soothing Lotion, for example, which sells for 4.4 cents/mL in Coles. A comparable ‘normal’ product, Johnson’s Baby Lotion, sells for just 1.7 cents/mL. Gaia can charge its customers 2.5 times the price compared with traditional Johnson’s Baby Lotion largely because it claims “Pure, Natural, Organic” in large text on the front of the bottle. Unfortunately, these claims aren’t actually true (and this product was recalled in December 2015 because of its ‘inaccurate product label’; read more here).

Gaia makes these three misleading claims on all of its products
Gaia makes these three misleading claims on all of its products

“Pure” is a claim reserved for single-ingredient products only

By definition, mixtures such as baby lotion cannot be ‘pure’. Pure substances contain only a single ingredient (e.g. pure salt, pure white flour, pure cane sugar and pure spring water). No cosmetic or skincare product should ever be labelled ‘pure’.

“Natural” products must be sold as they’re found in nature

Very few products are truly natural. Not only is the definition vague, but there are no enforceable regulations on its use in Australia, New Zealand or the US. The Food Standards Agency in the United Kingdom proposes some guidelines: “made from natural ingredients that have not been interfered with by [humans]”. Again, it’s impossible for any cosmetic or skincare product to be totally natural. All cosmetics and skincare products have been ‘interfered with’ by humans, and they the vast majority of skincare products contain artificial ingredients.

“Organic” only makes sense when applied to foods

Adding a couple of drops of ‘organic’ ingredients into your product to justify writing “organic” on the label should be illegal. But that’s exactly what Gaia has done: the ingredients certified ‘organic’ in their Natural Baby Skin Soothing Lotion amount to approximately just 7% of the product.

Because ‘organic’ is a farming technique, farmed foods are the only products that should ever be labelled ‘organic’. It’s impossible for cosmetics and skincare products to be ‘organic’ because many of the ingredients (even in self-proclaimed ‘natural’ brands such as Gaia) are artificially synthesised rather than grown.

Consumers are being tricked into paying a higher price for a product that isn’t necessarily superior.

Natural chemicals can be harmful, too (and the most harmful compounds on Earth are all natural)

Gaia’s “all-natural” baby lotion was recalled because it contained undisclosed allergens. Nine out of the top ten most dangerous compounds on Earth are naturally-occurring. When it comes to skincare, synthetic compounds are often gentler and more suited to their purpose than are their natural counterparts.

Natural compounds are sometimes far more dangerous than synthetic ones. Blue, artificial compounds; green, naturally-occurring compounds.
Natural compounds are sometimes far more dangerous than synthetic ones. Blue, artificial compounds; green, naturally-occurring compounds.

Some studies even suggest that crops on organic farms produce more pesticide within the leaves in order to protect themselves from increased rates of insect predation. Some of these natural pesticides are actually more potent skin irritants than the synthetic pesticides used in conventional farming methods.

In addition, organic crops can be sprayed legally with many pesticides, some of which are potent irritants. Lists of pesticides approved for use on organic farms can be found here and here. There exists a misconception among consumers that organic produce is ‘pesticide-free’, which is a concern considering that ‘no pesticides’ is the most common argument heard in favour of buying organic produce.

Consumers are being tricked into paying a higher price for a product that isn’t necessarily superior, and still might contain harsh (natural) compounds that irritate their skin.

Many brands are making these misleading claims…

Some of Sukin's "fragrance-free" products contain fragrances such as sesame oil and rose hip oil
Some of Sukin’s “fragrance-free” products contain fragrances such as sesame oil and rose hip oil
Envirocare's hair cleanser made extreme 'natural' claims before it was recalled by the Australian Government. Source: recalls.gov.au
Envirocare’s hair cleanser made extreme ‘natural’ claims before it was recalled by the Australian Government. Source: recalls.gov.au
Mustela's milky bath oil claims to be 'natural' but contains mostly artificial ingredients
Mustela’s milky bath oil makes a vague claim about having ‘natural ingredient [sic]’ but contains mostly artificial ingredients e.g. PEG-6 isostearate and propylene glycol
Sukin makes claims that aren't even relevant to the product being sold. Moisturisers are labelled "SLS-free", for instance. SLS should never be in a moisturiser!
Sukin makes claims that aren’t even relevant to the product being sold. Moisturisers are labelled “SLS-free”, for instance.
Sometimes, the ingredients labels make no sense whatsoever. They've put a 'word salad' instead of actual ingredients on this one. This product should be recalled or over-labelled immediately.
Sometimes, the ingredients labels make no sense whatsoever. They’ve put a ‘word salad’ instead of actual ingredients on this one. This product should be recalled or over-labelled immediately.

Update: Gaia has recalled the product above due to its ‘inaccurate product label’

Their signature baby lotion is being withdrawn from sale due to an undisclosed ingredient labelling problem… Gaia was unable to provide any further information and declined to comment on the issue.

Gaia has recalled the product mentioned in this article due to the presence of undisclosed allergens
Gaia has recalled the product mentioned in this article due to the presence of undisclosed allergens. Source: recalls.gov.au

On the Pervasiveness of Chemophobia – Part 2

Bill Gates drinks water purified from sewage at Seattle's Omniprocessor plant
Bill Gates drinks water purified from sewage at Seattle’s Omniprocessor plant

Would you drink water that’s been purified from sewage? Bill Gates did:

“It’s water,” he says. “Having studied the engineering behind it… I would happily drink it every day. It’s that safe.” – Bill Gates

He’s talking about the Omniprocessor in Seattle, USA, which illustrates perfectly the prevalence of chemophobia in our society. The Omniprocessor takes sewage waste and purifies it into clean drinking water. The dried sewage is then combusted to power the plant, producing electricity that can be sold back to the grid. Essentially, it’s a free sewage disposal system that also gives you clean drinking water and a plentiful supply of electricity. Omniprocessors could be a huge income boost for farmers in developing countries.

The plant in Seattle was met with resistance. One study showed that 26% of survey participants were so disgusted by the idea of “toilet-to-tap” that they agreed with the statement: “sewage water could never be purified to such an extent that I would be willing to drink it”. Try it yourself: which glass of water would you rather drink?

We all feel a slight preference for the glass on the right. Chemophobia, an irrational psychological quirk, is more prevalent than you might think.
We all feel a slight preference for the glass on the right. Chemophobia, an irrational psychological quirk, is more prevalent than you might think.

If science tells us the purified sewage-water is perfectly clean, then why aren’t people comfortable with drinking it?

Instinct: Once contaminated, always contaminated

Paul Rozin at the University of Pennsylvania provides an explanation. He uses the term “contagion” to describe the perceived, permanent grossness that objects or substances acquire once they have touched something disgusting. No amount of purification can remove the ‘disgust factor’ that’s been acquired by the object. It’s purely psychological, and has no basis in science, but might have evolved as a useful behavioural adaptation that protects us from disease.

Mark Schaller at the University of British Colombia coined the phrase “behavioural immune system” to describe this phenomenon. It includes a suite of feelings and behaviours, including repulsion and disgust, that prevent us from eating contaminated food. It’s overly sensitive, and is at the root of many culinary taboos (e.g. don’t eat pork/prawn/insects).

All of this makes evolutionary sense: for millions of years of human evolution, we had no way of purifying food once it had become contaminated. We had no way of boiling water (and no fire) for 90% of human history. We had no modern medicines for 99% of human history, which made even small illnesses a horrifying, life-threatening prospect. Paranoia about cross-contamination has probably saved our species from extinction.

So why do some people see ‘synthetic chemicals’ as contaminants?

Science teachers are partly to blame. I tell my students never to eat in the lab because we’re fearful of contaminating the student’s food with lab chemicals, which might make them ill. I tell my students never to pour back into the stock solution because we might contaminate the stock solution, ruining future experiments. When an unidentified clear liquid (either pure water or a highly corrosive acid) splashes onto a student’s skin, I tell them to assume it’s the highly corrosive acid and wash immediately with copious amounts of water, just in case. Science teachers inadvertently instil in students a fear that laboratories are highly contaminating places. We do this with the absolute best of intentions.

Science teachers contribute to the notion that labs are full of contaminants.

Paranoia about contamination in laboratories has likely prevented countless accidents worldwide. It’s saved lives and limbs, too, and that’s why teachers must keep emphasising these safety messages. In doing so, however, do need to be mindful of the the unfortunate side-effect of ‘contagion’, which is the gut instinct that foods and lotions (or even water) created in a lab must be contaminated with something nasty. We need to counteract that notion in the following way.

We must emphasise purification techniques in school

When my students made aspirin last week (about 8 tablets’ worth), I told the students we cannot ingest the aspirin because “it’s contaminated: it contains unknown impurities”. Similarly, when we made esters last term (edible artificial flavourings), I told the students not to touch the esters or smell them too closely because they “contain contaminants such as highly corrosive sulfuric acid”. These safety warnings are valid and necessary – they’re actually a legal requirement of my job.

In industry, however, both aspirin and esters (and everything else) would be purified after production to a very high standard (usually 99.99%) before being certified safe for human consumption. Generally, however, high-school chemistry students don’t learn about purification techniques – not even in theory – so for them, the laboratory remains a dangerous place where dirty, contaminated things are created. Inadvertently, that’s become the take-home message from high-school science.

“…for [students], the laboratory remains a dangerous place where dirty, contaminated things are created.”

Purification techniques such as fractional distillation, centrifugation, recrystallisation, affinity purification and liquid-liquid extraction are all beyond the scope of a high-school chemistry course. Water purification and extraction of substances using supercritical carbon dioxide (scCO2) are in the Year 11 textbook, but these topics are not taught by many schools. Students don’t need to know the details – but they do need industrial relevance built into their course, and they need to be made aware that many of the products we use were made or designed in labs. Most importantly, they need to know that these products were purified to a high standard before being put to use.

People go for ‘natural’ products because they try to avoid potential contaminants from the laboratory

After years of hearing these messages in school, it’s no surprise that some people are so averse to eating foods or using products made in a lab. As one of my survey respondents put it so succinctly:

“If I can’t eat in a lab due to fear of contamination, how could food made in lab possibly be safe to eat? If I have been taught to treat every lab chemical that gets onto my skin as potentially corrosive, how could a moisturiser made in a lab from synthetic ingredients ever be good for my skin? This goes against what I’ve been taught throughout school!”

Science education in schools might just be one of the root causes – and one of the solutions – to the widespread prevalence of chemophobia. More next week.

This post is part of a weekly series on chemophobia. Read part 1 here.