Questions related to the physical combination of two or more substances on which the identities are retained and are mixed in the form of solutions, suspensions, and colloids.
Questions tagged [mixtures]
225 questions
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Why do impurities lower the melting point of an isolated substance?
It is known that impurities in a desired isolated product lower the melting point of the mixture, even if the impurities' melting point is much higher than the desired product. Why is that so?
LanceLafontaine
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How does oobleck work?
Oobleck is basically a mixture of cornstarch and water. It has the interesting property of going hard when pressure is applied. For example, it feels like a liquid when you swirl your fingers through it, but it becomes hard for a second if you punch…
ManishEarth
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Is it possible for a compound to be soluble in a mixture of solvents but not the individual solvents?
Some weeks ago one of my friend needed to use turpentine. As a good but ignorant chemist on that point I did some research about it. I found (at the beginning) in the French wikipedia page of turpentine :
"L'essence de térébenthine est un mélange…
ParaH2
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Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?
This answer to the question Pre-mixing cryogenic fuels and using only one fuel tank written by a non-chemist (me) begins with:
At STP:
LOX's boiling point is 90.19 K
Methane's freezing point is 90.7 K
This does not a priori prove that a solution…
uhoh
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Un-denaturing industrial alcohol
I have a question regarding the denaturation of industrial ethanol with methanol to discourage its consumption.
The boiling point of methanol is 64.7 °C, while the boiling point of ethanol is 78.37 °C. Wouldn't it be trivial then, to separate the…
René
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Is enthalpy additive in mixing?
When mixing two fluids of different composition at constant pressure when no heat can escape, is the enthalpy additive?
If not, how to compute the enthalpy of the mixture resulting from mixing two fluids with given composition after equilibrium is…
Arnold Neumaier
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Mixing two containers of each water and ethanol to varying degrees of purity
In the following question, the water/wine mixing problem was recast in chemical terms. However, partial molar volumes can make this a much more challenging problem than it appears on the surface.…
Ben Norris
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Why does the ink on my whiteboard move?
...or at least I thought so, when I saw that the ink that was on my whiteboard last night became really messed up the next day.
The image below shows my whiteboard before (on the left) and after (on the right). The time span was one night.
As you…
rhyaeris
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Is it possible to boil a liquid by just mixing many immiscible liquids together?
In open air, when vapour pressure reaches 1 atm, boiling takes place.
I read that if we add two immiscible liquids together, the total vapour pressure of the 'mixture' is close to $p = p^*_A + p^*_b$, means that the vapour pressure of the 'mixture'…
TheLearner
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Are all homogeneous mixtures just solutions?
Or can there be a homogeneous mixture that is not a solution?
la.vie.en.rose
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What is the carbon dioxide content of a soda can or bottle?
I sort of know how carbonated beverages are carbonated: a lot of $\ce{CO2}$ gets pushed into the liquid, and the container is sealed. There are at least two things I don't know. First, how much carbon dioxide is actually dissolved in the liquid?…
Colin McFaul
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How does dimethylsulfoxide serve as a cryoprotectant?
In cell culture, dimethylsulfoxide (DMSO) is added to prevent the formation of ice crystals which may lyse the cells. Exactly how does dimethylsulfoxide act as a cryoprotectant?
bobthejoe
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Do azeotropic mixtures evaporate proportionally?
Do azeotropes evaporate, without boiling, in proportionate amounts, or does this property describe their behaviour only at boiling point?
Concretely, if 91% isopropyl alcohol/water (by volume, i.e. an azeotropic mixture) is left open at say 25 °C,…
OJFord
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A quick method for separating liquids?
I'm looking for a way to take 3 separate liquids (liquids which function as paint -- they will all be different colors), put them together into a container, and then rapidly separate them back to distinct colors.
I can handle all the electrical…
temporary_user_name
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How to separate paracetamol and caffeine?
How do you separate paracetamol and caffeine using high-school laboratory equipment?
I was thinking about using the fact that paracetamol has a lower melting point (169 °C) compared to caffeine (around 235 °C): I would heat them up till paracetamol…
Jingjie Yang
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