Skip to main content
61 votes
Accepted

Why is chemistry unpredictable?

First of all, I'd ask: what do you admit as "chemistry"? You mentioned thermodynamics as being a field where you have "models to predict results". But thermodynamics is extremely ...
orthocresol's user avatar
  • 71.5k
57 votes
Accepted

Brown stains on skin after working with Tollens' reagent

The stains are due to silver nitrate, the reactive portion of Tollens’ reagent. It is very prone to reduction to metallic silver. If you got it on your hands (a clear signal you weren’t wearing ...
Jan's user avatar
  • 68.3k
53 votes

How do they ensure there is one electron on an oil drop in Millikan's oil drop experiment?

There does not have to be just one electron per drop. Say you have a drop which, in reality, picked up four electrons, another with five and a third drop with seven. None has one electronic charge, ...
Oscar Lanzi's user avatar
  • 59.3k
47 votes
Accepted

Why do research papers mention experimental details in such detail?

Experimental details are very, very important: they are used to ensure that results are reproducible, or at least that is the aim. Let's talk about this specific example of suppliers and sources. One ...
orthocresol's user avatar
  • 71.5k
45 votes
Accepted

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 "...
paracetamol's user avatar
  • 18.7k
44 votes
Accepted

How to differentiate between iron and sodium flames?

Sodium flame is yellow, but all the light is due to two lines in the yellow region. If you look a sodium flame through a purple glass (cobalt glass), the yellow color is absorbed, and you do not see ...
Maurice's user avatar
  • 29k
44 votes

Why is chemistry unpredictable?

Let me contribute two more reasons which make chemistry hard to analyse from a purely theoretical standpoint. The first one is that, viewed very abstractly, chemistry essentially relies on the study ...
Nicolau Saker Neto's user avatar
41 votes

Why isn't pressure filtration popular compared to vacuum filtration?

It's much easier to assemble a system that's safe under external pressure than one that's safe under internal pressure. Convex flasks and tubes resist external pressure better than internal pressure. ...
jeffB's user avatar
  • 1,592
40 votes

Why is chemistry unpredictable?

Parts of chemistry have predictability but the combinatorial complexity of what is possible leaves a large amount of space for things that don't follow the rules Some of the ways chemistry differ from ...
matt_black's user avatar
39 votes

Storing hydrofluoric acid before the invention of plastics

In the original 1771 experiment, Scheele used a very simple setup consisting of a glass retort with a glass receiver (round-bottom flask). Yes, the glass was etched to some degree by the fumes, but ...
andselisk's user avatar
  • 38.3k
36 votes
Accepted

Neutralizing a sulfuric acid spill

First, why other options are not really the options: A: vinegar, being a weak acid, doesn't neutralize sulfuric acid and only dilutes it; B: solid sodium hydroxide, a strong base, does neutralize ...
andselisk's user avatar
  • 38.3k
28 votes

How do they ensure there is one electron on an oil drop in Millikan's oil drop experiment?

The experiment showed all the drops had discrete amounts of charge. That means, the charges weren't all over the place (any random value). They only had specific values. Some had $2$ or $3$ or $4$ ...
Stilez's user avatar
  • 419
26 votes
Accepted

What's this glassware?

The glassware shown is a drying tube. The bulb holds cotton or glass/quartz wool while the tube part holds a drying media such as anhydrous calcium sulfate to keep moisture out of the vessel during ...
A.K.'s user avatar
  • 12.7k
25 votes
Accepted

How would I measure the Carbon Dioxide content in Coca Cola over a period of time?

Measure the change in mass over time of the remaining liquid. Though some water will also evaporate, you can control for that by keeping the humidity near 100%. If you have to be precise, collect the ...
DrMoishe Pippik's user avatar
24 votes
Accepted

Hottest region of Bunsen flame

The question itself is poorly written as given. The diagram should have "regions" and "points." So what seems to be labeled "Region 2" and "Region 4" I would name as "Point 2" and "Point 3" ...
MaxW's user avatar
  • 22.3k
23 votes

Why is chemistry unpredictable?

Predictabilty is essentially determined by the level of detail you need to accurately model the phenomenon you're trying to predict. Models that require little detail to capture the phenomenon of ...
theorist's user avatar
  • 12.2k
22 votes

How was it concluded that the H3O+ rather than H+ is the "acid" ion?

Actually, the initial theories before Lewis suggested that $\ce{H+}$ is the cause of acidity. However, it soon turned up that an ion as small as the nucleus of hydrogen (you may simply call it a ...
N Shultz's user avatar
  • 346
22 votes
Accepted

Conventional heating compared to microwave heating of chemical reactions

Your question about the 'magic' microwave effect is one that I think most chemists who've used a microwave have asked. Anecdotally, some reactions do often just work better when carried out in a ...
NotEvans.'s user avatar
  • 17.2k
22 votes
Accepted

What is the role of ammonium chloride in the workup of a Grignard reaction?

Ammonium chloride ($\ce{NH4Cl}$) is the work-up reagent that quenches the magnesium alkoxide product of the Grignard addition. It is the reagent of choice as it is a proton source without being acidic;...
Waylander's user avatar
  • 22.6k
21 votes

What is the purpose of a boiling stick when heating a reaction mixture?

Boiling chips and boiling sticks are practical solutions to problems chemists face in the lab. When boiling liquids they often observe the the boiling does not happen evenly. Instead of a gentle ...
matt_black's user avatar
21 votes

Why is chemistry unpredictable?

"it seems that every other STEM field has models to predict results (physics, thermodynamics, fluid mechanics, probability, etc) but chemistry is the outlier" This is only partially true, ...
Zhe's user avatar
  • 17.5k
21 votes

Is nitroglycerin synthesis within human digestive system from eating soap possible?

According to the metabocard at HMDB — Nitroglycerin, nitroglycerin is only found in individuals that have used or taken this drug. No known metabolic pathways for glycerin lead to nitroglycerin either....
andselisk's user avatar
  • 38.3k
20 votes

Any substance too poisonous to measure an LD50?

Of course no. Botulotoxin is probably the strongest known, and still its $\rm LD_{50}$ is counted in nanograms per kilogram, which is pretty manageable. Sure, working with such tiny amounts requires ...
Ivan Neretin's user avatar
  • 31.3k
19 votes

Why were elements discovered "out of order" after 1950?

The synthetic trans-uranic elements (the "modern era" elements as you call them) are synthesized by bombarding a certain isotope of one element with a certain isotope of another element with a lot of ...
levineds's user avatar
  • 3,080
19 votes

What would be the effect of adding liquid beyond the calibration mark on a volumetric flask?

If you have plenty of solution and reagents, the solution should be prepared again, because the volume is not the nominal volume written on the flask. However, the proper trick to fill the volumetric ...
ACR's user avatar
  • 41.4k
19 votes
Accepted

Why is carbonic acid often ignored?

Similarly, almost every chemistry experiment or demonstration I've seen was done under air, not some inert gas. I don't think it's too much of a stretch to say that the popular chemistry ...
orthocresol's user avatar
  • 71.5k
18 votes
Accepted

What is the scientific term to describe the operation of a bong?

I think the term describing the initial process of separation of the solid phase (dust particles) from the gas phase via bubbling is a wet scrubbing process. On an industrial scale, it's more ...
andselisk's user avatar
  • 38.3k

Only top scored, non community-wiki answers of a minimum length are eligible