The experimental-technique tag has no wiki summary.
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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 ...
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65 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 ...
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40 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
133 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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31 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
298 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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329 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
94 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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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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0answers
118 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 ...
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1answer
56 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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117 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 ...
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279 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 ...
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161 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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179 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 ...
