# All Questions

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### Stoichiometry: efficiency

My book gives me the following problem: "A mixture of $125.0 g$ $\ce{N2}$ and $32.0 g$ $\ce{H2}$ reacts to $36.5 g$ $\ce{NH3}$. Calculate the efficiency." My method to do this is - one I learned from ...
5answers
22k views

### Oxygen or carbon with a positive charge? (comparison of canonical structures)

Which of the contributing structures of the resonance is more stable? I'm watching a video lecture by a professor of my college where he puts this question to the class. The class unanimously ...
1answer
3k views

### Calculation of Atomic weight percentage in AAS

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

### Are there any tricks I can use to pull SO2F2 out of the air?

A massive apartment complex near where I live is being fumigated with Vikane gas (sulphuryl flouride, $\ce{SO2F2}$). The process will take a long time (weeks) because there are a lot of buildings, ...
1answer
13k views

### Why is there a difference between O2 and B2 sigma 2p molecular orbitals in diagrams?

The molecular orbital diagram for $\ce{O2}$ says that the sigma 2p bonding molecular orbital is lower in energy than the pi 2p bonding molecular orbital. Why is this not the case in the $\ce{B2}$ MO ...
1answer
423 views

### Free automatic organic synthesis Linux command line program

I'm trying to find a free automatic organic synthesis Linux command line program which take mol or smile files as input. I have random molecules and I'd like to know how difficult above a baseline ...
3answers
12k views

### Competing resonance and inductive effects in a substituted benzene

A molecule of phenol is much more inclined to under go an electrophilic substitution reaction than a molecule of benzene because the $\ce{-OH}$ group is highly reaction favoring. From what I ...
1answer
94 views

### What is an algorithm for making a net neutral molecule from a set of guessed positive charges? [closed]

Given a set of partial charges for the atoms in a molecule, which are educated guesses but do not add up to zero, we would like to zero them in an intelligent way. For example, if the net charge is ...
1answer
3k views

### Torsion angle symbol

I'm reading up on molecular modelling and have come across some terms I should probably have learnt a long time ago but always scared me off a bit with the Greek letters. I guess I'm a big boy now so ...
2answers
379 views

### How can I formulate a rate equation using a solid catalyst?

When formulating a rate a equation two experiments must take place: one in which the reactant concentrations are varied, and one in which the catalyst concentrations are varied. If I am given a ...
2answers
3k views

### Why sponge can't absorb mercury

Recently I have watched a video demonstration with a sponge and mercury and the sponge can't absorb mercury like it does with water. Why is that?
1answer
548 views

### Why polymorphs form?

We always hear about the different arrangements of molecules that lead to the formation of polymorphs, my question here is why would a polymorph form in the first place? The material was given enough ...
1answer
2k views

### Why are the total energies of transition states so commonly corrected for zero-point vibrational energy?

So often I see total energies of transition states corrected for zero-point vibrational energy which always confuses me. Zero point energy is the lowest energy that a ground state minimum energy ...
1answer
359 views

### Relating a compound's radii and unit cell dimensions

We're asked often to calculate the density of a crystal, and there is a known formula for that related to the unit cell volume. Now, for simple geometric structures such as the bcc structure (and ...
0answers
124 views

### How effectively bound Na2CO3 and BaCL2 water

How fast does $\ce{BaCl2}$ bind water from its surroundings, becoming a hydrate, compared with same process with $\ce{Na2CO3}$?
1answer
1k views

### Equilibrium between R and S configuration?

We have learnt that the energy evel of both R and S optical isomer of a compoud is same, just as well the entropy of each isomer is also same. If we consider the conversion of R form of a compound to ...
1answer
16k views

### How to find the concentration of potassium permanganate in this experiment?

I completed a titration experiment in a lab. The aim was to find the concentration of the titrant $\ce{KMnO4}$ solution by titrating it with a sodium oxalate solution of a known concentration. I ...
2answers
7k views

### Yellow-amber debris above water filter: What is it?

I have some weird, yellow-amberish pebbles that have been filtered by my Zero waterfilter. Any idea what they are? Copper maybe? The black stuff is charcoal from the filter. The quality of the water ...
1answer
250 views

### How did Halogens become known as Halogens? They are not the only elements that form salts!

Having never given it a though before, I recently discovered (in a different context) that the prefix halo- actually means 'salt' or 'sea' and the suffix -gen means 'to form' or 'to generate'. So the ...
2answers
419 views

### How can enzyme/substrate reactions that adhere (largely) to quantum theory also require 'Newtonian' consideration of gravity?

I'd just like to ask for a little clarification here due to confusion from interdisciplinary studies. I'm currently reading the 1976 paper related to the recent 2013 Nobel Prize for Chemistry, by 2 ...
2answers
41k views

### Is H2CO3 (carbonic acid) soluble or insoluble in water?

I am asking this because I know that acids are normally aqueous but according to the solubility rules, all carbonates are insoluble.
2answers
198 views

### Copper oxidation

In an experiment we conducted, we heated 1.6 grams of copper dust, and got 1.7 grams of oxidised copper, (it probably reacted with 0.1 grams of $\ce{O2}$) and our goal was to find which of the two ...
3answers
3k views

### LCAO (Linear Combination of Atomic Orbitals) and Phases

So when combining atomic orbitals to form molecular orbitals, you can either add the wave functions or subtract them. But at the same time, orbitals can exist in opposite phases (say one lobe of the p ...
1answer
3k views

### Do acids without hydrogen taste sour?

I have heard that acids taste sour because of hydrogen (I don't really know exactly). According to the definition of acids: An acid (from the Latin acidus/acēre meaning sour) is a chemical ...
0answers
78 views

### What Does the Equilibrium Constant represent? [duplicate]

If the Equilibrium constant stands for the extent of reaction at equilibrium, whether more of forward or backward reaction is taking place, then why is it not affected by factors like concentration of ...
1answer
163 views

### What is so special about quasicrystals?

Can whatever is special about quasicrystals be understood at A-Level standard or slightly above it? The material I saw online is either too layman or too advanced for me to follow. What practical uses ...

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