This tag should be applied to questions relating to the theory, design, techniques or performance of chemical experiments. This includes but is not limited to theoretical structures, expected products, thermal calculations, and empirical analysis. Additional tags should be applied to narrow down the ...

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3
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1answer
104 views

Thermodynamics and Coffee

Heyo, I'm sure you all know of the experiment where you take a mixture of ice and water, plop some salt in there and the temperature of the solution progressively drops. The salt increases the entropy ...
1
vote
2answers
14 views

Why are hollow cathode lamps used for atomic absorption spectroscopy?

In 1955, it was proposed that hollow cathode lamps are good emission sources for monochromatic radiation, and thus for atomic absorption spectroscopy (AAS). In looking into the topic, I've read that ...
4
votes
1answer
30 views

Instrumental methods of analysis

I am taking the instrumental methods of analysis course. Our job is to find the unknown mass of $\ce{Fe}$ which is added, by measuring the absorbance of different solutions with ortho-fenantroline. ...
4
votes
1answer
33 views

What mechanisms might make a substance travel different distances on the same TLC plate?

When doing TLCs to monitor reactions, it is considered good common practice to not only spot the reactants and the reaction mixture (likely after some mini-workup), but also to include a ‘cross-spot’: ...
3
votes
1answer
42 views

Effect of impurities on enthalpy of fusion of ice

When I freeze water with some impurities (1% NaCl by mass), the mixture seems to have a much lower enthalpy of fusion that pure water. The impurities cause the freezing point to depress to 0.6°C. I ...
1
vote
2answers
41 views

How can I turn Natural gas from liquid to gas?

I hope i am not too off topic, couldn't find a more suitable stack-exchange forum for this, if there is a better one, please point me to it, Well my question is the following, I am working on a ...
1
vote
2answers
29 views

How do I create azeotrope mixture?

I want to decrease the boiling point of a compound. So I need to create an azeotrope mixture from two or three compounds. Where can I find out how make it?
3
votes
1answer
27 views

Practical question about rotovap solvent collection

This is a practical question about the use of rotary evaporators ("rotovap"). So I'm asking for answers from people who actually use the things. A rotovap typically uses a cold condenser to condense ...
3
votes
1answer
36 views

How can I measure the internal temperature of a solid metal?

I’m heating up several metal blocks as part of an experiment to determine their specific heat capacities. In a nutshell, I’m heating the blocks of known mass to 100 °C, then adding them to an ...
3
votes
0answers
19 views

Will the Sulfur-Iodine cycle and Haber Method work at lower pressures and temperatures?

I have a yearlong research project next year in my senior year of high school in which we have to make some product or prototype to solve some issue. My interest was in the Liquid Fluoride Thorium ...
2
votes
1answer
23 views

Decomposition of hexaurea-chromic-chloride-trihydrate

I am sitting over a TG diagram of the decomposition steps of hexaurea-chromic-chloride-trihydrate ($\ce{[Cr(CO(NH2)2)6]Cl3 \cdot 3 H2O}$) and cannot really make sense of the products it might ...
0
votes
0answers
22 views

Stirring the reaction between hydrochloric acid and a powdered substance

For an experiment, I'm adding several substances (as powders) to hydrochloric acid, and measuring the temperature changes to calculate enthalpy. However when adding the powders, the mixture requires ...
3
votes
1answer
28 views

How to lose as little heat as possible to the surroundings from an endothermic reaction?

For an experiment, I'm adding several substances (as powders) to hydrogen chloride, and measuring the temperature changes to calculate enthalpy. What is a container I could perform it in (other than a ...
4
votes
2answers
114 views

Why use a salt bridge at all in an electrochemical cell?

I was reading about electrochemical cells and I really don't understand why a salt bridge is needed. Can't you just combine the solutions? I've found a lot of webpages explaining electrochemical cells ...
-1
votes
1answer
93 views

Experimental difficulty with the iodine clock reaction

I did the iodine clock reaction using sodium metabisulfite and potassium iodate. As I understand it, increasing concentration is supposed to speed up your reaction rate. I did 10 trials. The first 5 I ...
0
votes
1answer
29 views

Spin coat of Graphene oxide on glass slides

I would like to spin coat Graphene oxide on the glass slides and intend to have a thickness of 100nm/0.1micrometre. May I know what is the amount of Graphene oxide to be poured onto the glass slides, ...
2
votes
0answers
34 views

How to store distilled water

How can I store distilled water without introducing impurities? I'm going to be doing so electrical studies of pure water and ice and I need a way of keeping the water pure during the experiments. ...
3
votes
2answers
45 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 ...
6
votes
2answers
121 views

In which country is it allowed to practice non-clandestine amateur chemistry?

I travel a bit so am flexible where I live, and have taken a recent interest in chemistry to try to gain an understanding of physical reality. I find learning from textbooks to be good, but want to ...
4
votes
1answer
79 views

Is there an experiment that visibly shows the effects of metastability?

I am attempting to create an experiment to show the effects of metastability to a public audience and get people excited about science. More specifically, I am wondering if there is any sort of liquid ...
1
vote
0answers
48 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 ...
0
votes
1answer
22 views

Sulfur Doped Titanium Dioxide

I'd like to know why my $\ce{TiO2}$ sol gel did not get coated nicely on my 200 gsm fiberglass? Here my solution, 5 g of tween 80, 40.15 ml isopropanol, 3.4 ml titanium isopropoxide, 0.62 ml sulphuric ...
4
votes
1answer
47 views

How to remove a stuck stopper from a flask

I had a question about how about how to remove a stopper that has been stuck in the neck of a 100 mL round bottom flask since I forgot to wipe the neck of the flask. A salt was formed in the 100 mL ...
1
vote
1answer
29 views

Will trenbolone acetate in the presence of methanol yield trenbolone acetate if distilled water is subsequently added thereafter? [closed]

I have 2 grams of trenbolone acetate. I was told to add it to 20 ml of methanol. Then wait until it is fully dissolved. Then distilled water is to be added yeilding a precipitate that is supposed to ...
3
votes
1answer
75 views

Why did the solution turn green?

I mixed L Arginine with l Citrulline in Hibiscus and green tea water which was red in color. Once the red liquid hit the mix of powdered Aminoacids the solution changed green. Can someone tell me why? ...
1
vote
1answer
206 views

How to calculate the theoretical yield of a Diels-Alder reaction?

A Diels-Alder reaction happens between 9-Anthracenemethanol (208.26 g/mol) and N-Methylmaleimide (111.10 g/mol). I'm using 0.069 g 9-Anthracenemethanol (0.033 mol) and 0.11g N-Methylemaleimide ...
11
votes
7answers
5k views

How can 30 ml of water be heated in less than 10 seconds?

How is it possible to heat a tiny amount (30 ml)[1] of water to a high enough temperature to make a coffee, in less than 10 seconds and possibly instantly? Most heaters that I know of heat water ...
3
votes
1answer
32 views

Solve this mole fraction calculation with incomplete information

I am currently trying to solve a problem that seems quite simple at the beginning but the complexity reveals itself soon thereafter. The problem is the following: You mix a known mass of water ...
5
votes
1answer
160 views

Acetone and Sodium Hydroxide

I have put in a beaker acetone and sodium hydroxide solution (approximately 1M $\ce{NaOH}$) and didn't see any colour change for 1 day (actually, it was transparent, no colour). After almost 2 days, ...
2
votes
1answer
36 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 ...
2
votes
2answers
45 views

Open data in chemistry?

I am a student in computer science, which is a field where sharing research data and source code is very very much recommended. I am looking for sites where data from chemistry experiments could be ...
9
votes
4answers
2k views

How pure NaCl is typical table salt? How is it purified?

How pure $\ce{NaCl}$ is typical table salt? Is it pure enough for research-level experiments in chemistry? How is $\ce{NaCl}$ purified if need to be?
3
votes
1answer
100 views

Is it possible to chemically treat grass to make it digestible?

Is it possible to chemically treat grass after "harvesting" it to make it digestible by humans? I know we can "eat" grass, but we can't break it down in our stomachs. If there is some chemical ...
2
votes
1answer
45 views

Friedel-Crafts synthesis - How is HCl produced?

In the mechanism for the acetylation of bromobenzene, how is $\ce{HCl}$ gas produced? The reactants are acetic anhydride, bromobenzene, $\ce{AlCl3}$ and dichloromethane. Initially, ...
-1
votes
2answers
58 views

Concentration of hydrochloric acid for electrolysis?

How much hydrochloric acid (maximum) should I use to do electrolysis of water, and how much amount of voltage should I use to get the maximum of hydrogen and oxygen?
5
votes
1answer
102 views

Why are potentials of cells with magnesium electrode always lower than expected?

I have prepared the 1M water solution of magnesium acetate. Then I placed $\ce{Mg}$ and $\ce{Cu}$ electrodes in it. I predict there such reactions take place: $$\ce{Mg-2e^- \rightarrow Mg^{2+}}$$ ...
0
votes
1answer
15 views

Replacement For RF sputtering

In my experimental work, I'm following an article. It said that: A 30 nm ZnO seed layer was deposited on the glass substrates by RF sputtering of a ZnO target at room temperature. But I haven't ...
1
vote
1answer
166 views

How to cheaply extract iodine from an alcoholic solution?

I have an alcoholic solution of iodine. My goal is to extract the pure iodine without using rare or expensive compounds. How could I do this?
2
votes
1answer
50 views

Why does lithium move on the surface of water during the reaction?

If someone asks me to number the most notable "textbook experiments" I would definitely name "the comparison of the reactions of alkali metals with water" among the most favorites. We just happened ...
2
votes
1answer
70 views

Concentration uncertainty

(All volumes were measured using a measuring cylinder which has a $\text{±0.5 cm}^3$uncertainty) You have a $\text{50 cm}^3$ of 0.5 M solution to begin with You then make a 0.4 M solution by mixing ...
4
votes
1answer
32 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, ...
10
votes
3answers
296 views

Does increasing concentration of copper sulphate decrease or increase its conductivity?

I am a high school student and for my chemistry lab, I did an electrolyis experiment on how the changing concentration of electrolyte (copper sulphate) will change the rate at which the copper is ...
2
votes
0answers
22 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 ...
3
votes
1answer
46 views

Titration of bases against HCl

Suppose I take three bases in a solution, $\ce{NaOH}$, $\ce{Na2CO3}$ and $\ce{NaHCO3}$, and I titrate this solution with $\ce{HCl}$. Since the strengths of the bases are different, does it mean that ...
2
votes
1answer
61 views

Can we do combustion caused by limited supply of air in a lab? How?

For example Ethyne in combustion by limited supply of air $$ \ce{ 2C2H2 + 3O2 ->[\Delta] 2CO2 + 2H2O + 2C } $$ vs. $$ \ce{ 2C2H2 + 5O2 -> 4CO2 + 2H2O + Energy } $$ What are the ...
1
vote
1answer
61 views

Find amount of Acid and Base required to make buffer

I am wondering if it is possible to know exact amount of acid and base that we can put in together to make a buffer. I want to make a 0.05M Extraction buffer using Disodium Hydrogen Phosphate and ...
-3
votes
1answer
64 views

Is it possible to separate aluminum hydroxide? [closed]

I want to know a way to separate aluminum hydroxide into aluminum and hydroxide ions, with a chemical reaction, or another process if necessary. I have $\ce{Al(OH)3}$ and I want to separate it into ...
1
vote
1answer
62 views

concentration of magnesium chloride solution in an experiment? [on hold]

I want to make a solution with 30% concentration of Magnesium Chloride and I need a total of $72~ \text{kg}$ of solution. the magnesium chloride is not pure, the composition of it is ...
2
votes
1answer
36 views

Alcohol spectrophotometry

A couple of weeks ago we did a lab where we had a bunch of standard solutions of alcohol, dichromate, and sulfuric acid. We also had one unknown concentration. We heated them so they would all react, ...
3
votes
1answer
241 views

Synthesis of 4-iodonitrobenzene

I was trying to synthesize 4-iodonitrobenzene in the lab today - however, the appearance of my product really confused me. At first, I added conc. sulphuric acid to water and 4-nitroaniline. This ...