# 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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16 views

### Is barium peroxide a salt?

I reviewed the definition of salt, a product of base and acid. I found a chemical equation between barium hydroxide and hydrogen peroxide yielding barium peroxide. I also find a journal article ...
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### Find the pH of a solution obtained by mixing 100 ml 0.1m Na3PO4 and 100 ml 0.1 M NaH2PO4. Given that H3PO4: [Κα₁ = 10^-4, Κα₂ = 10^-7, Каз = 10^-11]

So, my query is that since NaH2PO4 is a weak acid, and Na3PO4 is a basic salt, wouldn't they react? Another theory was that since NaH2PO4 is a weak acid and Na3PO4 is a salt of strong acid and NaH2PO4,...
1 vote
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### Why do some powders form powder-filled blobs in a liquid?

e.g., why does this happen? (I think in the picture, it's flour mixed with water. I've seen examples of this with many different powders mixed in liquids, usually water.) What has happened at the ...
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### Calculate the mass of a non-volatile solute (molar mass 40 g mol–1) which should be dissolved in 114 g octane to reduce its vapour pressure to 80% [closed]

in the answer to this quesiton, a modified formula is used where we ignore the moles of solute in the equation for mole fraction, if we didn't what would be the answer and which one is correct
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### In an unsaturated solution, is the product of ions still equal to Ksp?

Suppose I have a solution of a sparingly soluble compound, and consider its solubility in g/L. If I have less g/L of solution than that amount, it means the solution is unsaturated, but what happens ...
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### Can you clearly explain what osmotic pressure is?

There are two main questions I'm struggling to get my head around. What exerts osmotic pressure? Is it the molecules of the solvent (water) or solute particles (sugar) ? Where is it exerted? On the ...
20 views

### Why can we calculate the molar mass of a non volatile solute using lowering in vapour pressure?

Apparently it is possible to calculate the molecular mass of a non volatile solute using relative lowering of vapour pressure using the equation: Where P is the total vapour pressure of the solution, ...
1 vote
43 views

### What does it mean for a substance to be "sparingly soluble"?

I have trouble understanding what solubility means. Merriam-Webster defines it as follows: 1 the quality or state of being soluble 2 the amount of a substance that will dissolve in a given amount of ...
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### Calculate the volume (in mL) of 0.200 M CaCl₂

Trying to calculate the volume (in mL) of 0.200 M CaCl₂ needed to produce 2.00 g of CaCO₃ (s). There is an excess of Na₂CO₃. Molar Mass of Carbon Carbonate = 100.09 g/mol. I am getting the answer ...
1 vote
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### Increasing energy density for flow batteries with water based electrolyte?

Given a flow battery with a water based electrolyte, would it be possible to increase the energy density of battery by precipitating the redox active species from the anolyte and catholyte solutions? ...
1 vote
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### History of Azeotrope (azeotropic mixtures)

I'm currently researching the history of azeotropic mixtures for an essay, and I've come across some interesting information. The term "azeotrope" was coined in 1911 by English chemists John ...
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### Is this evidence that solubility of sodium bicarbonate<sodium carbonate?

Someone introduced $\ce{CO2}$ into saturated $\ce{Na2CO3}$ solution, and observed that white precipitate is produced. He therefore claims that $\ce{NaHCO3}$ has less solubility than $\ce{Na2CO3}$. His ...
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### Is it possible to make acids and bases in amphiprotic solvents other than water [closed]

In such solvents, could there be chemicals which could donate/accept protons, and if so could their solutions display acidic/basic properties?
1 vote
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### Iodine solution concentration

I am planning to make 1L of 0.005M iodine solution from KI and I2. I have found instructions that say to use 2 g of KI and 1.3 g of I2 but no explanation why exactly this particular amount. I also ...
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### 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 ...
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### Why Green Solution After Putting Bismuth Antimony in Nitrogen Acid

I am in a physics lab studying dislocation, and we submerged a bismuth antimony sample in nitrogen acid (about 50% concentration, if I remembered it right) as the first step to etch it. There were ...
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### How to figure out concentration of ingredients in solution? [closed]

I have a solution that contains 3 inactive ingredients: ethanol, propylene glycol, purified water and 5% of an active ingredient. What would be the smartest way to figure out the concentrations of the ...
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127 views

### What solvents can I use to dissolve Epichlorohydrin rubber and Chloroprene Rubber

I am working with Epichlorohydrin and Chloroprene Rubbers and I would like to cast films of 2 mm at most. The solvents I have in my lab are DMSO, THF, DMF, Acetone, Ethanol and Propylene Carbonate. ...
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### Vapour pressure and Raoults law [duplicate]

Suppose we take a binary ideal solution having components A and B .... let's say that their mole fraction is 1/3 and 2/3 respectively (for simplicity) Now ... We know that this solution will start ...
193 views

### Why does ethanol decrease viscosity of a high pH carbomer solution more compared to water

Carbomer 407 is made up of acrylic acid that undergoes polymerisation to form a long linear structure. At higher pH, the carboxylic acid functional groups will dissociate to form carboxylate ions. ...
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### Mixing two solutions: how to solve such problems, is there a trick? [closed]

Two containers were filled with salt solutions, and the first container contained 1 liter less solution than the second. The mass concentration of salt from the solution in the first container was 10%,...
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1 vote
120 views

### When does osmosis stop?

In the figure given below:- Since only solvent particles can move through semipermeable membrane, if we manage to keep pressure on both the containers equal say by keeping weights, will osmosis go ...
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### Anti-bumping granules

Anti-bumping granules are usually small stones. I presume that the principle of these granules ensuring smooth boiling, is that it blocks the upward motion of solution molecules. Usually the stones ...
110 views

### Why don't P graphs contradict Raoult's law graphs?

Our teacher gave us the following question: 1 mole each of liquids A, B are mixed in a piston-type vessel and piston is moved slowly and isothermally. (PA0 = 75 torr and PB0 = 25 Torr) Find: (a) ...
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### Does dissolution and crystallization always occur together?

Does dissolution and crystallization always take place simultaneously? Also does crystallization also occur in unsaturated solution but its rate is less than rate of dissolution or is rate of ...
1 vote
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### Concentration term PPM [duplicate]

What volume do we assume when the concentration is written as mass by volume ppm? I mean when mass by volume percentage is say 20%, we can say that 20g solute is present in 100 ml solution. So if it ...
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1 vote
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### Why is it that in a buffer solution the equilibrium concentrations may be assumed to be the initial concentrations? [duplicate]

Considering the Henderson–Hasselbalch equation, $$\text{pH} = \text{p}K_a + \lg \frac{[\ce{AcO⁻}]} {[\ce{AcOH}]}$$ $$\text{p}K_a = \lg \frac{[\ce{AcO⁻}][\ce{H⁺}]} {[\ce{AcOH}]}$$ Why are the values ...
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1 vote
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### Why does the melting point of hexafluorosilicic acid differ that much in these two solution concentrations?

From the Wikipedia article for hexafluorosilicic acid: Melting point: ca. 19 °C (66 °F; 292 K) (60–70% solution) $<$ −30 °C (−22 °F; 243 K) (35% solution) What's the reason for this huge ...
61 views

### Why do laundry detergents go bad?

Common lore on the internet is that liquid laundry detergents go bad 1-2 years after they are purchased. Is this true? I'd like to understand the chemistry behind this. This is the laundry detergent I ...
53 views

### How can a volatile solvent make an ideal solution with a non-volatile solid solute?

I ask because to make an ideal solution the intermolecular forces between the molecules of solvent and solute respectively should be similar and after mixing they should also be similar to what they ...
1 vote
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### Are all salts completely dissociated in solution when put in smaller amounts than their molar solubility?

From what I understand, the solubility is given in terms of molar solubility (or $\pu{K_{sp}}$), from which it can be easily calculated). Indeed, the saturation point represents the maximum amount of ...
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1 vote
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### How to prepare solution of liquid reagent of the given molar concentration?

I have a liquid reagent with molecular mass $M = \pu{294.08 g mol^-1}.$ I'd like to prepare $V = \pu{400 ml}$ of solution of that reagent with a concentration $c = \pu{100 mM}.$ Does it mean I have to ...
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### Why causes the curvature of the line in pressure-composition graph?

I have been studying about liquid solutions and came across these graphs. From the first graph it is evident that the solution considered has been assumed ideal as there is no deviation from ideal ...
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### What is the significance of semipermeable membrane in osmosis? [closed]

My teacher said that semipermeable membrane allows passage of only selected particles and then said that it is required for osmosis but I cannot totally understand the main function of semipermeable ...
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### What is the relationship between solutions and changes to states of matter?

For example, when liquid water evaporates, my instinct is to say that of course it's become gas, but I'm a bit unsure because, if I understand correctly, evaporation occurs because air dissolves the ...
63 views

### Can you infer toxicity of an ionic compound based on the toxicity of its ions in other configurations?

Suppose I have two ionic compounds: "NaY" and "XCl". If these were both 'safe' to eat, would it be true that ...
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### Watercolor pigment conundrum - can a change in ionic profile induce flocculation?

A client of mine has installed an ion exchange water purifier to de-harden her tap water. After that, however, she noticed that it has negatively affected her watercolor painting. From what she ...
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### Why is solubility affected by temperature? [closed]

Why when we raise temperature generally a bigger concentration of a soluble gets dissolved in a inorganic solvent?Is there a quantum mechanical reason why this is happening?
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### DIY Turbidity Standards?

I am trying to help my high school chemistry class make their own turbidity standards to calibrate the arduino turbidimeters they are making. Last year we tried calcium carbonate as it makes a cloudy ...
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### 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, ...
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1 vote
103 views

### Does decreasing pH decrease solubility of adipic acid?

I added 3 grams of adipic acid to 150ml deionized water with heating + mixing until it was completely dissolved. This was then boiled and cooled to allow crystals to form. The maximum amount of adipic ...
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