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2
votes
1answer
6k views

Reacting calcium with warm water and magnesium oxide with carbon dioxide, what are the products?

So I have several descriptions of reactions and I have to give the net ionic equation. Are these just the equations or are they the proper net ionic ones? Solid calcium is added to warm water. $$\ce{...
8
votes
2answers
13k views

Does hydrogen peroxide exhibit intramolecular hydrogen bonding interactions?

We know that intermolecular hydrogen bonding is seen in hydrogen peroxide $(\ce{H2O2})$. But is intramolecular H-bonding, i.e. hydrogen bond between an oxygen atom and a hydrogen atom attached to the ...
0
votes
1answer
3k views

How to estimate pH?

How you you calculate/estimate the pH of a solution with 3 components all of different pHs? Is there a paper describing this? For example: 0.1M Buffer PCTP at pH 9.5 1.6M Sodium Dihydrogen Phosphate ...
6
votes
1answer
4k views

How to calculate the heat capacity of a calorimeter based on a neutralisation reaction?

I've looked at the other similarly worded questions but I can't seem to make heads or tails out of them. So here's my case. I need to find the heat capacity of the calorimeter (in Joule/degree ...
12
votes
1answer
63k views

What is the definition of organic compounds?

According to the definition of organic compounds on Wikipedia: An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. ...
1
vote
1answer
8k views

What is Polymer Environmental Resin (PER)?

I'm no chemist and I probably wouldn't understand any technical answer but... I'm investigating the environmental impacts of various materials as compared to PVC and this is one that crops up ...
1
vote
1answer
660 views

Epimerization in peptide synthesis

How can epimerization during peptide synthesis be detected? And how can we change or modify the coupling conditions to stop epimerization occurring?
0
votes
1answer
788 views

What is the solid crud that appears inside my kettle?

Almost every share-house I've lived in has had some nasty looking solids collecting inside. I always regret looking inside the kettle because a cup of tea never tastes quite as good after you've seen ...
3
votes
2answers
184 views

Why is the nomenclature glucose 6-phosphate, not 6-phosphateglucose?

What exact nomenclature rule define the naming of glucose 6-phosphate?
1
vote
1answer
696 views

How do I find the thermal effect of this reaction?

I have graphite turning into diamond.I need to find the thermal effect of this reaction.How would one write that?I'm not sure how to proceed here.The teacher told us to use oxygen?
4
votes
1answer
117k views

Difference between conformational, constitutional, and structural isomers and the same and different molecules

Consider the following sets of problems: I was hoping someone could clarify what each checkbox means exactly. All of these answers are incorrect (except the first one with the check marks signifies ...
1
vote
1answer
818 views

why there is no simple rule to predict the possible ionic charges of element in middle of periodic table

I know element in left two columns have 1+,2+... and right ones 1-,2-. But in middle is all over the place. And with multiple charges. What defines that if this element is gonna have this charge. ...
3
votes
3answers
3k views

How do 1s and 2p orbitals overlap?

In the following figure we can see that the p-orbitals overlap 1s orbital (though relatively very little). How can an electron in p-orbital, be simultaneously in the 1s orbital at any given point ...
2
votes
1answer
1k views

What happens to the structure of tetracyclines when they expire?

I need to explain (chemically) why expired tetracyclines should not be used, relating to the changes in tetracycline structure that occur. All I can find is that they cause nephrosis, but not why.
1
vote
1answer
66 views

Is there a element that shows this pattern of boiling point?

Is there a compound that turns to gas at a certain temperature but if heated more turns back to liquid and if heated more than turn to gas? Does it exist naturally? Has a such a substance be found? ...
3
votes
2answers
2k views

Heat transfer dependence on temperature gradient?

Is the rate of heat transfer between two bodies brought into thermal contact dependent upon the different in temperature between them, assuming they each have the same mass? Imagine two bodies of ...
11
votes
4answers
19k views

Why do people still use the mole (unit) in chemistry?

I know that the mole is widely used in chemistry instead of units of mass or volume as a convenient way to express amounts of reactants or of products of chemical reactions. I'm wondering why people ...
1
vote
1answer
204 views

Boiling points of v. similar organic molecules

Given the similarity in formula between pentane ($\small\ce{CH3(CH2)3CH3}$, b.p. 36.2 °C) and neopentane ($\small\ce{C(CH3)4}$, b.p. 9.5 °C), why are their boiling points so different?
14
votes
2answers
14k views

How can aluminium oxide be called an acid?

Aluminium oxide is amphoteric. It is easy to see that it is a Brønsted-Lowry base through the following reaction: $$\ce{Al_2O_3 + 6HCl \rightarrow 2AlCl_3 + 3H_2O}$$ The aluminum oxide splits and ...
3
votes
1answer
966 views

Tools to draw molecular structure (wireframe) along with atom numbering

I am looking for open-source tools which can generate 2d molecular structure from the MOL or SMILES file. Further, it SHOULD number the atoms in the order of occurrence of atoms in the connection ...
8
votes
3answers
16k views

Which is most stable conformation of optically inactive butane-2,3-diol?

The most stable conformation of optically inactive butane-2,3-diol is: (A)  (B)  (C)  (D) I chose C as the correct answer but, in the answer key it is given to be B. C is the ...
0
votes
2answers
1k views

How do you draw (E)-1-phenyl-1,3-butadiene?

I'm having trouble drawing this molecule because I don't understand how the functional group Phenyl (by -ene suffix) can also be a substituent (by 1-phenyl). Also, what does the 1,3-butadiene mean?
1
vote
1answer
7k views

Why are more easily oxidized elements more reactive than less easily oxidized elements?

Why do the more easily oxidized elements displace the less easily oxidized elements? Question inspired by Activity Series of Metals
6
votes
2answers
18k views

Why does equilibrium constant change when the reaction is multiplied by a number and nothing in the real has been changed?

As far as I know, a large equilibrium constant shows that the a reaction like the one below wants to complete: $$\ce{B <=> A}$$ If A and B are gases, then K is: $$K_1=\frac{[A]}{[B]}$$ but ...
1
vote
1answer
2k views

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 ...
15
votes
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 ...
10
votes
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 ...
3
votes
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, ...
3
votes
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 ...
2
votes
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 ...
13
votes
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 ...
1
vote
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 ...
4
votes
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 ...
2
votes
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 ...
6
votes
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?
4
votes
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 ...
14
votes
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 ...
2
votes
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 ...
1
vote
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 $\ce{Na2CO3}$?
1
vote
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 ...
0
votes
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 ...
3
votes
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 ...
7
votes
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 ...
11
votes
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 ...
2
votes
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.
4
votes
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 ...
10
votes
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 ...
1
vote
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 ...
3
votes
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 ...
5
votes
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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