What Do You Call A Left-Handed Lemon? QI

QI is a high-intelligence television show in Britain, formerly hosted by Stephen Fry and now hosted by Sandi Toksvig.

In this clip, the QI panelists are asked, 'what do you call a left-handed lemon' and subsequently learn that the molecule that produces the distinct smell of a lemon is a chiral molecule meaning that it has a mirror image that cannot be superimposed upon the original molecule and that the mirror image molecule produces the smell of an orange instead. 

Source - wikipedia

Chirality is real and present in any molecule where a central carbon atom has four unique substituent groups off of the same center. Think of the molecules as being similar like your left and right hands. They look identical but can't be rotated in any way to make them overlap identically. Instead, they would have to be 'mirrored' to allow for the overlap.

Interestingly, I read an awful Fantastic Four comic a few years back based on this idea of chirality, but I digress.

Sadly, even though limonene is, indeed, chiral with mirror images of the compound existing, those mirror images aren't really the reason for the difference in the smells of lemons and oranges. According to the American Chemical Society, that's a myth.

Actually, both oranges and lemons contain mostly (R)-limonene. Only 1-4% of the limonene in either fruit is in the (S) configuration. As for what these enantiomers actually smell like, (R)-limonene does have a pleasant, citrusy aroma, but does not smell like oranges. Instead, various other, fragrant molecules found in orange oil carry the odor. At high purity, (S)-limonene carries notes of turpentine and lemon. However, this enantiomer is barely present in lemons and is unlikely to contribute much to their aroma. As with orange odor, a number of different molecules in lemon oil contribute to lemons’ fresh scent.

Bath Bombs - Periodic Table of Videos

Bath bombs are just glorified, perfumed alka seltzer tablets. They're primarily made of sodium bicarbonate (baking soda) and citric acid that result in this reaction...

3 NaHCO₃ (s) + H₃C₆H₅O_{7 (s)} --> Na₃C₆H₅O_{7 (aq)} + 3 H₂O _(l) + 3 CO_{2 (g)}

The cuteness of the dissolving, reacting Mad Scientist bath bomb is fun to watch, but there isn't too much really exciting in this video other than some chemistry folks playing around with the bath bombs - adding them to water, using a thermal camera to check the endothermicity of the reaction, checking the dyes under UV light, adding concentrated sulfuric acid to the bomb (oof), and finally trying to set the poor bath bomb on fire.

Feels a bit like the Nottingham folks are reaching a bit for content here.

How do I tell my teacher the fluorine cation doesn't exist?

From reddit

See, it's funny because the teacher gave the student an F+ on his or her (possibly AI-generated) book report, but the student is claiming not to know that the F+ is meant to be a grade and not a chemical notation for a fluorine atom that has lost an electron. 

Fluorine atoms, being the most electronegative atoms on the planet, are incredibly unlikely to lose an electron rather than to gain an electron.

See, it's funny because of periodic trends!
 

What happens if you eat a silica get packet? - Vivian Jiang

Do not eat.

It's such a simple instruction that we've all read a hundred times or more on the tiny silica gel packets that come in sneaker boxes, shirts shipped from warehouses, and many more fabric and leather goods.

But why shouldn't you eat silica gel? If it's just silica, then it's the same as sand. While eating sand might be unpleasant, it's not necessarily unsafe if it's clean sand.

The increased surface area of the silica gel - one gram of silica gel has more than 700 square meters of surface area according to the video - is the issue. That surface area and its attractiveness toward polar molecules - water, ammonia, and other small molecules - cause it to absorb 40% its weight in water, making it a spectacular desiccant. 

In general, the silica gel wouldn't do too much harmful to your body unless it had a cobalt chloride coating.

Analytical chemist water

Source: reddit

Water is water is water, right?

No, as I've posted here before, not all water is equal. 

The above video distinguished among four water types found in this particular analytical chemist's lab.

First is tap water. That's the stuff that is piped into our homes and businesses from the local municipality. Generally, in the United States, it's pretty clean and safe to drink. Depending on where you are, however, it could have various dissolved ions in it because of the pipes and rocks that the water passed through on its way to the water treatment facility and onward to your house.

Second is deionized (DI) water. To produce DI water, tap water is run across resin beads what allow for ion exchange. The positive ions in the tap water are absorbed by the beads and replaced in the water with hydrogen ions (H+) and the negative ions are replaced with hydroxide ions (OH-). Eventually those beads have to be recharged as their capacity to absorb ions is finite. 

DI water is not the same as distilled water, though both are 'cleaner' than tap water alone. I have used both distilled and DI water in college and summer camp chemistry labs. Both are certainly good enough for the chemistry work that we do on a high school level.

Third is MillQ water, produced by a three-stage process which is already light years beyond anything I've ever used in a lab. The video voice describes it as 18.2 megaohm[·cm] which measures the water's resistance to current. The more dissolved ions (electrolytes) water has, the lower its resistance.

Fourth, she mentions LCMS-grade water means Liquid Chromatograph/Mass Spectrometry water. I'm already out of my depths to explain why this water is purer than the previous water much less the final water she mentions - Optima LC/MS water.

However, as the comments on the video mention, all of this is problematic because of how the various waters are stored - dissolved silicium from glass bottles or CO2 or plasticizers if stored in polymer bottles.

How the World's Most Expensive Color is Made

This video definitely doesn't make me sad, though I would understand why you might end up a bit blue after learning about the manufacturing process of lapis lazuli-based paints.

The Cennini method described here is understandably expensive - because it's insanely labor-intensive.

Understandably, Mohammed has a less labor-intensive method that he developed, but he's not sharing that with us in the video.

From about 6:40 onward, the video shifts from following the production method to looking into the mining of lapis lazuli in Afghanistan, a more political discussion than the initial portion of the video. Then they come back to Mohammed as he explains why natural, lapis-based paints are 'better' than its synthetic replacements.

Units meme...

 Yeah, that's about right...I've said almost that exact phrase to my students probably a million times.