Questions tagged [solutions]
This tag should be applied to questions dealing with solutions of any kind. A solution is a liquid or solid phase containing more than one substance where, for convenience, one (or more) substance(s) called the solvent is treated differently from the other substances, which are called solutes. If water is the solvent, then the more appropriate 'aqueous-solution' tag should (also) be specified.
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How does shock trigger nucleation of gases dissolved in a liquid?
When you drop a bottle of soda, the dissolved $\ce{CO_2}$ starts nucleating. Opening it before it's 'settled' will trigger more nucleation and usually makes a mess.
Why does the shock trigger ...
8
votes
1answer
2k 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 ...
7
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3answers
1k views
What does washing and drying a solution mean?
After combining two solutions, a direction in a 1970s British chemistry book says to wash the new solution with a mixture of baking soda, table salt, and water. Then it says to dry it with anhydrous ...
7
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2answers
986 views
Limitations of Henry's law
Consider the diagram
Henry's law is a gas law that states that the amount of dissolved gas in a liquid is proportional to its partial pressure above the liquid. The proportionality factor is called ...
7
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1answer
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Is calcium chloride an acidic or basic salt?
What I reason:
Calcium chloride is the salt of hydrochloric acid and calcium hydroxide. Calcium hydroxide is usually not considered a strong base, and I believe this is because of it's low solubility. ...
7
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4answers
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Gibbs Free Energy of Solutes and Solutions
Using the equation $$\ce{CaSO4 (s) <=> Ca^2+ (aq) + SO4^2- (aq)},$$ and $\Delta H/\Delta S$ values, calculate $\Delta G$ at $50~^\circ\mathrm{C}$ when the solution is saturated with $\ce{Ca^2+}$ ...
7
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1answer
855 views
Dissolution of Lithium in Methanol
Easy question to kick off my chemexchange membership!
I'm learning chemistry in my spare time, and fittingly for a video art project I'm doing, decided to try a simple inorganic(?) procedure to make ...
7
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1answer
370 views
Periodically oscillating chemical reactions?
I've seen before chemistry demonstrations where solutions are mixed with one another and subsequently where the resulting product goes through periodic color changes: for example blue to orange and ...
7
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2answers
7k views
Proportion of gases filled in cylinder of sea-divers
In my book it is given that earlier cylinder were filled with 2% oxygen and 98% helium. Nowadays it is filled with 11.7% helium, 56.2% nitrogen and 32.1% oxygen.
There are few questions which come up ...
7
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2answers
366 views
How do phase transfer catalysts bring anions to organic phase?
Many anions are quite stable in the aqueous phase, but not so much in organic solvents where its necessary to perform some reaction (usually nucleophilic substitutions). I have heard that crown ethers ...
asked May 17 '17 at 12:30
Pritt says Reinstate Monica
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7
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3answers
2k views
How much calcium hydroxide will precipitate after addition of sodium hydroxide into saturated calcium hydroxide solution?
Below was question 34 in the USNCO 2017 exam:
If $\pu{0.10 mol}$ of solid $\ce{NaOH}$ is added to $\pu{1.00 L}$ of a saturated solution of $\ce{Ca(OH)2}$ $(K_\mathrm{sp} = \pu{8.0 \times 10^-6})$, ...
7
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648 views
Can I equalise osmotic pressure using two different solutes?
I understand that there is a pressure gradient between an aqueous solution, e.g. salty water, and, say, pure water due to osmosis. My question is, is it possible to match or almost match, the osmotic ...
7
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1answer
344 views
Is it possible to have Volume(solution) < Volume(solvent before adding solute)?
I understand the answer to the question "Is it possible to have Volume(solution) < Volume(solvent) + Volume(solute)?" is "yes" -- but it is possible that adding a solute causes the solvent to ...
7
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2answers
4k views
Alkaline glycine buffer molarity
Having never prepared a buffer solution before, I am hoping for a little help in understanding the process.
This method I plan to use calls for a $\pu{0.1M}$ glycine buffer at pH $10.6$. Some ...
7
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2answers
397 views
Apparent contradiction in the type of deviation of an ethanol-water mixture
For a mixture of $\ce{EtOH}$ and $\ce{H2O}$: $\Delta H_{\text{mix}} < 0$ (exothermic) and $\Delta V_{\text{mix}} < 0$ (volume contraction). This means that the unlike interactions are stronger ...
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3answers
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How to dissolve a spider with household chemicals?
Somehow a spider got into the little window that shows the water level on my electric kettle. The kettle doesn't come apart very easily, and it looks like I can't get this part off without breaking it....
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2answers
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Dissolve Silver Oxide
I was looking at how to dissolve silver oxide (in a solvent). I know that monovalent silver oxide will not dissolve in water, but are there any solutions in which monovalent silver oxide will dissolve?...
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5answers
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Difference between solubility and dissolution?
How is solubility different from dissolution? And how are they both different from solvation?
6
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2answers
295 views
What makes some chemicals form steep density gradients in solution?
Caesium chloride and sucrose are both suitable for isopycnic centrifugation, and presumably not much else is. I'm unclear as to the mechanism by which they form useful density gradients. Wikipedia ...
6
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2answers
208 views
Scientific Reason for Salt Solution Gaining Volume
A little background to this question: my mom placed a glass with salt and enough water to just cover the salt in a room to "absorb negative energy" out of the room at her office. It obviously "worked"....
6
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1answer
340 views
When are we justified in making assumptions in questions
The density at $20^\circ\mathrm{C}$ of a $\pu{0.500 M}$ solution of acetic acid in water is $\pu{1.0042 g/mL}$. What is the molality of the solution? The molar mass of acetic acid is $M(\ce{CH3CO2H})=\...
6
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1answer
2k views
Why does concentration of solutions of alkali metals in liquid ammonia change the magnetic properties?
In "NCERT Chemistry for Class XI - Volume II", in chapter "s-block elements", under the topic "Chemical Properties of alkali metals", it is given:
(vi) Solutions in ...
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1answer
427 views
Phase abbreviations for non-aqueous solutions
When writing a chemical equation, how do you indicate that a chemical is dissolved in a non-aqueous solvent?
For example, it would be inappropriate to write
X (aq)
when X is dissolved in benzene, ...
6
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1answer
6k views
Titration of sulfuric acid with sodium hydroxide
$55.0~\mathrm{mL}$ of $0.250~\mathrm{M}~\ce{NaOH}$ is used to titrate $35.0~\mathrm{ml}$ of $\ce{H2SO4}$.
What is the molarity of $\ce{H2SO4}$?
I know that the equation for this reaction is:
$$\ce{...
6
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2answers
72k views
What is the differences between partial pressure and vapour pressure?
Was looking at Henry's law and Raoult's law
constants and there seemto be lots of
equations involved.
Henry's law involves partial pressure and the latter involves the vapor pressure.
Wondering what ...
6
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1answer
38k views
Degree of association, van't Hoff factor and dissociation constant
$\ce{CH3COOH->CH3COO- + H+}$
\begin{array}{c|c c c}
\mathbf{Initial} & \mathrm{1~mol} & \mathrm{0~mol} & \mathrm{0 ~mol} \\\hline
\mathbf{Final} & \mathrm{1-\alpha ~mol}&...
6
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2answers
5k views
Spontaneous explosion of a bottle containing alcohol and milk
A friend of mine gave me a bottle of home-made liquor which is a concoction of pure alcohol and sweetened milk. I accepted his gift happily and then I put the bottle in my cocktail cabinet. After an ...
6
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2answers
262 views
How to calculate the pH of a redox reaction between nickel(IV) oxide and silver?
For the following reaction:
\begin{gather}
\ce{NiO2(s) + 4 H+(aq) + 2 Ag(s) -> Ni^2+(aq) + 2H2O(l) + 2Ag+(aq)}\\
E^\circ = \pu{2.48 V}
\end{gather}
Calculate the $\mathrm{pH}$ of the solution if $E ...
6
votes
1answer
131 views
How Would A Vast Mixture (Like an Ocean) of Ammonia-Water Behave in Terms of Evaporation and Freezing?
First, I'll go ahead and say I'm not very versed in chemistry. My question comes from my interest in planetary-sciences, specifically the speculation that there are likely exoplanets and moons with ...
6
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1answer
73 views
Dissolving to Create a Solution with Ethanol
If at 95% Ethanol can dissolve chemical X at 1mg/1mL then theoretically if you have 500mg of chemical X you can dissolve it in 500mL of $\ce{EtOH}$ to get 1mg/mL correct?
My question is, if you have ...
5
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3answers
11k views
Can there be more solvent in a solute?
Something I know that leads to this question:
Water dissolved in ethanol.
It might sounds weird to say water as a solute. Textbooks always says that solvent is the one present in larger quantity. ...
5
votes
2answers
390 views
What solvent would have the fewest ions?
We know that water auto-ionizes (to a rather small extent).
My question is which solvent would have the fewest ions (or at least fewer ions than water).
I'm thinking that perhaps some kind of ...
5
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4answers
2k views
Why does the degree of dissociation change when we dilute a weak acid even though the equilibrium constant is constant?
$K$ represents the ratio of concentrations of molecules in a solution at equilibrium, which means that $Q_\mathrm{r}$ (that ratio at any given point) looks to be identical to $K$. In other words, the ...
5
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2answers
496 views
Decrease in temperature of an aqueous salt solution decreases conductivity
Why does the conductivity of a water solution drop as the temperature decreases?
How are these two related?
5
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2answers
1k views
What happens if you mix two insoluble liquids but with the same density? [closed]
Would it make two separate phases? or would it make something like and emulsion?
5
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1answer
20k views
the chemical mechanism for deviations from Raoult's law
Mixtures of ethanol and acetone have vapor pressures that are higher than predicted by Raoult's law, while mixtures of acetone and water have lower vapor pressures than predicted by Raoult's law. Why ...
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2answers
15k views
Why does freezing point decrease on adding impurities?
It is a well known fact that freezing point decreases on adding impurities. I feel that it should increase on adding impurities.
Reason: I have watched this video on supercooled water. It says that ...
5
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1answer
428 views
Why do my equilibrium calculations on this HF/NH4OH buffer system not match those in literature?
I've been trying to reproduce Figure 2 from this research paper (full text available).
The Problem
However I can't seem to get the same values as in the paper. I did the math both by hand and with ...
5
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1answer
19k views
What is the solvent and what is the solute?
This question is and I am learning about mixtures, solutions, solutes, solvents, and other terms related to these words.
I know that a solute is the substance being mixed with or dissolved into the ...
5
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1answer
5k views
What is the lethal dose ( LD50 ) of coffee?
Of course, there are many types of coffee, so I would like a range of lethal dose amounts for the average human, from the mildest of lattes to the most hardcore of espressos.
Pure caffeine's lethal ...
5
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2answers
2k views
Effect of impurities on enthalpy of fusion of ice
When I freeze water with some impurities (1% NaCl by mass), the mixture seems to have a much lower enthalpy of fusion that pure water. The impurities cause the freezing point to depress to 0.6°C. I ...
5
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1answer
888 views
HCl/diethyl ether + Nitrogen?
Just wondering if anyone can tell me why bubbling nitrogen through a solution of $\ce{HCl}$/diethyl ether catalyst would remove said mix from my solution.
My current thought is that the $\ce{N2}$ ...
5
votes
2answers
12k views
What properties does a solvent with a high dielectric constant have?
My professor commented that water has a higher dielectric constant than alcohol.
Okay, but on what basis?
He didn't elaborate; he asked us which one seemed "more electric" and most answered water. ...
5
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1answer
83 views
Distribution coeffecient without concentrations
From what I understand about distribution coefficient is straight from my book — which does not give any practice examples — is that
$$D = \frac{C_\mathrm{A}(\text{ext})}{C_\mathrm{A}(\text{orig})}$$ ...
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2answers
14k views
Solubility in carbon tetrachloride
Which of these substances is more soluble in $\ce{CCl4}$?
$\ce{CH3F}$
$\ce{I2}$
$\ce{Na2SO4}$
$\ce{HCl}$
How do I even solve this kind of exercise?
My guess is that $\ce{CCl4}$ is ...
5
votes
1answer
161 views
What are appropriate techniques to ensure homogeneous solidification of an agar-based aqueous solution?
I am making a T1 weighted phantom for an MRI project. I'm trying to see if I can calculate how much a persons head heats up during an MRI scan. It consists of distilled boiling water, $\pu{7 g/L}$ ...
5
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2answers
3k views
Is lithium bicarbonate an aqueous solution of lithium carbonate?
This question is related to:
Are Lithium bicarbonate and Magnesium bicarbonate both soluble in water?
What type of chemical reaction is this?
How can bromine water be called a solution?
In the ...
5
votes
2answers
6k views
Can a precipitate dissolve upon addition of a diluted acid?
Is it true that precipitates dissolve upon addition of diluted acids?
If a precipitates is dissolve , does it disappear from solution , or any thing else happened out there?
I am just curious ...
5
votes
1answer
347 views
Can acid mine drainage form acid rain?
Can acid mine drainage form acid rain?
Since normal acid rain is formed via combustion of fossil fuels, the sulphur dioxide and nitrogen dioxide are all in the gas phase, whereas in acid mines the ...
5
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1answer
2k views
Why does the Born equation give the Gibbs free energy of solvation rather than enthalpy of solvation?
The Born equation gives the difference in energy required to charge a particle in a vacuum and in solution which results in the work required to transfer an ion from a vacuum into solution. It is ...
