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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What stable arrangements of hydrogen-bonded water exist in the range of 4-20 water molecules?

Water clusters made up of various numbers of water molecules have been described. Are all of these structures theoretical? What experimental evidence supports any of these structures? How does the ...
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1answer
36 views

Removing the hydrazine byproduct from the mitsunobu reaction

Looking to remove the hydrazine byproduct left after the mitsunobu reaction. Using DIAD and polymer bound triphenyl phosphine. The reduced diad is coeluting with my product on silica. My thoughts for ...
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0answers
43 views

How to crystallize out reaction mixture from DMF?

Reaction was carried out in DMF, and TLC shows that the reaction has completed. But how to separate reaction mixture i.e. product from DMF? Edit Steglich Esterification was carried out and the ...
4
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1answer
67 views

Is there a means to measure pH without indicators?

I have created a solution that should contain hydroxide ions. Therefore, the pH > 7, but is there any way to roughly estimate the pH in absence of any indicator? Maybe using current, or checking ...
2
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2answers
571 views

What salts (or other substances) are available for increasing water's boiling point?

Increasing the boiling point of water by adding salts or other compounds would be very useful when working with a water bath while refluxing, because with pure water you cannot reach temperatures over ...
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0answers
20 views

What kind of suspension liquid should be used with bulk ferrofluid (so it does not stain the glass) [duplicate]

I am an Engineering student and I'm currently on a project meant to demonstrate some properties of magnetic fields. I want to put my bulk ferrofluid in a glass bottle with a suspension solution (A ...
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2answers
15 views

Chemical reactions in SFE?

What are the chemical reactions and/or chemical processes that take place during SFE(supercritical fluid extraction)? Namely supercritical $\ce{CO2}$.
3
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2answers
54 views

Why pipetting with a 30° angle?

After seeing https://www.youtube.com/watch?v=qorl6rKLmRs, I was left to wonder why use a 30° angle between the flask and the pipette when emptying it. I can imagine it is important to touch the flask ...
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1answer
55 views

Help with simple DIY procedure to measure diffusion?

While I am not asking the question here, a recent question concerning osmosis at the Bio SE caught my interest. In a nutshell that question was, given isotonic solutions of sugar inside and outside an ...
2
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1answer
47 views

Recrystallization of two unknown compounds?

I managed to separate a binary mixture(in solid form) of two unknown substances into two individual solid compounds. For the separation, I used an acid-base extraction with dichloromethane, NaOH, and ...
3
votes
2answers
48 views

Water flow in condenser

How should the water flow in your condenser? From the flask to the top of the condenser, or from the top of the condenser back to the flask? I could imagine both: flask to top will fill the entire ...
5
votes
1answer
74 views

Rusting of an Iron nail at oil water boundary surface

Recently at school, I did some experiments on corrosion. Everything mostly went as expected, but the result in one of the test was quite baffling. This test had an iron nail in water with some of ...
2
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0answers
12 views

Synthesizing monodisperse PbS quantum dots

For a research project, I am trying to synthesize lead (II) sulfide quantum dots using the method of Li et al.. Basically, I am injecting sulfur dissolved in 1-octadecene into a mixture of PbO, oleic ...
3
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2answers
38 views

Refluxing with tilted condenser

Can you reflux without any problems/dangers with a tilted condenser (e.g. because you don't have enough space in your fumehood)? I would say there isn't a problem, because both the surface area of the ...
1
vote
1answer
62 views

Separation of Binary mixture?

I will be given a binary mixture containing two unknown compounds(the mixture could be either liquid or solid- I don't know yet). The plan of the experiment is to identify the two compounds. So my ...
0
votes
1answer
30 views

How do you perforate a teflon sheet?

I have a sheet of thin unperforated teflon that I need to perforate by tomorrow for a lab I work in. None of my coworkers know how to perforate the sheet. Does anyone know how I can do this using ...
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0answers
41 views

Reactivity of thiosemicarbazide

How to form Schiff's Base at both the ends of the thiosemicarbazide? $\ce{NH2}$ of hydrazine part reacts easily to form Schiff's base i.e. imine. But $\ce{NH2}$ attached to $\ce{C=S}$ does not. How ...
2
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2answers
61 views

Calculating Avogadro's Number

For a school project, I am in a group tasked with calculating Avogadro's Number in multiple manners. Other than the Millikan Oil Drop Experiment, we know of no ways to compute it. A Google search ...
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0answers
11 views

Silica, Alumina and Sodium Hydroxide from Caustic Soda solution [on hold]

I had a solution containing Silica and Alumina in caustic soda. I need to extract the same from the solution separating Silica, Alumina and sodium hydroxide. How can I do it? Please provide the ...
4
votes
1answer
102 views

Synthesizing Aspirin Question

Take as example this http://njcmr.njit.edu/distils/lab/aspirins/nap4.html or even better this http://wwwchem.csustan.edu/consumer/aspirincons/aspirincons.htm Wash the crystals with 2-3 ml of ...
2
votes
1answer
63 views

Identification of zinc/aluminium/magnesium with copper sulphate solution

We are doing an experiment and would like to be able to identify zinc/aluminium/ magnesium . Would a copper sulphate solution work ? I hear that it turns black on contact with zinc, stays clear on ...
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0answers
27 views

Why are multiple extractions better than a single extraction? [duplicate]

I'm extracting $\ce{N-(4-butoxyphenol)-N'-(4-dimethylaminophenyl)thiourea}$ from thiombutosine (anti-leprosy drug) tablets. I'm doing this extraction with hot ethanol. My question is why are 4 ...
4
votes
2answers
90 views

Why is a volumetric flask shaped the way it is?

A volumetric flask does not look like an Erlenmeyer flask, but has more of a pear shape. Is it just to distinguish more easily between them while they are on the shelf?
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2answers
63 views

Preparation of phenylamine/aniline

This is the procedure I carried out in class: Reduction of nitrobenzene by using tin and $HCl$ acid After the completion of the reaction, $NaOH$ added to neutralize excess acid and dissolve any ...
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2answers
49 views

Different techniques of distillations

I know that fractional distillation is used to separate two liquids that are miscible in one another and have close boiling points. However, I am really confused about vacuum and steam distillation - ...
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2answers
48 views

What is the process involved in performing a mass spectrometry experiment?

I have heard that mass spectrometry is very time consuming: why is this? What is the process involved in performing a mass spectrometry experiment? What steps are the most time consuming?
2
votes
1answer
60 views

What is the difference between the reactivity of Lead subacetate and Lead II acetate undergoing a hydrothermal process?

I am attempting to adapt a hydrothermal method for synthesizing $\ce{PbS}$ nanocrystals to my school that contains a mixture of cationic and anionic surfactants sodium dodecyl sulfate (.05 mmol, SDS) ...
0
votes
1answer
52 views

Explain isotopic uranium/perchloric acid digestion [on hold]

What is happening in this video? Can you explain this technically as well as in layman's terms? I'll summarize it. I see a technician moving fuming mixtures of presumably uranium and organic ...
1
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0answers
21 views

To model early fluid flow which types of pumps should be used?

I have I microchannel test rig , I want to push a 150-300 ml/hr from water in my test , I would like to know which pump type i can use ?
4
votes
1answer
179 views

Why is filter paper fluorescent?

Typical filter paper used in chemistry lab (e.g. Whatman #1) exhibits autofluorescence in near UV with excitation maximum at 365 nm and emission maximum at 440 nm. It was reported in literature1 that ...
7
votes
2answers
144 views

Questions about Buffer System (Lab)

I will be doing a lab on Hydrogen Phosphate buffer system tomorrow and I have a few questions about the buffer system. I am not sure if my assumptions are correct. (1) What would happen to the rate ...
-1
votes
1answer
53 views

Compare Catalysts in Calorimetry Reaction [on hold]

I am writing a lab report and need some help understanding something. I have performed a calorimeter experiment and compared the different reactions that were taking place inside it with a ...
5
votes
1answer
65 views

Steam distillation- how it actually works?

To obtain phenylamine after it is formed from the reduction of nitrobenzene with tin, we carried out steam distillation. This is what I learned in class: "During the process,steam is injected ...
2
votes
1answer
163 views

Why can we not use water instead of blank control solution in enzyme catalysis with Peroxidase experiment?

I have to do a lab about enzyme catalysis with Peroxidase in my Chemistry class. We are to use the blank control solution in the experiment. My question is, why can we not use water instead? I did ...
4
votes
2answers
39 views

What's Standardization, and why do it?

Surprisingly, there are very few resources online (outside of obscure lab pages) that explain exactly what standardization is (not even Wikipedia!). The context is the phrase standardize the titrant ...
1
vote
1answer
21 views

How do you measure the chemical composition of stuff? [closed]

I'm not a scientist of any sort, I'm just curious. Here are some specific examples. Let's say I collect some rainwater and I want to find out what is in it that isn't water. How would you do that? ...
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votes
1answer
77 views

How alkanes can be prepared by aldehydes and ketones? [closed]

Preparation of alkanes by aldehydes and ketones, its chemical reaction and mechanism.
5
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2answers
84 views

Getting to use the lab!

Today I finally mustered the courage to go and talk to the director of the labs to politely ask him if I could use the labs out of class hours. Long story short, our lab sessions "are bad" because we ...
0
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2answers
47 views

Using Spectrophotometer to analyse enzyme reaction

Suppose we have two enzymes with concentration of 1X and 0.1X We then add a substrate and incubate the mixture for 1 or 10 or 20 minutes.( So,there will be total of six samples.) Question ...
5
votes
3answers
78 views

How do I create a concentrated solution of singlet oxygen (in the dark)?

Without appealing to reactions that require photons / light, how do chemists achieve a very high concentration of continually produced, though quite short lived, singlet oxygen in aqueous solution ...
4
votes
2answers
78 views

What is an effective experiment to demonstrate the safety of wearing leather shoes while experimenting in the chemistry lab?

Quite often (from my own experience anyway), one of the safety rules in a school (high school or university) laboratory is that the students must wear leather shoes. I like to demonstrate some of ...
0
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2answers
144 views

What does “EM grade” mean

I'm looking at purchase orders and I see purchases for chemicals like the following. Glutaraldehyde, EM Grade, 25% What does the "EM Grade" mean in this text? It says that it's recommended for ...
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3answers
111 views

Alternatives to Ring Stands

I'm trying to find an alternative to simple ring stands to hold a simple electrochemical cell. The issue is that it is difficult to adjust the height to the right position to within even a couple ...
0
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0answers
270 views

How to calculate lattice parameter only using planes and d spacing

I am trying to find lattice parameter of a hexagonal crystal, usually I use cellcalc for calculating lattice parameter of a crystal structure. In that software it asks only two queries, one is details ...
4
votes
0answers
24 views

How to get defect-energy level diagram from PL data

I am reading this article Phys. Chem. Chem. Phys. , 2011, 13, 14902-14905 and seen that the authors have drawn a image of defect level using PL data Can you explain me how this diagram can be drawn ...
2
votes
1answer
107 views

Belousov-Zhabotinsky reaction

The Belousov-Zhabotinsky reaction is a very fascinating one. The Chemistry behind the reaction concerns thermodynamics and equilibrium. I want to perform the experiment, but I'm not able to find ...
7
votes
2answers
6k views

Chemistry behind Gale's Coffee Maker in Breaking Bad

Is there a scientific basis for the coffee making equipment which Gale describes in Breaking Bad? He talks about maintaining the right conditions for bringing out the coffee flavor without degrading ...
3
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0answers
597 views

Why are NaCl and NaBr not soluble, whereas NaI is soluble in acetone (in the Finkelstein reaction)?

My book says: Finkelstein reaction is particularly useful for preparing iodoalkanes. The iodoalkanes are obtained by heating chloro or bromoalkanes with a concentrated solution of sodium iodide ...
2
votes
1answer
64 views

Changes in defects in a material due to heat treatment

Currently i am doing some research on optical properties of a oxide material and for that purpose i have done some photoluminescence study on it. Because this is an ongoing research i cant divulge ...
2
votes
1answer
47 views

Uncertainty propagation question?

Question related to uncertainty propagation. I was taught that when adding/subtracting measurements, add the absolute uncertainties, and when multiplying/dividing measurements, add the relative ...