Questions tagged [experimental-chemistry]

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 field of research.

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159 views

Determining the chemical formula of a polyiodide Salt

I've got a compound with formula $\ce{N(CH3)4.I(I2)_x}$. By mass I've got $\pu{0.138 g}$ of $\ce{I2}$ present out of $\pu{0.189 g}$ of polyiodide added. How do I find $x$? This is the exact part of ...
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1answer
137 views

What is the smoke from KNO3 with sugar reaction?

So I was doing a reaction between $\pu{0.02mol}$ $\ce{KNO3}$ and $\pu{0.01mol}$ $\ce{C6H12O6}$ and there was a smoke. What is the chemical reaction, and what is the smoke?
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1answer
125 views

Different HCl concentrations and iron nails [closed]

Hey guys I am at high school and we have a project on designing our own lab. My questions is will different concentrations such as 10%, 20%, 30% and 37% have an affect on the corrosion of an iron ...
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0answers
96 views

White compound, insoluble in water, turns pink and then white again on adding water

Which white, ionic compound(s) that is insoluble in water turns pink when you add only a little of water but white again when you add more water? I know that the cation is one of the following: $$\...
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0answers
21 views

The Salt Effect stops working in extreme cases?

I and three friends did an experiment where we investigate the salt effect, also known as the uncommon ion effect. The specifics are that we made a $\pu{1L}$ solution saturated with $\ce{CaCO3}$ and $...
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0answers
18 views

What should I do to prevent cellulose from turning black? [closed]

In my research on producing ethanol from grass, I have boiled 4g of grass in a beaker on a Bunsen burner with 30ml of sulfuric acid (bottle of 1 mol/l). However, within a few minutes the solution ...
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1answer
84 views

How to synthesize tetrabutyl titanate from titanium dioxide powder?

How do you synthesize tetrabutyl titanate $(\ce{[CH3(CH2)3O]4Ti})$ from titanium dioxide ($\ce{TiO2}$) powder? As I know, we can get $\ce{TiO2}$ from tetrabutyl titanate, but how can we do the ...
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3answers
128 views

How to tell the difference between octane-1-ol and oct-1-ene?

How to tell the difference between octane-1-ol and oct-1-ene? The things I can do are: check their solubility in water use bromine water use $\ce{KMnO4}$ use sulfuric acid I assumed that checking ...
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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 ...
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0answers
262 views

What result should I have obtained in these tests? Also, what went wrong? [closed]

As part of a Chemistry practical, I had to five different tests for things, and note down the result. Unfortunately, at least several results were incorrect, and despite hours of research, I cannot ...
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0answers
782 views

Conversion of a permeability value from barrer to SI unit

I have done a permeability experiment on LDPE in the presence of air. At $\pu{30^\circ C}$, the permeability was found to be 1.846 barrer. Now I am trying to apply this permeability value to a ...
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1answer
358 views

Anodisation of aluminium in sulfuric acid - Electrolysis reactions [closed]

As an experiment for electrolysis and to show how a metal can be protected of corrosion, I am trying to anodize an aluminium plate, using sulfuric acid as electrolyte. I know the aluminium plate is ...
3
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1answer
317 views

Isopropyl alcohol still leaves evaporation residue after distillation

I just finished distilling two liters of IPA because evaporating 5 ml on a watch glass revealed it to contain quite a bit of dissolved impurities. However, it still leaves some residue, even though I ...
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0answers
194 views

What is causing a blue colour when sodium bicarbonate, vinegar and aluminium are reacted together? [closed]

My 10 year old has been experimenting in my kitchen! The other day he wanted to know why when he reacted bicarb soda and boiling vinegar in a container with some aluminium foil, the solution turned ...
3
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1answer
75 views

Experimental measurment of thiosulphuric acid decomposition kinetics

Problem I am trying to do a kinetics analysis on the following reaction: $$\ce{Na2S2O3 {(aq)} + 2 HCl {(aq)} -> S {(s)} + 2 NaCl {(aq)} + SO2 {(g)} + H2O {(l)}}$$ Suggested Method However, most ...
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1answer
83 views

When to disconnect tubing in vacuum filtration?

The UCLA site says in step 6 to disconnect the vacuum tubing before turning off the vacuum and the second link from Leeds says in step 11 to turn off the vacuum source first and then disconnect the ...
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1answer
70 views

Is the formula λ = h/mc wrong?

When we derive De Broglie's equation, we can do that from two ways. That's, 1st step:- $E^2=p^2c^2+m_0^2c^4$ For a Photon $m_0=0$, So, we have , $E^2= p^2c^2$,i.e. $E=pc$ -----(1) $E=hc/λ$----(2) ...
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1answer
1k views

Why does Hydrogen Peroxide decompose? [duplicate]

I understand that Hydrogen Peroxide decomposes into oxygen and water over time. But why exactly does it do this? Could someone give me an explanation down to the molecular level as to why and how this ...
2
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0answers
68 views

Results of mixing HSbF6 and O2F2

I'm an amateur writer and one of the topics I deal with is what happens when a slightly-mad scientist and engineer is given an opportunity to work with full-on “magic.” So there are situations where ...
6
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2answers
570 views

Producing sulphur dioxide for using in a reaction

I am doing an investigatory project on studying the coloured reactions of d-block and f-block elements. I have included two reactions that require sulphur dioxide as a part of my study. $$\ce{5SO2 ...
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1answer
1k views

How would you separate sodium chloride and copper sulfate?

I've tried dissolving both compounds in water and evaporating the mixture, but this leaves a combination of brown and green crystals. Is there was any way to cleanly separate both compounds? Any ...
6
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1answer
217 views

Can gas be made to block radiation better?

Can any gas block radiation? I ask this because I would like to know if the properties of any gas element would chemically react differently with radiation from adding an electrical current. This ...
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1answer
713 views

Determining the depression in freezing point experimentally

I was reading about Beckmann's method for determining the depression in freezing point: First, the solvent is placed inside the cooling chamber directly and the approximate freezing point is ...
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1answer
57 views

What effect, if any, would each of the following actions have on the calculated concentration of the NaOH in this experiment? [closed]

What effect, if any, would each of the following actions have on the calculated concentration of the NaOH in this experiment? (e.g. would the calculated concentration be higher, lower or the same?) ...
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1answer
281 views

Hydroxyl group to free amine in polyethylene glycol using CDI?

For converting $\ce{OH}$ of methylated polyethylene glycol. The first step is converting hydroxyl group to imidazole carbamate as an active intermediate. But what about the next step? If I will add ...
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1answer
85 views

Can heat capacity at constant volume for a gas decrease as temperature increases? [closed]

I found a function for the $C_V$ of a gas which is being heated under constant volume,but the function shows that the $C_V$ is decreasing. I was wondering if this is possible for any gas since I know ...
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0answers
96 views

What are the optimal conditions for the complete acid hydrolysis (using HCl) of potato starch? [closed]

I'm hoping someone can provide the specifics on the optimal conditions required for the complete acid hydrolysis (using $\ce{HCl}$) of potato starch? I will be using an autoclave (~$\pu{15 psi}$ @ $\...
4
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1answer
50 views

Why are DOM lithiations sometimes conducted at −78 °C and othertimes conducted at elevated temperatures?

I'm looking specifically at n-butyllithium. I've noticed a number of lithiation reactions are conducted at −78 °C, whereas I've encountered papers conducting these reactions at elevated temperatures, ...
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0answers
33 views

Color change of nitroglycerin. Potential hazard?

I recently nitrated around (~7mL) of glycerol through a process I have performed many times before. The nitroglycerin has been stored for ~3 weeks, and I noticed a drastic change in color from clear ...
2
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2answers
8k views

Mixing hydrochloric acid and sulphuric acid, both concentrated

In the chemistry lab, I stupidly decided to mix hydrochloric acid and sulphuric acid, both concentrated, in a random ratio, which was about $\pu{50 ml}$. When I poured them in one test tube, the ...
4
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0answers
106 views

What is a good solvent for pentacene?

I am doing an experiment with pentacene molecule ($\ce{C22H14}$). I want to clean my sample reservoir after using it. But I show in some literature that it is slightly soluble in organic solvent. ...
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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 ...
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0answers
86 views

What's a good chemistry book for a practical man [closed]

Yesterday I picked up my old organic chemistry book and started to read it from the first chapter. After a couple of minutes I realized that I don't understand the concepts at all. The first chapter ...
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2answers
7k views

Hottest region of Bunsen flame

Since region 1 is closer to the source, I presume it to be the hottest as complete combustion takes place there. Also, this is the part where the gas mixture(responsible for flame) reacts with oxygen ...
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2answers
4k views

What is the purpose of a boiling stick when heating a reaction mixture?

What is the purpose of a boiling stick when heating a reaction mixture? I read some stuff online and still don't understand how it works. Does it just ensure that the mixture will boil evenly? If so, ...
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0answers
43 views

Can the solutions for the Briggs Rauscher experiment be made ahead of time and stored?

I will be performing the Briggs Rauscher Oscillating reaction as a part of an investigation into the effect of heat on the antioxidants. This will require 3 solutions to be mixed together, as shown ...
3
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2answers
5k views

How can bromine water be used to distinguish between benzoic acid and salicylic acid?

I have come to learn that bromine water can distinguish benzoic acid from salicylic acid. I know that salicylic acid on reaction with bromine water forms 2,4,6-tribromophenol. I think that benzoic ...
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1answer
262 views

Is it possible to predict the color of the flame test result based on the element's structure?

The flame test is quite simple to do and very useful on the chemistry world, but to understand what your results mean you need to know previously a range variety of element-color relations. So, since ...
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0answers
50 views

If we are supplying energy continuously, why will the electrons jump down to the lower state? [closed]

We know in a flame test an electron goes into excited state. When it jumps down to a lower energy state, we can see the color of the flame if it's in our visible region. My question: we are supplying ...
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1answer
46 views

Why is aluminium used to treat waste after a lab experiment? [closed]

How does adding aluminum metal pieces into a waste beaker help treat solids and liquids in the beaker so you can safely send the solids to a landfill and dispose of the liquids in the sink drain ...
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1answer
3k views

Why does iodine solution turn transparent on adding base? [closed]

Yesterday in biochemistry lab when I added sodium hydroxide to iodine solution. The iodine turned transparent. Can someone please explain why is this happening?
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1answer
82 views

Transesterification of vegetable oils to produce biofuels - problems in the lab

I'm an undergraduate doing a small research project on biofuels. I have 12 hours of lab time to investigate something about biofuels. I've chosen to explore how the fatty acid content of different ...
2
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0answers
140 views

Does specific heat capacity of the container have an effect on the exactitude of a calorimetre?

I'm doing a lab on what is the best material for a calorimetre. I chose glass, aluminum, styrofoam cup, paper/cardboard cup and a plastic cup. I've found that the cardboard cup was the best followed ...
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0answers
34 views

Readings about chiral resolutions at the undergraduate level

Does anyone know of a resource which clearly explains the scientific theory and experimental methods involved in chiral resolutions? I have access to the American Chemical Society, Tetrahedron, ...
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0answers
34 views

Why does the sodium become transparent after burning?

I know that if we throw a piece of sodium into water then it will melt first then it will explode. But under different conditions, the above situation will not happen. If we keep a piece of sodium on ...
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0answers
42 views

Why is this scintillator component turning into a milky-white emulsion?

I am a chemistry and physics double major doing some chemistry work in a nuclear physics lab. My mentor is a physicist, so his area of expertise is occasionally mismatched with what I need for my ...
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0answers
101 views

Non-ideal velocity distribution of gases

A recent question about the velocity distribution of ideal gas molecules got me wondering. How much would the velocity distribution vary for non-ideal gases? I was wondering about a mixture of ...
4
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1answer
1k views

Sodium and potassium produce a strange liquid, why the liquid explode when it gets contact with water? [duplicate]

I saw an experiment sodium and potassium mixed together to produce a liquid alloy but when the liquid get contact with water then some kind of explosion occur. Why the explosion occur when the ...
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2answers
466 views

Diffusion rate of gases

What is the effect of temperature on diffusion rate of gases? Do the diffusion rates of gases decrease with an increase in temperature? Why? I just read it somewhere that the diffusion rate of gases ...
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1answer
438 views

Is it advisable to make vinegar at home using acetic acid?

I've taken only a couple university chemistry courses. In the lab, when we always used acetic acid in powdered form, it struck me how when buying vinegar in a bottle from the store, you must be paying ...