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0
votes
2answers
273 views

Crystallization from a solution

I was wondering if there is any other way to crystallize materials from a solution other than using supersaturation? Thanks,
3
votes
1answer
821 views

Parts of a manometer

There is a poor quality photo in the diagram of a manometer below: The picture is too poor for me to understand what they mean by "glass pointer marks calibrated volume". I would be interested if ...
5
votes
1answer
4k views

What is the substance in the new water cooler filter that give bubbles and taste a bit like soap

Recently the water cooler was replace with a new filter. However, when I refill my water kettle with the water from the water cooler, there are many bubbles and the taste was a bit like soap. What ...
3
votes
1answer
1k views

Forms of Henry's law versus ideal gas law

This might be a slightly daft question as I'm a physicist rather than a chemist, but I have a slight problem in using Henry's law which I think I can circumvent using the ideal gas law – I'd be ...
0
votes
2answers
8k views

How does the volume of a mole of ideal gas relate to pressure and temperature?

The volume of a mole of gas is: $\ce{22.4 l}$ directly proportional to pressure and Kelvin temperature. directly proportional to pressure, inversely proportional to Kelvin temperature. inversely ...
-3
votes
1answer
718 views

Why can't you see air but can feel it [closed]

Is there a device that can measure the air in the room in lbs? I would appreciate the anseer
8
votes
4answers
25k views

Why won't water freeze if you put ice in it, despite ice being frozen?

Just now I got some room temperature water and added some ice to cool it, and it just came to me, like the scientist I wish I was ... why doesn't frozen (freezing point) ice added to higher ...
5
votes
3answers
270 views

Can I perform a stable isotope analysis at home?

I'm interested in measuring the stable isotope ratios of some bird feathers. I'm aware that a mass spectrometer is required to measure stable isotope ratios. Is it possible to measure stable isotope ...
6
votes
3answers
14k views

Are there substances that cannot undergo combustion?

Are there substances that cannot undergo combustion? If so, what are they?
5
votes
1answer
3k views

How do you calculate the absorption spectrum of water?

If you look online you can find various graphs of the absorption spectrum of water. The graph below for examples comes from this blog post. As far as I can tell these graphs come from empirical ...
3
votes
3answers
12k views

Oxidation State in Tetraaquadichlorochromium(III) chloride

$\ce{[Cr(H2O)4Cl2]Cl}$, Tetraaquadichlorochromium(III) chloride According to a book, the (III) indicates the oxidation state of chromium, but it doesn't explain why. Cr has 6 valence electrons. How ...
2
votes
2answers
7k views

How many valence electrons does the azide ion have?

We had a test and and we had a question asking the number of valence electrons in an azide ion, $\ce{N3^{-}}$. I find out that the answer is 16 but I could not understand how. I saw the structure. ...
0
votes
1answer
14k views

Why is methyl group more electron-donating than tert-butyl group?

As title says, why is methyl group more electron-donating than tert-butyl group? The context behind this is stabilization of conjugate base. (http://www.khanacademy.org/science/organic-chemistry/...
12
votes
3answers
38k views

Why do molecules having a higher relative molecular mass have stronger inter-molecular forces?

Why do molecules like alkanes with higher relative molecular mass ($M_\mathrm r$) have stronger intermolecular forces? For example, methane ($\ce{CH4}$) has a weaker intermolecular force than pentane (...
0
votes
1answer
54 views

What does $\mathrm{A}_r(\mathrm{H})$ represent when calculating the average natural weight of an elemental atom?

I have a question that explains the weights and abundances of various hydrogen isotopes, and the question concludes by asking to: Calculate the atomic mass of hydrogen $\mathrm{A}_r(\mathrm{H})$ (...
3
votes
2answers
962 views

Do chemical compounds have spectral lines, or only elements?

I know that elements (ex. Ag) have spectral/emission/absorption lines, but do chemical compounds (ex. NaCl) have spectral lines as well? Ones that when seen you can tell that that compound (NaCl) is ...
2
votes
1answer
6k views

Assay over 100% (L-Cysteine Hydrochloride Monohydrate)

In reading a COA (Certificate of Analysis), I came across an Assay line: The Assay is 100.5% where "Lower Limit" is 98.5 and "Upper Limit" is 101.0 This product ...
4
votes
2answers
3k views

Is there a word for a compound that has both ionic and covalent bonds?

For example, calcium carbide (CaC$_2$) has covalent C‒C bonds and ionic Ca$^{2+}$‒ C$_2^{2-}$ bonds.
13
votes
3answers
10k views

Can you heat water with additives?

I have been curious about this question for a while. If you want to warm up a large amount of water, is it feasible to do this by adding a substance that has an exothermic reaction with the water? ...
7
votes
4answers
77k views

How do I chill water without a refrigerator?

How can we chill water in a plastic bottle without a freezer or refrigerator? Scenario: I'm in the office and I have two plastic bottles of water (brought from home). I'm in the office for 3 to 4 ...
5
votes
1answer
2k views

Can dust or fingerprints interfere in ultra-violet spectroscopy

My question pertains generally to any form of spectroscopy, but I'll focus on UV spectroscopy. I am trying to get information on carrying out spectroscopy, but most of it is theoretical. Wikipedia is ...
0
votes
2answers
223 views

How does pressure shift equlibrium

Here is a question from my practice problems: I know that the answer is A, but I don't know why. Is it because A has the most moles of gas on the left? thanks
2
votes
1answer
332 views

Air recycling system(CO₂-->O₂) or (CO₂-->fuel)?

I'm not a chemist but I'm working on an eco-friendly project that is supposed to recycle $\ce{CO2}$ from the air and convert it to $\ce{O2}$ or at least a usable fuel source ,the system can use the ...
2
votes
1answer
2k views

Acids that donate just one proton

What is the general name for acids that can only lose one hydrogen ion? (i.e. $\ce{HCl}$) What is the general name for acids that can lose $n$ hydrogen ions? (i.e. $\ce{H_3PO_4}$, which can lose 3) ...
1
vote
1answer
230 views

How many protons are required to satisfy hydroxyamine's (NH₂OH) lust for protons?

I ask because I'm trying to write an equilibrium equation for this reaction and I'm wondering whether an extra 2 protons will be required after one is taken to attack the $\ce{OH}$ group and turn it ...
1
vote
1answer
6k views

Liquid with low specific heat and high thermal conductivity (relative to water)?

As the title suggests – does there exist a liquid with a lower specific heat then water but with a higher thermal conductivity? I thought of this in the context of sous vide cooking: Ideally, the ...
5
votes
2answers
3k views

Flame temperature for cooking food

Which has hotter temperature, blue flame or yellow flame?
4
votes
1answer
1k views

Why is Lanthanum a "fluoride ion sensitive electrode" and hence used for measuring "flouride concentration"?

My chemistry text book says that "Atomic Absorption Spectrometry (AAS) can be used to determine the concentration of metal ions, but other methods must be used for anions. One convenient method is to ...
2
votes
2answers
203 views

Helium empirical wavefunctions

I know that analytic forms of the Helium wavefunctions are not known. However, are there empirical expressions for the low-lying states of Helium? I'd like to use them to calculate some transition ...
4
votes
3answers
39k views

Valence electrons in helium?

I am having trouble understanding how valence electrons are counted in Helium. My references are: Here where it appears that Helium has 0 valence electrons because the shells are finished Here ...
0
votes
1answer
148 views

Transition Metals' Charges

I came across a compound $\ce{[FeO4]^{2-}}$ but $\ce{Fe}$ has +6 charge according to my calculations. How this is possible ? Or it is possible but my periodic table is kind of non-detailed one. (On ...
17
votes
2answers
20k views

Why is a theoretical titration curve higher than a practical one?

I'm currently in high school and I did two titrations. The first one is a titration of $10.0~\mathrm{mL}$ $0.1~\mathrm{M}$ $\ce{HCl}$ with $x~\mathrm{mL}$ $\ce{NaOH}$. I obtained the following ...
8
votes
1answer
254 views

How do chemists decide on which detergent to use?

I found betaine in my face wash. I think it is there because it has a hydrophobic (non-polar) end that can pick up grease, and a hydrophilic (polar) end that means it is attracted to polar solvents, ...
2
votes
1answer
23k views

The influence of lemon juice & sugar on the ph-value

If I add equal amounts of lemon juice and sugar into water, does the ph-value remain unchanged, as both cancel each other out? This question arose in my head as I learned that pouring milk into ...
1
vote
1answer
760 views

Geometrical Isomerism of Metal Complex

Does $\ce{Ni((en)2(Cl)2)}$ show cis-trans form ? And if No Why not ?
2
votes
2answers
1k views

What tools are used to predict the products of a chemical reaction? [duplicate]

I was wondering if there is a decent and non-complex way to predict the outcome of mixing two chemicals together. I know that molecular dynamics is used in computational chemistry to understand ...
3
votes
1answer
3k views

What is the accuracy of scf=qc when convergence criteria is lowered?

I am trying to run single point calculations with Gaussian 09 for a Mulliken population analysis on large graphene/graphite (940-1411 atoms) sheets/clusters. I was having difficulty with memory ...
9
votes
2answers
7k views

What's the physicochemical difference between a chromophore and a fluorophore?

Let's take Hematoxylin, which is a pH indicator and a stain for histology, and therefore a chromophore, but does not fluoresce: Now let's take Eosin, which stains tissue pinkish, but is also ...
2
votes
3answers
2k views

Avogadro - How can bonds be hidden and only show atoms?

I am using Avogadro for visualizing some cluster systems. Is there a way to hide the bonds of the system, ie. only showing atoms? Thanks!
0
votes
1answer
153 views

chemical equilibrium reaction for burned gases in engine

I do not understand how equation(3) occurs.(taken from the book Internal Combustion Engines by John B.Heywood) $$ $$ Consider a reactive mixture of ideal gases. The reactant species $M_a,M_b$ etc.and ...
3
votes
1answer
140 views

How did Scientists Capture The First Images of Molecules Before and After Reaction?

Using a state-of-the-art atomic force microscope, the scientists have taken the first atom-by-atom pictures, including images of the chemical bonds between atoms, clearly depicting how a molecule's ...
5
votes
4answers
3k views

Open Source tools to draw a set of 2d molecular graphs from sdf file

I have a sdf file for around 50 small-molecules for which I am doing structure-activity study. I would like to draw 2d graphs of all the molecules such that the image would fit into a single journal ...
0
votes
1answer
1k views

Nomenclature of alkenoic acids - which group has priority: the alkene or the acid?

Right, how do you systematically name them? Also, do you number them from the double bond end or the Carboxyl end? Ie would it be something like. 2-methyl Hept-3-enoic acid? Scuse the bad question ...
7
votes
2answers
602 views

Create my own solar cells?

How would I grow my own and build functional solar cells? I've read and researched that they're mostly a crystal structure of something like silicon. I would assume I'd be able to grow my own crystals ...
2
votes
2answers
2k views

What is a "Strong" Acid?

If a reaction requires a "strong" acid - what does this mean? Does it mean any acid of a specific concentration or pH? Are only certain acids classed as "strong"? I have read on Wikipedia that it ...
5
votes
2answers
3k views

Finding Pv in Pv=nRT for molecular hydrogen

I'm attempting to write a small program that will calculate the values for the Ideal Gas Law, specifically for molecular Hydrogen (H2) in space. Eventually, this will grow to be a sort of "simulator",...
1
vote
2answers
130 views

How do the differences in the number of protons result in such great differences in elemental properties?

I understand(I think) the mass and density aspect, i.e. the more protons you have, the more the element weighs, also the denser the atom is. What about everything else(color, for example)? Elements ...
6
votes
3answers
334 views

FCI implementation

Could you suggest, please, a manual/textbook/tutorial for implementing FCI (full configuration interaction) method on computers. I am interesting in algorithms mainly. I would like to write my own ...
7
votes
2answers
35k views

what is a pseudohalogen/pseudohalide?

What do you mean by a pseudohalogen/pseudohalide and how do you tell whether a molecule/ion is a pseudohalogen/pseudohalide ?
1
vote
1answer
745 views

Specific latent heat of fusion of a noble gas

Could someone explain to me where the additional energy goes when applied to an object in the state of melting (such as water) so that the temperature of the object does not increase, and could ...

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