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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79 views

Trichloroacetic acid aqueous solution

I have bought some anhydride of trichloroacetic acid (TCA) and would like to prepare an acidic solution. My problem is, that I don't know how much "powder" to mix with how much water to produce an x% ...
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92 views

Does the amount of solute affect rate of solvation?

I know that in order to increase the rate of solvation, you need to increase how often solute and solvent particles come into contact. You can do it by: agitating the mixture increasing the surface ...
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Thickening and/or slowing evaporation of IPA-based ink

The conundrum I have a security printing ink that I make by adding an IR-absorbing dye to a 50/50 mix of Isopropyl Alcohol and distilled water. The ink solution is pale green but dries virtually ...
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102 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"....
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1answer
42 views

What is the minimum operating temperature of chemical hand warmers?

I have been looking at chemical hand warmers such as Hot Hands, Grabber and HotSnapZ. Unfortunately, I cannot find a minimum operating temperature for these types of devices. Logic tells us that they ...
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1answer
369 views

Calculate pH at equivalence point [closed]

Calculate the pH at the equivalence point of a titration of 62 mL of 0.1 M $\ce{CH_3NH_2}$ with 0.20 M HCl. The $\ce{K_b}=4.4\cdot10^{-4}$. At the equivalence point, the moles of CH3NH2 equals the ...
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57 views

Will hydrogen chloride dissolved in ethanol react with magnesium?

Magnesium will react with aqueous HCl to form magnesium chloride and hydrogen gas. Simple. But I've just read in my textbook that HCl in a solution of ethanol no reaction will take place. There is no ...
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1answer
165 views

How to prepare a Gaussian input file for a binary solvent?

The UV absorption energy spectrum of a molecule has been recorded experimentally using binary solvent (DMSO:Water=9:1 v/v). I am trying to calculate the absorption energy of the same molecule using ...
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66 views

Can a solute be physically filtered out of a solvent?

Suppose that I have a substance dissolved in water. I then pour the solution into a filter. The filter's pores are large enough to allow the passage of water, but not the passage of the substance. In ...
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38 views

Gas Molecules in water and Henry's law

I have been doing a little thought experiment and I am not able to reach a satisfactory answer and was wondering if I could get some ideas here. According to Henry's Law, we know that the amount of a ...
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25 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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76 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
128 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 ...
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1answer
591 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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27 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 ...
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802 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
53 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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84 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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14 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
41 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
511 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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29 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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1answer
193 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
92 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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37 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'...
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1answer
44 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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317 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 ...
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72 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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1answer
59 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
94 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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1answer
123 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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2answers
59 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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349 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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56 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 ...
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2answers
290 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 ...
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3answers
1k 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?
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1answer
1k 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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47 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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1answer
57 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 ...
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2answers
129 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 ...
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1answer
86 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, ...
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1answer
74 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
46 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 ...
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4answers
1k 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 ...
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1answer
54 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?
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233 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 ...
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2answers
134 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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52 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. ...
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54 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
213 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 ...