For questions relating to compounds dissolved in water and resulting reactions.

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2
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1answer
42 views

Thermodynamic favorability of hydration

Of 4-nitrobenzyladehyde and 4-aminobenzaldehyde, which has the higher $\ce{K_{eq}}$ of hydration? $\qquad \qquad$ Steric factors can likely be ignored in this problem since we are dealing with ...
0
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1answer
21 views

Calculate $K_{ps}$ from a galvanic cell

Knowing that at 25°C the following galvanic cell: $\\ Pb~|~Pb(NO_3)_2~1M~||~PbS~saturated~|~Pb$ shows an $emf =0,413~V$, find the $K_{ps}$ of $PbS$. My try: This is a concentration cell based on ...
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0answers
16 views

Identifying probable compound using its colour & reactants

This is quote from OxyChem document on Hypochlorites: Steel tanks in caustic soda service become passivated with a gray-black film forming on the metal. Thereafter, caustic soda at less than ...
3
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1answer
40 views

How does KMnO₄ affect electrolysis?

I'm just blindly experimenting. I tried to dissolve some potassium permanganate in water before performing electrolysis. I can't see much difference. How is $\ce{KMnO4}$ dissolved in water? How does ...
0
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1answer
38 views

What is the pH of a solution of HCOONa and HNO3?

Calculate the pH of an aqueous solution obtained by mixing 20 ml of $\ce{HCOONa}$ 0, 1 M and 5 ml of $\ce{HNO_3}$ 0,2 M. ($K_a$ of $\ce{HCOOH}$ $= 10^{–4}$) My try: The number of the moles involved ...
1
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1answer
25 views

Balancing ionic equations and determining number of ions

There were two questions that I've listed below that I've had troubles on. I got an answer in both, but both of them weren't correct. For the first question, they list the answer to be D and then ...
2
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2answers
25 views

Boiling solutions with two salts

If you dissolve two different ionic compounds (that don't make a precipitate) in water and then boil the solution so all the water evaporates, the salts will re-crystallize. Is it possible that you ...
3
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2answers
63 views

Why put zinc solution in a galvanic cell?

In a galvanic cell with Cu and Zn electrodes, I was taught that each electrode is immersed in a solution containing it's own positive ions. I understand why you need copper ions, so they can gain ...
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2answers
30 views

How can you predict a double displacement reaction with no precipitate?

Is it possible to predict a double displacement reaction between two ions in aqueous solution? I see how you can predict precipitation reactions if you know whether the product(s) is solluble, but ...
5
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1answer
96 views

Acid-base equilibrium of NH4CN

I'm having difficulties understanding this problem. We have in the problem that $K_a$ for $\ce{HCN} = 6.2\cdot10^{-10}$ and $K_b$ for $\ce{NH3} = 1.8\cdot10^{-5}$. Write chemical equations to ...
5
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1answer
102 views

Byproducts of the neutralisation of hydrochloric acid with sodium hydroxide

Given a 1M concentration of $\ce{HCL}$ and $\ce{NaOH}$ here are the pHs: pH of $\ce{HCL}$: 1 pH of $\ce{NaOH}$: 13-14 and of course water has a pH of 7. Here is a reaction that is most likely to ...
1
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1answer
52 views

Calculating Ka values from std. state thermodynamic data

My professor showed us a sample calculation of the Ka value for a strong acid. He used standard state thermodynamic data. I have an issue with this: 1) Wouldn't this give us an understated Ka ...
2
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2answers
28 views

Find the color of the solution

The acid-base indicator methyl red has a $K_{a}$ = $1 \times 10^{-5}$. Its acidic form is red while its alkaline form is yellow. If methyl red is added in a colorless solution with a $pH = 7$, the ...
2
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3answers
35 views

What does the hydrolysis of a salt tell us about its basic/acidic character?

I'm curious to know how basicity and acidity arises when a salt or covalent compound is dissolved in water.
2
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1answer
74 views

Neutralization reaction

Question) Complete and balance each of the following molecular equations (in aqueous solution); include phase labels. Then, for each, write the net ionic equation. (A) $\ce{NH_3 + HNO_3 ->}$ My ...
7
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2answers
318 views

How much can the pH change through dilution?

Consider an acidic solution with Hydrogen ion concentration, $\ce{[H+]}$ of $10^{-5}\:\mathrm{M}$. Since $\:\mathrm{pH} = -\log \ce{[H+]}$ the $\:\mathrm{pH}$ of solution is $5$. Suppose we dilute ...
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0answers
15 views

Deviation from ideal solutions - activities and concentrations

What are some examples of solutions deviating significantly from ideal behavior, and, by extension, showing pHs significantly different from those predicted by usage of concentrations instead of ...
2
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1answer
35 views

Is there a database which give reaction constant?

For instance, I have a chemical reaction like : $$\ce{Fe^{2+} + $0.5$O2 + H^{+} ->Fe^{3+} + $0.5$ H2O}$$ And I would like to use Action-Mass law, but I need to have equilibrium constant for this ...
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2answers
42 views

Reconciling the units of pH calculation

As part of a simulation I am developing I have an acid in aqueous solution represented as a concentration field of mass density (units g/L) at various points in ...
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3answers
65 views

Why does an acid exist when dissolved in water?

Acid is a substance that releases $\ce{H+}$ ions when mixed with water But if it releases $\ce{H+}$ ions the acid will ultimately not exist. For e.g we take the acid $\ce{H2SO4}$. If we add water ...
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3answers
97 views

Why are solutions electrically neutral?

I keep reading that solutions are electrically neutral, but I've never read an explanation. I've read after the fact justifications, such as one problem which asked me to calculate the force of ...
3
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1answer
54 views

In a redox reaction, why does more than one oxidation state of an element form?

Consider the reaction 100ml 10M $\ce{NaOH_{(aq)}} +$ 100ml 10M $\ce{NaHSO3_{(aq)} +}$ 100mL 0.01M $\ce{KMnO4_{(aq)}}$ In the picture posted here, the left columns give information on the Molarity of ...
2
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1answer
109 views

Solubility of p-nitrophenol in various substances?

So I had an organic chemistry lab where we had to dissolve p-nitrophenol in water, dilute $\ce{NaHCO3}$, dilute $\ce{NaOH}$, and dilute $\ce{HCl}$ to test for solubility. The p-nitrophenol dissolved ...
4
votes
2answers
192 views

Do buffers only work for species of the opposite variety? (I.e. weak acids buffer strong bases and vice versa)

I have looked at several sources including Khan Academy, ChemCollective and the answer to a similar question: Can someone please explain buffers to me? However, it is not clear whether buffers can ...
0
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1answer
67 views

How much carbonation is in one liter of commercial fountain coke-cola

From what I understand generally coke is carbonated to roughly 6.2g per liter in bottles and cans, or 3.1 volumes of CO2. I was watching this video because I was curious about how fountain soda ...
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3answers
72 views

Why is a buffer solution most effective when concentrations of salt and acid are the same?

Why does a buffer work most effectively when the concentration of salt and acid is 1:1?
2
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1answer
39 views

Permanent suspension of cocoa powder into water

I have failed in permanently suspending cocoa powder into water. I have tried heat (212'f) and pressure (40 psi) into a sugar water solution (50/50). Also, powdered milk and evaporated milk have ...
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0answers
71 views

How to break down soap and detergents?

I am building a greywater harvesting system. I have all of it designed except one aspect. It is a 3 phase system. The first phase breaks down soap and detergents. The second phase filters the water. ...
3
votes
1answer
60 views

Accuracy of pH meters in MgSO4 solution

I bought a 2 pH meters several months back from Amazon for roughly $10 a piece. I couldn't tell you how they work, but here's the link on Amazon: ...
3
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2answers
73 views

What is the minimum pressure for existence of a liquid solution?

The minimum pressure for the existence of liquid solution is $0.6\;\mathrm{atm}$ $0.8\;\mathrm{atm}$ $0.77\;\mathrm{atm}$ $0.9\;\mathrm{atm}$ Although this seems to be an informative question, I ...
1
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1answer
92 views

How do non-ionic compounds dissolve into water? Into molecules or atoms?

I can't seem to find the answer in google, which is surprising. I'm aware that ionic compounds dissolve into electrolytes. However, when non-ionic sacarose for example dissolves in water, does the ...
9
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2answers
114 views

Why doesn't the boiling point of an aqueous solution depend on intermolecular attraction?

I understand that boiling point is a colligative property for aqueous solutions, and that it empirically depends on the mole fraction of the solute, rather than the identity of the solute. I ...
0
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0answers
386 views

Temperature changes when salts dissolve in water

Please help me! I got this as an assessed investigation question and I really do not know where to start, or how I going to conduct this investigation. I understand that I should include information ...
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2answers
56 views

Stability of transition metals in aqueous solution

Which is more stable in aqueous solution $\ce{Cr^{3+}}$ or $\ce{Mn^{3+}}$? And why? My approach: $\ce{Cr^{3+}}$ should be more stable as the 3d electrons will enter the $t_{2g}$ orbitals. Due to CFSE ...
3
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1answer
47 views

metal salt solutions g/l means hydrate or anhydrous

I want to redo an experiment. They've used Nickel chloride: 40 g/L Nickel chloride can be bought in two forms: anhydrous ($\ce{NiCl2}$) and hydrate ...
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2answers
101 views

Is this a trick question?

Disclaimer: It has been a very long time since I have done any chemistry. My friend posted this question on social media, I've copy+pasted it here: Exactly 16.0ml of a solution A is diluted to ...
6
votes
1answer
1k views

How could alcohol be made into a powder?

In the news recently is 'Palcohol', powdered alcohol, http://www.palcohol.com/home.html that you add to water or existing liquids to make it alcohol. Presumably this would dissolve and break apart ...
0
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0answers
49 views

How can I carry out a titration to identify mercury in wastewater?

First, I would like to do a some form of extraction to only get the mercury, then followed by a titration to identify the concentration or the presence of mercury.
0
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1answer
51 views

Electrolysis of aqueous lead nitrate

When going through one of my chemistry textbooks, I saw that the electrolysis of aqueous lead nitrate led to oxygen being formed at the anode and lead being formed at the cathode. However, in school, ...
0
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2answers
62 views

HF and water miscible?

According to Wikipedia, HF is miscible with water. But isn't hydrogen fluoride a gas at RT and a sensible pressure? What would happen if you just kept adding more HF gas to some water?
0
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1answer
79 views

Zinc Picolinate - Positive, negative or neutral charge?

I'm going to be using a finings agent with a positive charge to remove negative trub from a solution (beer). I would like to keep some chelated zinc in the solution - ideally zinc picolinate - so ...
1
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2answers
578 views

How do I prepare a 5N HCl solution?

I am trying to make 5N $\ce{HCl}$ solution. So far I understood that you need to get the molecular weight (36.5) and divide it by the number of $\ce{H+}$ that react in the acid-base reactions. The ...
3
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2answers
118 views

Heat when dissolving solutes in water

Why do certain solutes dissolved in water release heat and other solutes absorb heat?
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2answers
207 views

How to dissolve steel without affecting aluminium alloy

Disclaimer: I have very limited knowledge of chemistry My problem is the following: I have motorcycle part made from some sort of Aluminium alloy - most probably 6005, 6061-T6 or 7005. And inside of ...
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2answers
28 views

Does removing solution affect a supersaturated solution

Given a mixture of: a saturated solution of a solute in a solvent together with excess of the solute compound as crystalline material. If one were to change the bulk composition of the mixture by ...
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1answer
38 views

Evaporation of a mixture of salts

I was wondering what happens when you boil dry a solution of several salts for example a solution of KCl and NaNO3. Since the ions dissociate I was wondering if the ions would combine randomly upon ...
0
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1answer
54 views

How much water has boiled off when precipitation begins?

Here's a challenge problem I created! None of my students could get it; can you? $25$ grams of table salt (NaCl) is dissolved in $150$ grams of water. The temperature of the solution is raised to its ...
4
votes
1answer
251 views

What is a complete reaction?

For a lab assignment, I combined 10mL of 1M sodium sulfate solution with 10mL of 1M calcium chloride solution. The ionic equation I came up with is: $$\ce{2Na^+ (aq) + SO4^2- (aq) + Ca^2+ (aq) + ...
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1answer
36 views

Two chemistry inquiries

Here is my second question, I know 1000 grams of water is 1 liter. But does the density affect the result? What if the substance is mercury? When you add seed crystal in to a supersaturated solution, ...
3
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2answers
126 views

Problems with precipitation of transition metal solution

I am trying to make a solution of "trace elements"--primarily transition metals-- for use in biological media; bacteria require elements like Cobalt, Molybdenum, iron, etc. in trace amounts. I am not ...