Questions related to the methodologies, equipment requirements and safety considerations of any experimental procedure.

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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 ?
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1answer
48 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 ...
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1answer
18 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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2answers
39 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 ...
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2answers
66 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 ...
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0answers
183 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 uses cellcalc for calculating lattice parameter of a crystal struture. In that software it asks only two queries one is details ...
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0answers
15 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 ...
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1answer
47 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 ...
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1answer
42 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 ...
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0answers
206 views

Calculation of Atomic weight percentage in AAS

I am currently doing doping studies in a system similar to this ($A_{x}B_{1-x}$) and i have to find atomic weight percentage of $B$ element using atomic absorption spectroscopy(AAS). I have prepared ...
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1answer
409 views

How can I determine the boiling point of a compound using simple distillation?

I've graphed a distillation curve (temperature against volume of distillate) from the data obtained from a simple distillation experiment. The substance can be any of methanol, ethanol, 1-propanol or ...
2
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1answer
93 views

How to quickly cool a test tube without cracking it?

Is there a way to safely cool a heated test tube quickly without cracking it due to sudden thermal stress in the glass? One thing that I tried was blowing on it, cooling it in slightly lukewarm water ...
2
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1answer
75 views

How to properly work with potassium HMDS

What is the proper procedure for working with KHMDS? I would like to use it to deprotonate a compound and have a bottle of KHMDS in toluene. Does it need to be handled under inert atmosphere? And ...
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1answer
33 views

Less maintenance-dependent continuous pH testing

I am creating an automated chemical component mixing system (DIY project). One of the features required is continuous monitoring of pH value in my main solution. I do not need it to be very precise, ...
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1answer
168 views

Is it safe to condense water into a liquid nitrogen trap?

I'm trying to remove water from an imidazolium salt (i.e. dry the salt). However I want to know if it is safe to remove the water under vacuum. Is it safe to condense water into a liquid nitrogen ...
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2answers
484 views

What is the procedure of designing a salt bridge for a galvanic cell?

I'm doing an experiment where I'm measuring the effect of changing the $\ce{Cu^{2+}}$ ion concentration on the voltage in a copper-zinc galvanic cell. I'll be doing at least five trials for each of ...
3
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1answer
305 views

How is the time for a test tube in a centrifuge determined?

I came across some hairy math that's used for analytical centrifugation, mostly for things like determining the sedimentation rate for liquids. However, what I don't understand is how someone ...
3
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1answer
87 views

What is a “lagged bath”?

First question, and this is one I've searched for in vain. In the context of setting up cooling baths, I've come across the term "lagged" bath. I cannot extract what this means from any available ...
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1answer
442 views

Why should I add lithium bromide to my GPC eluent?

I'm running gel permeation chromatography (GPC) of a polar, uncharged polymer (acrylamide-based) in a polar solvent (dimethylformamide). The literature recommends adding a salt to the eluent; for my ...
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1answer
40 views

How are crystals formed from a gas?

In crystallization, crystals are formed from liquids by cooling. How can crystals be formed from a gas by cooling?
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1answer
978 views

Inherent error in mass and volume?

In one of my chem classes I had to do a lab that involved finding the mass and volume of a substance. I did three trials and for my mass I got 9.3g, 9.3g, and 9.4 g. For my volume, I got 9.7ml, ...
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1answer
785 views

Pipetting strong acid with plastic material

Can I pipette concentrated sulfuric acid using a plastic pipette tip? Will either the plastic or the acid be affected?
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1answer
124 views

How would I neutralize a PEP (Phosphoenolpyruvic) acid?

PEP (Phosphoenolpyruvic acid) is acidic but I need to make it neutral. I need a solution (pH 6-8) of PEP in a final 1 mL volume with a concentration of 100 mM. How would I make this?
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1answer
505 views

How did Michael Faraday melt Sodium Chloride?

Michael Faraday melted sodium chloride in a silver spoon and ran an electric current through the molten salt, which released chlorine as a gas and left pure sodium behind. Sodium chloride melts at ...
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1answer
183 views

What is the correct name for this lab technique [crystallization]

Take a glass rod and rub vigorously the wall of the flask, the substance will crystallize out of the solution. Take a fire polished stirring rod and etch (scratch) the glass of your beaker. The small ...
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1answer
62 views

How do you determine the amount of acrylamide in foods such as baked fries?

There are many food studies which determine the concentration of a substance in a food item. For example, this study determines the concentration of acrylamide in solid foods like fries. By what ...
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1answer
175 views

How to translate the mobile phase from thin layer chromatography to column?

I recently was told that once you find a good solvent mixture for separation on thin layer chromatography (TLC), you should only use 10% of the more polar solvent (for silica) when you run your ...
3
votes
2answers
611 views

How long does it take to run a MS/MS experiment

I am not planning to do these types of experiments but I would like to know the order of magnitude of the time it takes to run an LC-MS/MS experiment. Let's assume that I have the sample prep ...
6
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3answers
333 views

Experimental calculation of solubility product constant

I mixed $6.0~\rm mL$ of $.01\:\rm M$ $\ce{Pb(NO3)2}$ and $6.0~\rm mL$ of $0.02\:\rm M$ $\ce{KI}$ and $8.0~\rm mL$ of water and a precipitate (barely) formed. I calculated the $K_{sp}$ with ...
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2answers
283 views

What can I do if I don't get a phase separation between my organic and water phases?

Solvent extraction in a separation funnel is a very common method in preparative organic chemistry. But sometimes you don't get a nice phase separation between the organic and the water phase. What ...