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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.

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.
Among others, this includes, but is not limited ...

1760 questions
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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 first(as soon as valve is open). So, the…
MollyCooL
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Is argon preferred over nitrogen for maintaining an inert atmosphere?

I recently started a project in a new lab-group over Summer that does medicinal chemistry. Unlike in the undergraduate labs, they use argon instead of nitrogen for their inert atmosphere work. When I asked around, the lab members said that it was…
James Dealon
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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, then what's wrong when a reaction doesn't boil…
JeeJee
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Can atomic partial charges be measured in molecules experimentally?

Can we measure atomic partial charges in molecules experimentally? The charge of isolated ions can be measured, but when atoms are part of a molecule, the case is much more difficult. We do not really know where one atom starts and where another one…
Yoda
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Why do research papers mention experimental details in such detail?

The paper Analysis of cyclic pyrolysis products formed from amino acid monomer has the following to say in it's experimental section: Glycine, phenylalanine, tyrosine, tryptophan, serine, and valine were purchased from Daejung Chemicals & Metals…
Aniruddha Deb
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10
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Products of Lead(II) nitrate decomposition

It is known, that decomposition of Lead(II) nitrate is one of the ways of generating $\ce{NO2}$ for lab use. I recently did this in order to acquire $\ce{NO2}$ in liquid form (ambient temperature was ~0 °C), and got quite strange results. First,…
BarsMonster
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Why pipetting with a 30° angle?

After seeing this youtube video, I was left to wonder why to use a $30^\circ$ angle between the flask and the pipette when emptying it. I can imagine it is important to touch the flask with your pipette when emptying, because the liquid prefers…
Jori
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What is a baseline?

I am currently doing a lab write up for biology, in which the purpose of the lab is to "Develop a Method for Measuring Peroxidase in Plant Material, and to Determine a Baseline." This is supposed to be accomplished by finding the relationship…
Keychain1
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What would be the effect of adding liquid beyond the calibration mark on a volumetric flask?

If this happens in the course of preparing a volumetric solution, what should be done?
Eunice
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Why do people consider caffeine ineffective after its half-life?

Assuming you take $\pu{200mg}$ of caffeine, it's half life is roughly 6 hours. So after 6 hours there should still be $\pu{100mg}$ of caffeine in your body. Then why is it generally said that after six hours caffeine's effect should wear off?…
Ilan Kleiman
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Linear PEI Solution Making

I'm making a solution with linear poly(ethyleneimine) $\ce{[CH2CH2NH]_{n}}$. The bottle indicates that the substance is hygroscopic and must be dealt with under inert gas. Is this really necessary? I don't currently have access to such a space -…
Danielle
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Have Ionic Liquids been used to refine aluminum on an industrial scale?

Ionic liquids have been shown capable of reducing aluminum trichloride to solid aluminum at 3kw-hrs per kg of Al(s) produced instead of the current ~15kw-hr/kg. However, this would seem to neglect the fact that bauxite is aluminum trioxide not…
Dale
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How do we identify the molecular formula from the empirical formula of a completely unknown substance?

Suppose you are given a sample of new (undiscovered) hydrocarbon with 600/7% $\ce{C}$ and 100/7% $\ce{H}$. (From combustion or any other method) We can find the empirical formula to be CH. Then how the we figure out whether it will be $\ce{C2H2}$ or…
darkspine
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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 are given a protocol, and like babies we just…
OFRBG
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Can you literally separate air from soil?

My teacher poured water over some soil and said that the air bubbles prove that soil contains air. However I was wondering if there is a more direct approach to proving that soil contains air, like explicitly separating one from the other. Is there…
Raghib
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