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6
votes
3answers
2k views

How much salt (or any other substance one can find in a kitchen) do I need to add to make water boil at 104 °C? [closed]

I've seen some formulas around in other questions and Google searches, but my chemistry is pretty much dead so I have no clue where to find the relevant values to calculate it myself. I just need to ...
1
vote
3answers
333 views

How to determine if an unknown is potassium chloride or potassium bromate?

In class, we were given unknown substances. I've narrowed the possible substances down to either potassium chloride or potassium bromate. We were given several acids, indicators, and other chemicals (...
1
vote
0answers
59 views

Formulation of a suspension of Magnesium Hydroxide

For a school project of mine, I have to formulate a suspension of Magnesium Hydroxide which contains at least 50% of solid matter. This suspension is prepared from Magnesium Oxide 98% with a ...
1
vote
1answer
108 views

Predict melting point of water CaCl2 solution

I'm doing a science project for my school. I experimentally measured the melting point of water-salt solutions, and I want to compare my results to theoretical melting points, but I encountered a ...
0
votes
1answer
98 views

Chemiluminescence of luminol

Recently I have tried to perform an experiment with luminol and hydrogen peroxide (with potassium ferricyanide as the catalyst). Upon googling, I found two ways to conduct this experiment and was ...
5
votes
1answer
58 views

How do you experimentally calculate the ionization constant of the carbonate ion?

Given sodium hydrogen carbonate, $\ce{NaHCO3}$, as well as hydrochloric acid, $\ce{HCl}$, how would you experimentally determine the ionization constant for the carbonate ion, $\ce{HCO3-}$? By ...
3
votes
1answer
3k views

Best way to dissolve/emulsify beeswax and carnauba wax in water-based solution

What I can use to dissolve beeswax and carnauba wax and keep it in an aqueous solution? I do not want to use ethanol or acetone as they are too harsh. I am adding about $\pu{5\%}$ wax to a $\pu{16oz}$...
1
vote
0answers
34 views

Charge Balance and power law?

I've come across a statement in a paper* that's poorly explained, and I can't work out the reasoning behind it. I suspect this is embarrassingly basic, but could anyone please explain the theory ...
3
votes
0answers
104 views

Chemistry Behind TMOS Aerogel

I have found out how to make silica aerogel. Currently, the solution that I need to create to make the gel requires tetramethyl orthosilicate or TMOS. Furthermore, the procedure requires me to make ...
4
votes
1answer
481 views

How can I calculate the molar conductivity of a solution with multiple solutes?

I'm running an experiment mixing 2 different solutions, $\pu{5 mL}$ of $\pu{0.1 M}$ $\ce{NaCl}$ with $\pu{5 mL}$ of $\pu{0.1 M}$ $\ce{KCl}$. I am measuring the conductivity of the total solution in $\...
2
votes
0answers
93 views

Vacuum filtration: will Polymer elements interfere with the vacuum?

I am doing an experiment with vacuum filtration, where a Nylon filter is used to create a membrane (marked in pink in the picture attached). When I use the membrane, it frequently breaks in the ...
0
votes
1answer
3k views

Solubility of potassium nitrate and potassium chloride

Why more water is needed to dissolve potassium chloride than potassium nitrate of equal amount? Is it to do with the reaction that occurs when the compounds dissolve or the properties of the compounds?...
4
votes
1answer
799 views

Temperature change and gas evolution for vinegar and baking soda experiment

This is sort of 2 questions in 1, but I think they are related. Could someone please explain why this endothermic reaction doesn't further decrease the temperature when the amount of baking soda is ...
1
vote
2answers
4k views

Why would a solution of FeCl2 appear brown/yellow sort of like FeCl3?

If we prepare a solution of $\ce{FeCl2}$ by dissolving solid $\ce{FeCl2}$ powder in water, supposing the bottle of $\ce{FeCl2}$ was left open for sufficient time, is it possible for $\ce{FeCl2}$ to ...
1
vote
1answer
707 views

How to correctly prepare a standard solution?

Having just spoken to my teacher about the creation of a standard solution, and she suggested one way of doing it, however a previous chemistry teacher had told us a different way of doing it. My ...
0
votes
1answer
1k views

Making artificial sweat

I'm currently working on a chemistry investigation wherein I need to dilute a compound with artificial sweat. I have looked at various forums, including this, which gave answers, but is very outdated. ...
1
vote
1answer
47 views

How to to test the concentration of melatonin in a strong acid?

If a small tablet of melatonin was coated with a substance to ensure a slow dissolution in water and was then placed in a strong acid, neglecting the limits imposed by maximum saturation, it would ...
1
vote
2answers
298 views

Why do increasing concentrations of zinc chloride not linearly decrease the freezing point?

I did an experiment on how different concentrations of $\ce{ZnCl2}$ affect the freezing point of demi water. My results were that till a concentration of about $10\ \mathrm{mol\,dm^{-3}}$ the freezing ...
1
vote
1answer
41 views

Volume expansion from phosphate buffer solution

I want to mix a phosphate buffer at $\mathrm{pH\ 7.2}$ at $20~\mathrm{^\circ C}$. I do this by dissolving $0.0036\ \mathrm{mol}$ of sodium dihydrogen phosphate monohydrate ($\ce{NaH2PO4*H2O}$) and $0....
1
vote
0answers
165 views

Why are Alkali Metal Ions Soluble?

I think the question needs no elaboration. Why are salts containing Group 1A cations extremely soluble in water? I speculate that the reason involves the low charge density of those ions in a given ...
1
vote
1answer
5k views

What will be the reaction between tin (II) chloride and copper (II) chloride?

I just tried conducting an experiment during lunch today. Now, I calculated this reaction 4 days ago dealing with electrochemistry, $$\ce{SnCl2 + CuCl2 -> Cu(s) + SnCl4}$$ Theoretically, I got ...
5
votes
2answers
392 views

How to choose the correct volumes when preparing a dilution series?

Original Question A solution of dye, Amido Black 10B dye ($10~\mathrm{mM}$, $6.165~\mathrm{g\over L}$), as-provided absorbs light much too strongly for measurement of an absorbance value. It is ...
1
vote
1answer
104 views

Can I use fluorescence microscopy with a solution of hydrogen peroxide?

I want to use microspheres which have been dyed with a fluorescent dye for fluorescence microscopy in a solution that has a 1-5% concentration of hydrogen peroxide. Is this possible or will the ...
5
votes
1answer
487 views

Electrolysis of water for demonstration: ideal electrolyte for safety, stability, conductivity, and ease of maintenance

I'm developing a system for educational purposes where electrolysis of water takes place. The aim is to practically show how electrical energy can be converted to mechanical, by electrolyzing water, ...
1
vote
1answer
1k views

How can I make a fairly saturated copper (II) sulfate solution by heating?

I have an investigation to do for my chemistry class. I'm looking at copper complexes and using ammonia to create a precipitate in the copper (II) sulfate solution, then redissolving the precipitate ...
0
votes
1answer
139 views

Precipitation with NaI

I dissolved $\ce{[Pt(NH3)4](NO3)2}$ in water then I added small amount of $\ce{NaI}$ ($1~\mathrm{M}$) to it. Precipitation occurred. I want to know what happened?
3
votes
1answer
1k views

How to minimise solution concentration changes due to evaporation?

Lets say I have a precise solution, and would like to store it long term (up to two years) with as little as possible change in concentration. The volume is 10-100ml. What container should I choose? ...
3
votes
1answer
241 views

Does aniline breakdown in groundwater produce benzene

Can the benzene ring attached to aniline be detached in an aqueous solution (specifically groundwater) under certain conditions? Would the two compounds be detected as separate entities in a ...
1
vote
1answer
431 views

At what temperature will 6 grams of KMnO4 saturate 100 grams of water

I am trying to obtain more $\ce{KMnO4}$ from less amount by crystallization method. If I got the temperature I would easily make the desired amount. If I am choosing the wrong method, please tell me ...
1
vote
3answers
2k views

Identifying MgCl2 or CaCl2 in solution

I have an aqueous solution of either $\ce{MgCl2}$ or $\ce{CaCl2}$ in solution with $\ce{K2SO4}$. There is a white precipitate that forms on the bottom that does not dissolve when $\ce{HCl}$ is added (...
12
votes
3answers
28k views

Differentiation between zinc, aluminium, and magnesium ions in solution

If I have three aqueous ionic solutions in which I know that the cation is $\ce{Al^3+}$, $\ce{Mg^2+}$, or $\ce{Zn^2+}$, how do I find out which is which? I was thinking to add $\ce{OH-}$ in the form ...
1
vote
1answer
6k views

finding cation of unknown salt in solution from precipitate

I should probably add that I was originally given an unknown solid mixture of 2 salts. I separated the insoluble salt out by centrifuging and then decanting. I found that the insoluble salt is $\ce{...
4
votes
2answers
1k views

Diluting down solutions method

I'm designing an experiment and it involves testing various concentrations of solutions, and I will be testing 5 in total. I proposed to make up a stock solution, and distribute it evenly in 5 ...
1
vote
0answers
595 views

Calculating the Molarity of an Ion?

I'm completely stuck on this one - I was doing an experiment in a lab and now I cannot find the molarity of an ion in a solution. I've looked everywhere on the web but after 2 hours of searching I ...
2
votes
2answers
3k views

How to convert sodium aluminate back to sodium hydroxide?

I had dissolved a bunch of aluminium foil in an aqeous solution of sodium hydroxide. The resulting solution consists mainly of sodium aluminate with very little excess sodium hydroxide. What I want to ...
4
votes
1answer
177 views

How do I make a dysprosium chloride solution from dysprosium oxide?

I know that dysprosium oxide is insoluble in water. I was told that I need to add concentrated $\ce{HCl}$ to the compound and then evaporate the $\ce{HCl}$ off. From looking at the reaction equation, ...
2
votes
0answers
59 views

Preparing CdSe electrodeposition bath

What is the best way of preparing an aqueous solution containing 5 mM $\ce{CdSO4}$, 1 mM $\ce{SeO2}$, 0.5 M $\ce{Na2SO4}$ and adjusting pH to 3 by adding 0.5 M $\ce{H2SO4}$? What is the ...
1
vote
1answer
6k views

I have 100 mg of a proteinase K lyophilized powder and I need to make it to a working concentration of 25 mg/mL

So I know that I need to add $4~\mathrm{mL}$ of solution to this powder, which will give me a concentration of the enzyme at $25\ \mathrm{mg/mL}$. What I do not understand is how to decide how much of ...
0
votes
2answers
207 views

Can citric acid protonation produce benzene and water

Is this reaction possible: $\ce{C6H8O7 + 12 H3O -> C6H6 + 19 H2O}$? Considering that the $\ce{H+}$ can be induced by ionization of the citric acid solution the benzene can be produced in this way?
1
vote
2answers
8k views

How is iron(III) chloride changed from solid to solution?

I'm conducting an experiment using iron(III) chloride in aqueous solution, but am also aware that it's usually a solid. How is iron(III) chloride experimentally converted to a solution? And can you ...