10 votes
Accepted

Why cookies don't soak linearly in function of temperature?

A cookie is roughly starch granules held together by sugar and sometimes fat. At higher temperatures this matrix dissolves faster, and this makes it fall apart quickly. However, at higher temperature ...
Anders Sandberg's user avatar
8 votes

Why is the mole an SI unit?

Chemists measure quantities of material in moles because the progress and outcomes of a chemical reaction may depend on having a well-understood stoichiometry among the constituents. If you want to ...
rob's user avatar
  • 88.6k
7 votes

Why is the mole an SI unit?

The SI is not comprised of the minimal possible number of fundamental dimensional constants. In fact, it is chosen to be fairly redundant, which tends to be somewhat useful for experimental practice. ...
Níckolas Alves's user avatar
6 votes

Why is the mole an SI unit?

In fact, pretty much every unit of measure can be expressed as other units if we wish. Temperature can easily be expressed as average energy. In the original CGS system of electrical units, the unit ...
RC_23's user avatar
  • 8,815
5 votes

Conservation of water?

The number of water molecules is certainly not constant, because chemical reactions can create or destroy water. A simple example is metabolism of Glucose, which creates water. $C_6H_{12}O_6 + 6O_2 \...
Allure's user avatar
  • 20k
4 votes

Conservation of water?

You might have observed in a Science class at school a simple example of the number of water molecules changing , the electrolysis of water. An electric current is passed through water and oxygen gas ...
Farcher's user avatar
  • 94.9k
3 votes

Conservation of water?

The new question you've asked is one of geology, which means the details are a bit fuzzy. It is known that water is lost over time from the atmosphere. It is believed that "... the Earth lost ...
Cort Ammon's user avatar
  • 46.5k
3 votes

Conservation of water?

Is the total number of water molecules on Earth exactly constant ? No, because of the various chemical reactions that consume or produce water molecules. Is the total number of water molecules on ...
gandalf61's user avatar
  • 50.2k
3 votes

Why is the mole an SI unit?

Honestly, I'm surprised that this is the one that you are objecting to. I personally have a problem with the candle (luminous intensity), since it is not really tied to something physical but rather ...
Poisson Aerohead's user avatar
3 votes

Why is the mole an SI unit?

Mole is base SI unit, so it's fundamental, as per Avogadro law, which states that all gasses of same temperature and pressure bounded by same volume - has same number of molecules. Or in terms of ...
Agnius Vasiliauskas's user avatar
2 votes
Accepted

Nature of absorption spectra peaks similar profile in Dimethyl sulfide (C$_2$H$_6$S)

In high resolution any resemblance would disappear. The spectrum shown results from rotovibrational modes. C-H stretch modes have wave numbers of about 3000 cm$^{-1}$. The spectrum at 1000 cm$^{-1}$ ...
my2cts's user avatar
  • 23.8k
2 votes

Can a homogeneous chemical solution really not be split by centrifuge?

The issue is that salt ions, while heavier than individual water molecules (they are after all an ion surrounded by coordinated molecules) are not much heavier, and the diffusion rate due to thermal ...
Anders Sandberg's user avatar
1 vote

Conservation of water?

In addition to all the other answers, the earth is constantly being bombarded by small meteors, many of which will contain small amounts of water.
David White's user avatar
  • 12.1k
1 vote

Conservation of water?

Every time you turn on your gas heating you create water due to the combustion reaction $CH_4 + 4 O_2 \rightarrow CO_2 + 2 H_2 O$. Similar when you burn wood or drive your car. There are other ...
KDP's user avatar
  • 1,377
1 vote

Why is the mole an SI unit?

Just like the meter is a unit for the fundamental quantity of lenght, kilogram is the unit for the fundamental quantity of mass and so on, the mole is the unit for the fundamental quantity of counting ...
Steeven's user avatar
  • 50.5k

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