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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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42 views

How do concentrations of nitrate in water samples change over time?

Context: (Not necessary to answer the question) For an assignment I am currently testing two samples of water. One is a pre-contamination sample and the other is a post-contaimnation sample. Between ...
-1
votes
2answers
368 views

KCl + CuCl2 in solution, is there a reaction?

I'm wondering if the reaction of $\ce{KCl + CuCl2}$ in solution (aq) will produce any products (have a net ionic equation/solid precipitate)? Using the metal activity series, I see that potassium is ...
1
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1answer
89 views

Equation to find specific gravity (or density) from a solution of sugar and water

Is there an equation or simple way to calculate the final density of a solution made from x grams of sugar and y liters of water? And would it work in reverse? if we have y liters of water at z ...
0
votes
1answer
60 views

What happens to the gas inside cold drinks as the cold drink is frozen?

According to Henry's law the amount of gas dissolved is directly proportional to the pressure exerted by a gas on the surface of the liquid. And we know if we increase the temperature, the amount of ...
0
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1answer
34 views

Titrations in three equibilums

You have three solutions: 0.1 M solution of a weak monovalent acid 0.1 M solution of a strong monovalent acid 0.1 M solution of a weak divalent acid Each solution is titrated with 0.15 M NaOH. What ...
-1
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1answer
43 views

What's the identity of the crystalline solid in the following reaction? [closed]

A mixture of toluene, benzoic acid, aniline and phenol was dissolved in diethyl ether and extracted with 5% $\ce{NaHCO3}$ solution? This extract was acidified until a white crystalline compound ...
-1
votes
2answers
60 views

Do we consider the dissociation of water when dealing with ion concentrations of a solution?

One mole of hydrated copper(II) sulphate, $\ce{CuSO4 . 5 H2O}$, is dissolved in water. How many moles of ions does the solution contain? 1) 1 2) 2 3) 6 4) 7 The ...
5
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1answer
229 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 ...
0
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0answers
50 views

Deviation from Raoults Law

If I have a mixture of two liquids say X and Y and I also know that this mixture shows significant positive deviation from Raoults Law and that the normal boiling point of X is more than that of Y how ...
0
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0answers
44 views

How can I make a strong coal tar solution that does not stain the bathroom?

I wish to make a strong solution of crude coal tar as a shampoo for scalp psoriasis. Strong means 30% or more. I made a solution with polysorbate 80: 35% coal tar, 50% polysorbate 80, 15% cheap ...
0
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2answers
668 views

How do I find the theoretical pH of a buffer solution after HCl and NaOH were added, separately?

This question is about the theoretical pH of a buffer solution. Calculate the theoretical pH values expected for a $\pu{200mL}$ buffer solution containing a 1:1 ratio of acetic acid and sodium ...
2
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0answers
136 views

What result should I have obtained in these tests? Also, what went wrong? [closed]

As part of a Chemistry practical, I had to five different tests for things, and note down the result. Unfortunately, at least several results were incorrect, and despite hours of research, I cannot ...
4
votes
1answer
133 views

Would ionic compounds dissolve in methanol?

Question: Determine whether liquid hexane ($\ce{C6H14}$) or liquid methanol ($\ce{CH3OH}$) is the more appropriate solvent for the substances grease ($\ce{C20H42}$) and potassium iodide ($\ce{KI}$)....
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0answers
51 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)
6
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0answers
97 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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0answers
101 views

How does the molarity of a solution change on boiling off the solvent?

The dilution equation $$M_1V_2=M_2V_2$$ is an equation that can be used to calculate how adding water can impact the volume and molarity of a solution. So I was wondering if this equation would apply ...
-1
votes
1answer
95 views

What is the stability of Pregnenolone in various mediums? [closed]

I have some pregnenolone powder that I want to dissolve it in to a liquid medium for later human ingestion, some potential medium choices would be: alcohol, fruit juice, water, olive oil. I am trying ...
0
votes
1answer
269 views

Chemical potential of mixtures of ideal gases and the Gibbs-Duhem equation

As is well known for a constant composition system, $\mu$ (symbolizing chemical potential) is equal to the molar Gibbs energy. Using $$ \mathrm{d}G = V\mathrm{d}p-S\mathrm{d}T, $$ we can write $$ \mu =...
2
votes
2answers
90 views

Crystallisation problem

I have an aqueous solution of N,N-dimethylphenylalanine methyl ester hydrochloride and I need to crystallise it as a salt. I'm afraid of increasing the temperature or the concentration of acid due to ...
-1
votes
2answers
221 views

How to make a pH 6.8 Tris buffer?

To preface this, I am a biologist. I need to make a $\mathrm{pH}=6.8$, $\pu{1 M}$ Tris buffer. We have access to Tris base and Tris Hydrochloride. (Unfortunately, none of the fancy Tris compounds ...
1
vote
3answers
256 views

Saturated vs Supersaturated

The way I was told is that a saturated solution contains the maximum amount of solute and a supersaturated solution contains more solute than a solution can hold at a particular temperature. But I was ...
3
votes
1answer
68 views

Flaw in my logic on Henry's Law?

It states mathematically $ p=Kx $ where $x$ is mole fraction of dissolved gas and $p$ is partial pressure of the gas. Dissolution of gases is exothermic, so with increase in temperature, solubility $x$...
2
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0answers
32 views

QM modelling of charge separation reactions

I have a general question regarding the modelling of reactions in which neutral reactants form charged species/ions (in solution). How can one get the energetics approximately right on reactions like ...
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0answers
22 views

Can the solutions for the Briggs Rauscher experiment be made ahead of time and stored?

I will be performing the Briggs Rauscher Oscillating reaction as a part of an investigation into the effect of heat on the antioxidants. This will require 3 solutions to be mixed together, as shown ...
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votes
1answer
30 views

Ethanol in Gasoline

If gasoline with 10% ethanol is stored for a few weeks, will the ethanol evaporate? I have read that to check for ethanol in gas is to add a little water to a container; mark the level and add gas. If ...
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votes
2answers
491 views

Why does acetic acid (CH3COOH) conduct electricity the worst in comparison to HBr, HCOONa and NaNO3 [closed]

Which of the given substances (in an aqueous solution) conducts electricity the worst: $\ce{CH3COOH}$, $\ce{HBr}$, $\ce{HCOONa}$ and $\ce{NaNO3}$? I've found this assingment included in the 2017 ...
1
vote
1answer
226 views

When can a Secondary standard solution be used for standardising something instead of a Primary?

I am writing an assignment on 'Preparing and Using Standard solutions for Use in Analysis in Titrations and Spectroscopy' and one part is asking about primary and secondary standard solutions. I ...
-2
votes
1answer
273 views

Is it advisable to make vinegar at home using acetic acid?

I've taken only a couple university chemistry courses. In the lab, when we always used acetic acid in powdered form, it struck me how when buying vinegar in a bottle from the store, you must be paying ...
2
votes
0answers
2k views

Why is osmotic pressure the best colligative property? [closed]

The osmotic pressure method has the advantage over other methods as pressure measurement is around the room temperature and the molarity of the solution is used instead of molality. As compared ...
4
votes
1answer
57 views

Solubility of oxygen in liquid hydrogen; is anything near 1:2 (molar ratio) possible?

In a question on another Stack Exchange site a proposal was forwarded to premix oxygen and hydrogen in the stoichiometric molar ratio of 1:2 to be used as rocket fuel, as opposed to the standard ...
2
votes
1answer
70 views

Is volume expansion possible upon dissolution of solute?

I am aware that there is volume reduction upon dissolution of ionic solutes, due to the formation of hydrated spheres of aqueous ions where water molecules aggregate around the solute ions. But ...
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2answers
53 views

how to display diffusion to a young audience?

I need to display some science topic pertaining to the atomic bombs, or atomic history in some way to children of approximately middle school level. So I've decided that something interesting to cover ...
4
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1answer
89 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 ...
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1answer
37 views

Dilution calculations

$\pu{5 mL}$ of $\pu{0.012 M}\,\ce{Pb(NO3)2}$ is mixed with $\pu{5 mL}$ of $\pu{0.030 M}\,\ce{KI}$. $\ce{PbI2}$ forms. Calculate the diluted concentrations of $\ce{Pb^{2+}}$ and $\ce{I-}$ ions. I ...
5
votes
3answers
469 views

Calculating the density of a saturated salt solution

Is there a way to calculate the density of a saturated salt solution from the solubility limits or does it have to be experimentally determined? First instinct, is to add the mass of the salt to ...
7
votes
3answers
568 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 $\ce{Ca(OH)2}$ $(K_\mathrm{sp} = \pu{8.0 \times 10^-6})$, ...
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1answer
232 views

What is the logic behind the division into groups of anions and cations in qualitative inorganic analysis? [closed]

I find it very confusing and hard to memorize. Is there a way I can deduce it, like understand how it came or is it just one of a lot of ways you can do it but is the standard one? Also, how does one ...
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0answers
318 views

How to determine the mass of sodium chloride and volume of a 1 M silver nitrate solution necessary to produce a given mass of silver chloride?

Determine how much $\pu{1 M}$ $\ce{AgNO3}$ solution and $\ce{NaCl}$ is needed to produce $\pu{1.25 g}$ of $\ce{AgCl}$. The balanced equation is $$\ce{AgNO3 + NaCl = AgCl + NaNO3}$$ and the molar ...
2
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1answer
173 views

USNCO Question - Determining solute using spectrophotometer

Below is a question from the 2017 USNCO: The concentration of which approximately 0.01M solution could be most accurately determined by a visible spectrophotometer (or colorimeter)? (A) $\ce{Mn(NO3)...
2
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1answer
118 views

Is HDPE affected by long term exposure to methanol?

For at least several years I'be been storing various chloride solutions with methanol as a solute in Nalgene containers, which I believe are made from high density polyethylene (HDP). But recently ...
4
votes
2answers
111 views

How to determine if two calibration curves are parallel, within 5%

I have complex matrices and I need to make sure the matrix does not affect the measurement of my analyte. To do that, I need to prepare samples of my analyte in a solvent and of the matrix reinforced ...
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1answer
54 views

Chemistry of making glass [closed]

To boil glass, the lime and sand mixture of potash was heated and the off gas spent $\pu{125 mL}$ of barley hydroxide solution (density $\pu{1.14 g mL-1}$). The mass of the sediment was $\pu{4.925 g}$....
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1answer
252 views

Why does solvent particles move towards solution when semi permeable membrane is added?

When a SPM is added in between solute and solution the water molecules move towards salt water even though the concentration is same both sides. Why does this happen? According to SPM's perspective, ...
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0answers
65 views

Kinetics of A + 2 B -> C reaction

A reaction $\ce{A + 2 B -> C}$ is carried out in constant volume at $\pu{227 ^\circ C}$. the volume is $\pu{2 L}$. There is no $\ce{C}$ at the beginning. $[\ce{A}]_0 = \pu{0.035 mol L-1}$. $\ce{B}$ ...
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1answer
2k views

pH value of a buffer solution of HClO and NaClO [closed]

So, I have 200mL of HClO 0,64M. I mix it with 0,1mol of NaClO. How should I calculate the pH? My question is about this: should I keep attention about changes made to the solution volume after adding ...
8
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1answer
930 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 ...
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2answers
334 views

Converting mass percentage of a solution into its density? [closed]

Is there a way of converting mass percentage of a solution to obtain its density? (With mass percentage been given and the compounds which are mixed to form the binary solution)
5
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0answers
175 views

Why droplets of water and ethyl alcohol solution freeze weirdly? [closed]

I'm doing a project where I freeze water drops and solutions with water and ethyl alcohol. It's a phenomena where drops create a conical shape at the end of their freezing. But with ethyl drops, with ...
5
votes
1answer
158 views

Is there a paper glue that is NOT dissolved by acetone?

Short version of the question: I need a spray-on glue that will stick paper to wood that isn't dissolved by acetone. Long version: I am trying to glue paper on wood. It's a big sheet of paper and I ...
3
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0answers
321 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 ...