All Questions
44
questions
2
votes
4
answers
172
views
How can the Kw of water be constant?
I know in neutral solution, $\ce{[H+]}= \ce{[OH-]}= \pu{1.0 x 10^-7}$.
However, let’s say I add an acid like HCl. This will increase $\ce{[H+]}$, therefore it’s no longer $\pu{1.0 x 10^-7}$, but is ...
- 41
3
votes
0
answers
45
views
What is the goopy substance that forms before CaCO3 precipitates?
I do a lab where we mix a solution of sodium carbonate with a solution of calcium nitrate. As expected, calcium carbonate (white solid) precipitates out. However, if the concentration is high enough, ...
- 49
0
votes
0
answers
357
views
How do I keep my homemade liquid fabric softener from separating?
I have a recipe for a homemade liquid fabric softener that smells good and works great, but I have to shake it every time before I use it. It gets old fast.
The recipe calls for:
12 cups hot water, ...
1
vote
0
answers
57
views
Can addition of a "neutral" salt like NaCl assist pH test strip measurement accuracy in low ionic strength/poorly buffered solutions?
After a web-search, it seems ISAs (Ionic Strength Adjusters) are offered commercially to assist pH electrode/probe measurements. Presumably meant to increase conductivity (without affecting pH ...
- 129
1
vote
1
answer
141
views
Using a pH meter to measure the presence of water in liquid ammonia? [closed]
I intend to do some experiments with building an ammonia-water gas adsorption refrigerator similar to a Crosley Icyball Wikipedia - Icyball. When recharging the icyball, it is important to not ...
- 19
5
votes
2
answers
3k
views
A solution is cloudy at lower concentration and becomes clear at higher concentration. Why?
This might be just an "everyday life science" question. I am a university professor but not in chemistry so please educate me. Today I was adding some floor cleaner formula to water as ...
- 59
-5
votes
1
answer
1k
views
What is the difference between atom and nucleus? [closed]
Atomic nucleus-The atomic nucleus is the small dense region consisting of protons and neutrons at the center of an atom discovered in 1911 by EARNEST RUTHERFORD. Atoms are made up of a positively ...
0
votes
2
answers
1k
views
Why doesn't base/acid reacting with water create a salt?
An acid/base nwutralization will create a salt + water. If one uses water itself as the acid or base, and have an acid/base neutralization, how come that doesn't create a salt?
For example:$$ \ce{HCN(...
- 205
0
votes
1
answer
207
views
Deposition of saturated solution and affect of evaporated water
20g of water is evaporated from 200g of saturated solution of KNO3(aq) at 60°C by heating and the solution was cooled to 20°C. How many grams of KNO3 were deposited? The solubility of KNO3 in 100g of ...
- 3
-1
votes
2
answers
520
views
Effect of water vaporation on saturated solution
At a high temperature, water is evaporated from the saturated solution by heating. What is the solution losing exactly by the fact that the water left the saturated solution? Does it affect its ...
- 3
0
votes
0
answers
50
views
Solubility Product, and it's relation to solubility
In order to remove temporary hardness of water, it is boiled.
On boiling, while Ca(HCO3)2 gives CaCo3(ppt.) , Mg(HCO3)2 gives Mg(OH)2(ppt.).
According to my book precipitation of Mg(OH)2 occurs due to ...
- 41
1
vote
0
answers
966
views
Freezing point of solution of Water, Ethanol and Sugar (aka, Limoncello)
I'm looking for a diagram of the freezing point of a water solution depending on its content in sugar and ethanol. More colloquially, I want to know how to balance alcohol and sugar so that my ...
- 111
2
votes
1
answer
972
views
Creating a 10 ppb Lead Nitrate Solution
I’m trying to make a 10 ppb Lead Nitrate solution as part of a concentration calibration step for a Beer Lambert’s Law experiment. I plan on performing a dilution in three steps. The calculations have ...
- 467
1
vote
0
answers
119
views
Is there a difference between hand soap and body soap with killing viruses? [closed]
With the Coronavirus in full swing around the globe, I wanted an answer to this, particularly since my dad has just been diagnosed with Leukaemia.
We can't find hand wash anywhere but instead I just ...
- 119
-1
votes
1
answer
108
views
What formula allows adjusting balance of (Ethyl Alcohol / Water / Caffeine powder) to know concentration for the Caffeine solution?
I am experimenting with different levels of concentrated caffeine solution. The solution has a small percentage of ethyl alcohol, in the $\ce{H2O}$.
Problems encountered too much ethyl alcohol ...
- 45
1
vote
2
answers
448
views
Does adding solutes to water alter its triple point? [closed]
Does adding solutes to water alter its triple point? If yes, how do we find the new temperature and pressure of this point?
- 153
1
vote
0
answers
537
views
What's the density of a frozen ethanol or ethanol solutions?
How can we know what's the density of ice (water), but there's no data on how much is the density of frozen ethanol? (as far as I know)
4
votes
1
answer
274
views
Why is Iron very rare in seawater compared to many other elements?
I don't know the associated technical words to research this question.
There was high presence of Iron in the oceans in anoxic precambrian times, and today copper is 5 times more abundant in the ...
- 573
9
votes
1
answer
4k
views
Why does Dead Sea water feel greasy?
The best explanation I found so far is this:
These salts (magnesium, potassium, sodium, etc.) are responsible for the "greasy" feel of the water.
But it doesn’t say which salts exactly are ...
- 201
3
votes
0
answers
1k
views
Calculating total volume mixing NaCl and water
I'm (as a non chemist) trying to calculate the the volume of a NaCl solution. The problem is that I know the volume of water prior to mixing in NaCl, but I want to know the volume of the solution ...
- 131
1
vote
1
answer
2k
views
How do hydrogen bonds break the ionic bonds of a crystal lattice? [duplicate]
In the case of water dissolving sodium chloride. I was under the impression that hydrogen bonds were much weaker than the ionic bonds in sodium chloride, so how do they overcome the ionic bond ...
- 51
1
vote
0
answers
365
views
Mutual solubility of water and hexane [closed]
The question says that
the value of mutual solubility of water and hexane is small. Consult bibliography to find it out.
I can't find it and I'm also concerned as to why the question doesn't ...
- 477
0
votes
1
answer
935
views
Extract ammonium sulfate from water
What is the best method to extract ammoniumsulfate from water?
The assignment is as follows:
Manure is being processed and the product left is a mixture between water and ammonium sulfate, ...
1
vote
1
answer
278
views
organic hard surf wax?
I made some organic surf wax with 4 parts beeswax and 1 part coconut oil. The wax turned out to be sticky but had no tack.
I'd like to make wax for warm water that forms a layer of hard bumps on the ...
- 111
4
votes
1
answer
273
views
Liquid that does not spoil for a mineral aquarium
I want to create a decoration - a mason jar "aquarium". I want to take a large mason jar, put some nice mineral specimens in it, fill the jar with liquid and seal it with lid.
I believe I can't use ...
- 41
4
votes
1
answer
6k
views
Explain volume contraction in mixtures of alcohol and water
Could someone explain why volume contraction occurs when you mix an alcohol such as ethanol with water in relation hydrogen bonding and the dipole-dipole forces?
- 49
-2
votes
1
answer
9k
views
I have 6% weight by vol of hydrogen peroxide. How much water should i add to make it 3% [closed]
i read that to bleach hair we should use 3 percent hydrogen peroxide. the bottle i got is 100ml and says 6% w/v h2o2.so how much percentage of peroxide does it contain. how should i dilute it
- 1
3
votes
1
answer
5k
views
Does NaCl reduce the surface tension of water?
Does NaCl reduce the surface tension of water? And why?
For example soap does it, and I was wondering if NaCl does the same.
- 33
1
vote
1
answer
1k
views
Supersaturated gas solution
Can you make a supersaturated gas solution?
As we know solubility decreases when we increase the temperature, So If I do that, will the gas molecules escape the solution or will they stay in the ...
- 329
2
votes
1
answer
8k
views
Does glycerin promote bacterial growth the same as water?
A sodium chloride + water solution draws the water out from bacteria through the process of osmosis.
Would a sodium chloride + glycerin solution have the same antibacterial effect?
If I understand ...
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