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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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7 views

Preparation of solution with hydrated molecules

I need to prepare a NaH2PO4 solution the preparation protocol says "9,66 g NaH2PO4x1H2O are dissolved in 350 mL of water" but I only have the NaH2PO4 in dihydrated form (NaH2PO4 x 2H2O) what ...
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0answers
9 views

Freezing point lowering for a mixture of many liquids

I have been taught that if I have a solute of molality $m$ mixed with a liquid, the freezing point in lowered by an amount $K_\mathrm{f}\cdot m$ where $K_\mathrm{f}$ is the molal freezing depression ...
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1answer
40 views

How to keep raspberry ketone from forming crystals again after dissolving in alcohol?

I dissolved raspberry ketone 700 mg in 10 ml of 99% isopropyl alcohol. The solubility according to pub chem is 1 g/ml. After dissolving, I added room temperature water to bring the final volume to 70 ...
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1answer
21 views

How dependent is the molal depression constant on the nature of solute?

I've been reading about the molal depression constant (freezing point depression constant) for binary solutions in class. I encountered a problem (see below) in which the constant $K_f$ was to be ...
11
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1answer
478 views

Is there a name for this algorithm to calculate the concentration of a mixture of two solutions containing the same solute?

There is an algorithm called "Mischungskreuz" (German for "x of mixing") that is sometimes taught as a shortcut to figure out the following problem: You have two solutions that contain a solute at ...
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0answers
9 views

Effect of temperature on concentration of ammonia in trichloromethane

By reviewing some literature on the distribution of ammonia in water and trichloromethane, I've found that increasing temperature decreases the partition coefficient of ammonia given that the formula ...
19
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2answers
692 views

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 ...
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1answer
22 views

Conflicting info on TRIS buffer - pH6.8 [closed]

I was about to prepare buffer for milk enzyme and to follow prep method described on bio-rad. But then I became suspicious and came across tons of information that pH6.8 is not in effective pH range ...
2
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1answer
42 views

How to take a sample of a hot salt solution without it precipitating in the cooler glassware due to the difference in solubilities at different temps?

I'm doing an investigation to see the effect of temperature on the solubility product of strontium hydroxide. I made a supersaturated solution left in the oven overnight at 85°C for equilibrium to be ...
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0answers
20 views

Does the mole fraction of a solution change with Vant Hoff factor?

I reason that as mole fraction is a measure of colligative properties, increase in the Vant Hoff factor ( and hence increase in the value of colligative properties) should also leave a mark on the ...
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0answers
10 views

Can factors such as non-chelating ions in solution or the temperature of solution change the d orbital splitting of complexes?

My currently primitive understanding of metal complexes is that the d orbital splitting depends on: Identity of central ion Charge density of ligand Geometry of complex ion oxidation number of ...
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1answer
32 views

Reactions between Ca(OH)2 and CO2, and Sr(OH)2 and CO2

So I'm doing an investigation, and it involves using supersaturated solutions of Ca(OH)2 and of Sr(OH)2. I notice that there's always a flaky precipitate formed on top. I need to know about the ...
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4answers
178 views

Why does the degree of dissociation change when we dilute a weak acid even though the equilibrium constant $K$ 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 ...
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0answers
19 views

Is the analyte included in the ionic strength equation?

I don't quite understand the calculation for ionic strength of a solution. The formula includes the concentration and charges of the ions in solution, however, is the analyte (whatever we're trying to ...
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0answers
26 views

Volume change in positive deviation from Raoult's Law

Let us take a mixture of ethanol and acetone as an example. When ethanol is mixed with acetone, the hydrogen bonding between ethanol molecules gets disturbed as actone molecules get in between the ...
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1answer
35 views

How do I make a solution of spinach to titrate with pottasium permanganate? [closed]

My teacher said something about straining it but I didnt quite get it
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0answers
28 views

Separating NiCl2 and CoCl2

My undergraduate lab is currently doing a project in which we have to separate inorganic compounds from organic compounds, identify each compound, and quantify how much of each compound there is. We'...
0
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1answer
36 views

Ionic factor of glucose? [closed]

I am trying to find the $K_\mathrm{b}$ for 50 g of glucose dissolved in 1 kg of ethanol, given the change in boiling point is $\pu{2.2 °C}$. The molality is therefore 0.278. But what is the ionic ...
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3answers
45 views

An aqueous solution of NaCl has a mole fraction of 0.21. What is the mass of NaCl dissolved in 100.0 mL of solution? [closed]

Work mole fraction of NaCl = 0.21/0.21+0.79 If there is 1 mol of total solution, there will be 0.21 mol NaCl and 0.79 mol H2O 0.21 mol NaCl = 12.27 g 0.79 mol H2O = 14.23 g this would yield a ...
5
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1answer
69 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 $$D = \frac{C_\mathrm{A}(\text{ext})}{C_\mathrm{A}(\text{orig})}$$ ...
0
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1answer
35 views

How to measure the electrical conductivity of a substance? [closed]

Suppose you are given these substances: $\ce{NaOH(aq)}$ $\ce{HCl(aq) }$ $\ce{C6H12O6(aq) }$ $\ce{NH3(l)}$ Are there rules to figure out how conductive each compound is? Is it based on ...
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3answers
57 views

Solubility of solids in liquids

How does crystallisation happen and why? I have been told that when a solid is dissolved in a liquid solvent, an equilibrium is set up between processes of dissolution and crystallisation. But if ...
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0answers
38 views

Why zinc sulphate solubility is higher in ethylene glycol than water?

I'm trying to find saturation point for dissolved zinc sulphate in water and ethylene glycol. Based on my knowledge, water is more polar than ethylene glycol as reflected in its higher dielectric ...
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1answer
36 views

Wouldn't adding a proton acceptor still make a solution just as acidic?

Say if you add NH3 to a solution, and it accepts a proton, it still becomes NH4+ in a solution, which is also acidic. A base should decrease the hydrogen ion concentration in a solution, but how does ...
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2answers
279 views

Decrease in temperature of a aqueous salt solution decreases conductivity

Why does the conductivity of a water solution drop as the temperature decreases? How are these two related?
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2answers
49 views

I am not able to get the exact definition of a solution [duplicate]

A substance which is in larger proportion by mass is called solvent and which is in lesser proportion is called solute. What if the volume of the substance with lesser mass is more. Will it still ...
3
votes
2answers
109 views

Why does coke foam up when I add it to (cold) black coffee (no sugar, no milk)? [closed]

Album of the different gifs detailing this situation: Album of coke-coffee related gifs I thought that the answer would be similar to the ice-cream float situation, but I don't see what in the coffee ...
2
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3answers
179 views

Why do colligative properties depend only on number of solute particles?

Colligative properties depend solely on the number of even though the interactive forces are different for different solute-solvent pairs. So why is the dependence only on the number of solute?
2
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1answer
106 views

Is there any difference between isotonic and isosmotic solution?

Is there any difference between isotonic and isosmotic solution? Can we say isotonic solution do not show osmosis because they have same osmotic pressure?
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0answers
36 views

Can a substance be extracted from solution by adding another substance with a higher solubility?

Suppose that I have a substance X dissolved in water. I then add a substance Y to the solution. Substance Y has a higher solubility in water than substance X, and more than enough of substance Y is ...
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votes
1answer
36 views

What happens to depression when two solutions are mixed? [closed]

Equal volumes of $\pu{1.0 M}$ $\ce{KCl (aq)}$ and $\pu{1.0 M}$ $\ce{AgNO3 (aq)}$ solutions are mixed. The depression of freezing point of the resulting solution (with respect to water) will be (assume ...
3
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2answers
53 views

When making a calibration curve, do we have to use the wavelength at maximum absorbance?

If you are making a calibration curve for $\ce{CuSO4}$ where you plot absorbance against concentration, does the wavelength have to be exactly at the maximum of the peak? Or can it be somewhere else ...
4
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1answer
33 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, ...
0
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1answer
42 views

Why are hydrogen-bonded compounds (such as NH3) excellent solvents for most lab reagents? [closed]

Hydrogen bonds are said to be one of the strongest molecular interactions in nature. Then why can most substances that interact through hydrogen bondig such as water and $\ce{NH3}$ able to dissolve a ...
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2answers
27 views

Binding aqueous solution and oil solution without an emulsion

I am trying to solve this mystery...There is this company called 100% pure who makes lipsticks using fruit extracts as their pigments in their formulations. Fruits pigments are water soluble - so, the ...
8
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4answers
890 views

Ionic compound having highest solubility in water

Which ionic compound has highest solubility in water? I can find CsBr having highest solubility with 1230 g/L at 25 °C. Note: compounds like ethanol are soluble to any extent in water, but they are ...
1
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1answer
33 views

Why do you use acetic acid instead of water to create your standard riboflavin solutions?

I must create my own lab and I was going to use water, however, a similar experiment online says that acetic acid should be used to create my standard riboflavin (vitamin B2) solutions. Why is that?
3
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1answer
80 views

Relation between freezing point depression and vapor pressure

My lab manual defines the freezing point as "The temperature at which the vapor pressure of the substance in its liquid phase is equal to its vapor pressure in the solid phase." It goes on to explain ...
2
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2answers
48 views

What explains the stark white colour of my iodometric titration analyte solution?

During my Advanced Higher (secondary school) investigation, I reacted pure copper with concentrated nitric acid to acquire a copper nitrate solution. This was neutralised with excess sodium carbonate ...
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0answers
38 views

Is awaruite to nickel sulfate possible?

Much time has passed since my basic chemistry and I am trying to determine if an awaruite mine proposed by FPX Nickel Corp ("FPX") might serve as feed-stock to nickel sulfate for battery production. ...
1
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0answers
29 views

How to make rheoscopic fluid using glycol stearate flakes

Rheoscopic fluid can be made by adding mica powder to water. I read that mica powder can settle and condense after sitting around for a long time. So I want to use glycol stearate flakes instead. ...
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1answer
138 views

Doesn't Ostwald's law of dilution contradict Le Chatelier's principle?

By Le Chatelier's principle, increasing the concentration of a weak electrolyte brings out more ions. By Ostwald's dilution law, increasing the concentration of a weak electrolyte brings out less ...
0
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1answer
19 views

Suitable safe cleaning solution for aliphatic urethane

I am looking for a suitable cleaning solution for a sprayed on coating that is an acrylic aliphatic urethane. My end goal would ideally be something that can neutralize rust, whiten and brighten the ...
1
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0answers
24 views

Dependence of Osmotic Effects on Particle Size

van't Hof's equation for osmotic pressure is derived with the assumption, among others, that the particle size of the solute is comparable to the particles size of the solvent. It holds well so long ...
1
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1answer
21 views

Gas solution - State of matter

When a gas is dissolved in water does the state of gas changes ? We write it as aqueous but what is the state that exists ? does it has the properties of gases when it is dilluted ?
2
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0answers
73 views

Why does LDA solution gradually turn dark brown?

LDA (lithium diisopropylamide) solution in THF/hexane gradually turns red-brown liquid. Especially commercially available one is extremely dark red-brown. What makes it brown? I've searched online ...
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1answer
61 views

The density of an aqueous solution

Could the density of an aqueous solution be less than 1g/ml ? For an example, can 0.98g/ml be taken as a density for an aqueous sulphuric acid solution ?
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1answer
38 views

How can iodized oil be made?

I want to combine solid elemental iodine with olive oil, to form an iodized oil - what is called an iodostearic acid or iodooctadecanoic acid, here the double bond in the oil becomes saturated by ...
2
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0answers
46 views

Is there a single word antonym for dissociate? [closed]

Teaching ionic and covalent compounds, and one of the differences is that some ionic compounds will dissociate when dissolved but covalent compounds usually do not (salt water vs. sugar water, just ...
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2answers
91 views

Simple question about mixing two electrolytes [closed]

Suppose we have two 0.1M solutions in water. What is their conductivity and how will it change when we mix them, and why? A) NaCl and KCl: Okay, so both are strong electrolytes and conduct well but ...