77
votes
Accepted
Why don't we explode after drinking water?
The hydrochloric acid in the stomach is already quite dilute; its pH is in fact no less than 1.5 so that at the extreme maximum there is only 0.03 molar hydrochloric acid. And even that small amount ...
- 61.1k
75
votes
Why would breathing pure oxygen be a bad idea?
The other answers here, describing oxygen toxicity are telling what can go wrong if you have too much oxygen, but they are not describing two important concepts that should appear with their ...
- 909
69
votes
Accepted
Why doesn't frozen sugar solution taste sweet?
Where is the sugar?
When you freeze a dilute aqueous sugar solution pure water freezes first, leaving a more concentrated solution until you reach a high concentration of sugar called the eutectic ...
- 61.1k
61
votes
Accepted
Can we fill potato chips bags with a gas other than nitrogen?
As Nilay Ghosh said, nitrogen is cheap. Very cheap. Neon is expensive. Argon is cheaper than neon, but considerably more expensive than nitrogen. Helium is also expensive and needs to be used wisely, ...
- 5,070
52
votes
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Why does burnt hair smell bad?
Hair is largely (~90%) composed of a protein called keratin, which originates in the hair follicle.
Now, keratin is composed of a variety of amino acids, including the sulfur containing amino acid, ...
- 18.8k
52
votes
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What causes the "rotting fish smell"?
The "fishy" odor that you're familiar with is brought about by a whole bunch of compounds, and not any single one. Then again, if we were to narrow this down a bit, we could say that simple nitrogen ...
- 18.8k
51
votes
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How to properly store acids at home?
First I'd locate the bottle which causes the problem. Usually HCl is #1 suspect, but to be sure you can put a vial with smelling salts (aqueous solution of $\ce{(NH4)2CO3}$) or ammonia in the box with ...
- 38.4k
48
votes
Can we fill potato chips bags with a gas other than nitrogen?
Not mentioned yet: nitrogen is entirely non-toxic, environmentally friendly, does not contribute to global warming or ozone depletion.
In very good approximation, nitrogen is just air with the oxygen ...
- 869
45
votes
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Why does whipped cream use nitrous oxide instead of nitrogen gas?
There are two ways to efficiently make an aerosol product:
Use a gas that liquifies under the pressure inside the can. For example, butane lighters. Nitrogen is one of the "fixed gases", meaning it's ...
- 1,211
45
votes
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How are poisons discovered? Does someone have to die/be poisoned from it first?
Alle Dinge sind Gift, und nichts ist ohne Gift, allein die Dosis macht dass ein Ding kein Gift ist (The dose makes the poison) - Paracelsus
Poisons (I'm going to use this as an umbrella term for "...
- 18.8k
40
votes
Does the mass of sulfur really decrease when dissolved in water and increase when burnt?
Upon reading the answers on Quora (thanks S007 for pointing that out) I realized this trick question is a lousy play upon two somewhat peculiar features of sulfur:
When submerged in water (not "...
- 31.4k
40
votes
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What properties of carbon dioxide make it a greenhouse gas?
According to the Intergovernmental Panel on Climate Change (IPCC):
"Greenhouse gases are those that absorb and emit infrared radiation in the wavelength range emitted by Earth."
In order for a ...
- 17.6k
35
votes
Accepted
Why does chocolate melt so easily?
tl;dr The main structural component of chocolate is cocoa butter, which is a blend of fatty acids (primarily oleic, palmitic, and stearic acids). Cocoa butter has multiple crystal structures, and ...
- 3,393
35
votes
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Why does adding salt to boiling water cause it to flare up suddenly?
The salt does not instantly dissolve so the surface of the crystals suddenly provides a lot of nucleation sites for the water to form vapour - hence the surge as it boils from these surfaces. The ...
- 22.7k
34
votes
Accepted
A glass of water with ice-cubes in it. Where's the water the coldest; at the top or bottom?
Interesting question!
A few things first:
As the ice melts, it cools the water around it.
Technically, the ice cube melts because the water cools down. This may sound ridiculous at first, but you ...
- 18.8k
33
votes
Accepted
Sugar solutions have a neutral pH in themselves, but it makes your body acidic. Why?
It is not proven that "sugar makes your body acidic"!
Your body's pH is very tightly regulated by the body's internal systems; it is also different in different parts of the body - the stomach is ...
- 22.7k
31
votes
Why would breathing pure oxygen be a bad idea?
Our body is used to the environment around us. Once you change part of the environment, you have to be ready for the consequences.
Inhaling pure oxygen is the cause for what is known as oxygen ...
- 10.7k
31
votes
Why do shampoo ingredient labels feature the term "Aqua"?
There are three reasons which I can see:
labelling regulation and a common nomenclature of ingredients,
ubiquity of the term aqua,
the romantic ring to the word.
I shall expand upon the first as the ...
- 7,169
30
votes
Why does whipped cream use nitrous oxide instead of nitrogen gas?
According to Nitrous oxide, carbon dioxide, and their mixtures as propellants, Proc. Chem. Specialties Mtrs. Assoc., June 1950, page 45, William Strobach, $\ce{CO2}$ and $\ce{N2O}$ are both suitable ...
- 40.9k
29
votes
Microwaving a glass of water, what happens?
Heating water on a hot plate is safe, because the hottest point is at the bottom of the pot. A lot of relatively small bubbles appear there without much overheating of the water, because there is a ...
- 12.2k
29
votes
Accepted
Can drinking a lot of water be fatal?
Based on what I gathered from this Wikipedia article, Yes.
Drinking copious amounts of water can prove fatal. The proper term is "Water intoxication".
When you start taking in a lot of water (by "a ...
- 18.8k
29
votes
Can we fill potato chips bags with a gas other than nitrogen?
Substances that are gaseous down to, say, -10 are finite (and not very large) number.
Of these, we want:
Safe against ignition (so no hydrogen or gaseous hydrocarbons)
Not poisonous (phosphine, arsine,...
- 825
29
votes
The importance of the cold chain in the food and the pharmaceutical industry
Avoiding cooling again after keeping it (for noncritical products) at room temperature is mainly to prevent forgetting it was not cold all the time and that it may not last as long as expected.
Taking ...
- 43.3k
28
votes
Accepted
How 'heavy' should an element be, to be a "Heavy Metal"?
There is no true, accepted definition of heavy metal. I was taught to apply the option a metal that has density equal to or over $5.0\ \mathrm{g/cm^3}$.
Other variants include a different density ...
- 7,169
28
votes
Accepted
Why is heroin a more potent drug than morphine, despite having a similar structure?
The answer to this question lies in the pharmacokinetics of these two drugs: the acetyl groups cause Heroin to be 200 times more lipid soluble than Morphine1. Another example of a common drug would be ...
- 6,278
27
votes
Realistic chemical spill accident in high school chemistry class
Collecting together the responses from the comments and Ben Norris's answer and adding one of my own, individual solutions in water of the following chemicals are realistic options for a liquid spill ...
- 17.4k
27
votes
Is there such a thing as a "minimal soap" molecule?
It boils down to the definition of soap. Wikipedia defines a soap as the salt of a fatty acid.
IUPAC claims the smallest fatty acid can be considered to have 4 carbons.
Therefore the simplest soap ...
- 1,422
27
votes
Accepted
Are food calorie values really integers?
They're not exact numbers. These numbers aren't exact for three reasons:
Each type of carb, protein, and fat has a different caloric value. These are overall averages for each class.
Even if you ...
- 12.3k
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