All Questions
44
questions
2
votes
0
answers
58
views
Behaviour of oleophobic and hydrophobic object in an oil and water solution
I am wondering what would happen if I put a small (between $\mathrm{5mm}$ and $\mathrm{1\mu}$, density between $\mathrm{1}$ and $\mathrm{2\: g/mL}$) item with both oleophobic and hydrophobic ...
- 51
3
votes
2
answers
3k
views
Can dissolving be a chemical change?
My textbook says that $\ce{SO2}$ dissolving in water produces sulfurous acid, but that seems to be a chemical change. But $\ce{NaCl}$ dissolving in water is not a chemical change. Please explain.
- 441
0
votes
1
answer
385
views
Reduced-pressure (vacuum) evaporation/drying of 15 liters of aqueous solution
I have 15 liters of aqueous solution inside an aluminum stock pot which rests upon a hot plate. I want to reduce the boiling point from 150°C to 100°C using reduced pressure.
What is the most ...
12
votes
3
answers
42k
views
How is dissolving a physical change and not a chemical change?
When salt dissolves in water it dissociates and it is no longer in a lattice structure. The electrostatic forces are no longer there and are replaced by water-ion interactions. To me that sounds like ...
- 519
19
votes
3
answers
60k
views
Why there is no change in water level when salt is added?
Let us say we have one glass of water and after that when we add one or two spoon of salt then we notice that salt dissolves in it but when we measure the water level we found that there is no ...
- 1,491
2
votes
1
answer
449
views
Sugar dissolution test
Is there a way to detect whether sugar is completely dissolved in a cup of water other than looking at the bottom of the cup?
I was wondering if there is a test or something that can be carried out ...
- 21
28
votes
5
answers
17k
views
Why is water "the universal" solvent?
This is an old question that our textbook tried to answer but worsened the situation.
Many things are soluble in water. So many, that studying solutions will always require studying aqueous ones. It ...
- 10.7k
7
votes
1
answer
2k
views
Why do some solid chemicals dissolve better in colder water?
I just discovered that some solid chemicals, such as $\ce{Na2SO4}$, dissolve better in cold water than hot water from here and would like to know if there is any particular reason as to why. Is it ...
- 173
9
votes
2
answers
31k
views
How much does water expand when heated, and does salt affect that?
For this question, assume all things not mentioned are perfectly controlled, all at 14.7lbs of atmospheric pressure, and water is 100% pure of anything not mentioned, with no dissolved air.
Given a ...
- 193
3
votes
1
answer
1k
views
High/low density water solution values
I would like to know what min and max values of densities are achievable with water solutions.
There are some conditions:
1. Normal or close to normal temperature;
2. Non-radioactive solutions/...
- 33
21
votes
3
answers
5k
views
Does freezing a solution with water always cause the water to separate and form the ice lattice?
I'm curious, I was trying to look into the affect of freezing a solution with water even when the solution is completely miscible. I came across something that detailed this regarding salt water and ...
- 293
51
votes
9
answers
519k
views
Why does ice water get colder when salt is added?
It is well known that when you add salt to ice, the ice not only melts but will actually get colder. From chemistry books, I've learned that salt will lower the freezing point of water. But I’m a ...
- 627
4
votes
0
answers
169
views
How do xanthan gum and other hydrocolloids work?
Does anyone know what causes things like xanthan gum to make water into a slimy substance on the molecular level?
- 41
14
votes
1
answer
521
views
Why do some solutions eventually stop boiling and start "popping" as they get more concentrated?
A very long time ago I performed an experiment in my kitchen, part of which was to remove all water from a solution. Unfortunately I don't remember what was in it, but the point is that as the ...
- 271