# All Questions

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11 views

### Organic Chemistry Solubility Question [closed]

Question: The solubility of “Compound Z” in boiling ethanol (78 C) is 0.20 g/mL and 0.01 g/mL in cold ethanol (0 C). a. What is the minimum amount of ethanol required to recrystallize a 5 g sample of ...
14 views

### Quantifying location and volume of "lone pairs" for VSEPR

Of course molecular shape and the VSEPR model come up frequently. As discussed previously in a valence bond picture like VSEPR, the lone pair electrons are closer to the atom than bonding pairs, and &...
30 views

### How could we synthesize tert-butyl-alcohol, starting with just methane as only carbon source?

would it be possible to synthesize tert-butyl-alcohol with methane as the only carbon source? I mean, I almost figured it out, so basically methane is radically substituted by bromine under UV, then ...
82 views

### Why doesn't the protonated propyne rearrange?

In the reaction of propyne with $\ce{HBr}$ this cation (prop-1-en-2-ylium) was mentioned by my teacher: $$\ce{H3C-\overset{+}{C}=CH2}$$ He told me that the carbocation will not rearrange as it will ...
37 views

### Acidity of triphenylmethane

The question is : Why does triphenylmethane have such a high pKa value (going up to $33$) My reasoning suggests that the conjugate base is highly stabilized and hence triphenylmethane should be a ...
26 views

### Conversion from Spectral Line Intensity to Absorbance (HITRAN)

The HITRAN spectral database gives access to the spectral absorption lines of various gaseous species. These lines are given as $S$ values in units of $cm^{-1}/(molecule·cm^{-2})$ (or $cm.molecule$). ...
27 views

### Spin contamination and expansion of unrestrict determinants

I was studying with the book "Modern Quantum Chemistry" of Sazbo and Oustland. In the chapter 2, they talk about unrestrict (UR) determiants. It's explaneid that UR determinants are not ...
58 views

### How can a catalyst be selective if it does not change the equilibrium constants?

\begin{align} \ce{CO(g) + 3H2(g) &->[Ni] CH4(g) + H2O(g)}\\ \ce{CO(g) + 2H2(g) &->[Cu/ZnO-Cr2O3] CH3OH(g) }\\ \ce{CO(g) + H2(g) &->[Cu] HCHO(g) } \end{align} As we see here, ...
32 views

### Butane and Isopropyl burners in same classroom [closed]

Can I have students use a butane burner and an Isopropyl alcohol burner in the same classroom. I need 12 stations but only have 6 of each type.
22 views

### How displacement reaction actually taking place?

"When a zinc plate placed in copper sulphate solutionfor some time,after sometime we can see holes in plate , why?" So this was a question in my book , I don't want answer of this one. But I ...
19 views

### Reaction of 1-Bromo-1-phenylethene with two equivalents of LDA

I was confronted with the reaction of 1-bromo-1-phenylethene with two equivalents of LDA, then the product is hydrolyzed. As it is a bulky base, it will surely deprotonate and form the phenylacetylene,...
18 views

### Energy of reactants and products [closed]

In some reactions, energy is released and when I want to understand the reason for the release of energy, I find that the energy of the products is lower than that of the reactants. But What is this ...
8 views

### What is meant by "analogous reactions" in the Bell-Evans Polanyi Principle?

The BEP principle says that for analogous reactions, enthalpy change and activation energy are linearly related. What is meant by analogous reactions? Eg. For electrophilic addition of HBr to pent-1-...
15 views

### When is the adsorption energies equal energy of the first layer and the energy of the second layer? [closed]

When is the adsorption energies equal energy of the first layer and the energy of the second layer??
86 views

### What's the major Product? [closed]

I was thinking, would the bromine add to the more substituted Carbon due to selectivity?
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### Impact of flow rate on peak areas in Mass Spectrometry

As a follow up to the discussion in comments: it's now clear that UV peaks will have larger area if flow rate is decreased, because the same portion of molecules are measured again and again. With ...
21 views

### Why exactly is the conduction band in semiconductors conducting?

Is it because when the electrons are excited to a higher energy level, they can lose energy and fall back down to lower energy levels? Due to the sheer number of antibonding MOs in the conduction band,...
86 views

### Isn't hydrogen chloride a salt, because it is an ionic compound? [closed]

So I just learned in chemistry that salts are ionic compounds. Shouldn't, $\ce{H+Cl-}$ be a salt since hydrogen ion has positive charge and chloride ion has negative charge? If $\ce{HCl}$ is a salt ...
14 views

### Properties of Gases and Gas Law [closed]

A gas occupies a volume of 80.0ml and 630torr. At what temperature in °C would the pressure be 770 torr if the volume remains constant?
27 views

### Why is the enthalpy of solution of hydrated calcium chloride positive?

My book says that the enthalpy of solution of anhydrous calcium chloride is negative because it produces hydrated calcium chloride. But when hydrated calcium chloride is dissolved in water, the ...
21 views

### How to "draw" a coordination bond (dashed bond) in MOLFILE?

How can we "draw" a coordination bond (dashed bond) in MOLFILE? I cannot find a bond property or option that would allow me to choose such a thing. So many drawings of organo-metallic ...
553 views

### Do solid phase pH buffers exist?

I want to buffer the pH of my solution but I don’t want to add any mobile solutes. I imagine that large molecular mass buffers could be used such as phosphorylated polysaccharides or proteins. The ...
14 views

### Does addition of reversible and irreversible reaction gives a reversible reaction or irreversible reaction? [closed]

There are 2-3 questions related to it . Does every reaction has a equilibrium constant ? (even the irreversible one's ?) I have read that any acid having pKa < -1.7 dissociates in water ...
19 views

### CaOCL2 Question [closed]

Calcium hypochlorite is completely dissolved in deionized water to make 2L of solution. The concentration of Ca2+ is 200 mg/L. What mass of calcium hypochlorite (Ca(OCl)2) was dissolved in the water? ...
23 views

### General cleaning solution for clinical chemistry applications

I want to reuse some plastic and glass items that I am using to do colorimetric concentration analysis of serum and urine. There are some enzymatic assays, mineral assays and so on. I have been trying ...
279 views

### How can we synthesize this cycloester, starting with methyl 4-phenylbutanoate?

I was wondering how to realize following synthesis: I am struggling with this one; for sure, this has something to do with the benzyl position which is particularly reactive, and something ...
13 views

### Electrophilic addition when both phenyl group and alkene is present [duplicate]

Actually my doubt is that why the answer is C? I proceeded through markonikov addition, Carbocation formed on 2nd Carbon from benzene ring, did a rearrangement as the carbocation gains stability due ...
65 views

### What is the mass of a proton?

My textbook explains that the deviation from integer atomic mass is caused by mass difference between proton and neutron, which are $1.67262·10^{-27}$ kg and $1.67493 ·10^{-27}$ kg, respectively. If ...
17 views

### Chemical structure of Indole-3-Carbinol [closed]

How would you describe the chemical structure of Indole-3-Carbinol pictured above?. Thanks!
282 views

### What is the colour of cesium?

I am confused with the color of cesium. Some websites and books say that it is a silvery white metal, and some say it has a golden colour, and some say it has a silvery golden colour. Among these ...
87 views

### LEED - determining surface structures

How can one describe surface structures (before and after adsorption)? I understand the diffraction theory but I have never really tried to determine the structures of samples by myself. LEED (low ...
40 views

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### Synthesis of allylic ether, starting with phenalene

I stumbled across a retro-synthesis question, for which I don't know the exact answer; I prepared two synthesis ways, but I don't know if they could be realized in a lab. The question is the following:...
52 views

### Why do Atoms Come Close to form Molecules? [closed]

I am confused in the topic related to formation Of molecules from Atoms,Why do the Two atoms come close to each other,For example Every Neutral atom has equal number of Electrons and protons ,hence ...
10 views

### Determine the mass of Zinc [closed]

I have ordered a tub of zinc metal pieces and I am concerned that the zinc is not pure. It is your task to determine the % purity of the zine pieces. Determine the mass of zinc in one of the zinc ...
15 views

### Lithium Carbonate Powder Thermal Conductivity [closed]

What is the thermal conductivity of lithium carbonate powder?
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### Is the exothermic reaction that happens when we add water to acid because of the dissaciation of ions? [duplicate]

I've been wondering why should you add acid to water and not the other way around. I would like the point that , "this is because of the dissociation hydrogen and chlorine ions" to be "...
52 views

### Birch Reduction of Benzene with sodium in liquid ammonia [closed]

I had a question with the following reaction sequence: For the first step, what I did was the following: However, the answer is shown to be his one: Please explain why the free radical rearranges ...
307 views

### What is the pH of the universal indicator?

I know that the universal indicator is a solution of various pH indicators used to find out the pH of a substance by displaying different colors. But, what is the pH of the universal indicator itself? ...
24 views

### Some research groups offer notes e.g. myers and evans. Does anyone else have any other good research group note recommendations for organic chemistry? [closed]

I am interested in protecting groups, reductants, and oxidants (I'm not looking for textbook recommendations though, I wanna read notes) Thanks in advance!
28 views

### Does overlapping partial density of states indicate formation of chemical bond?

Does overlapping partial density of states of two adjacent atoms indicate formation of chemical bonds between the two atoms? The partial density of states here means the density of states of an ...
29 views

### Is zinc chloride a viable substitute for zinc cyanide in brass plating processes?

I am owner/operator of a small plating company in Pittsburgh, Pa. I am having a problem with reddish color in brass plating process. Obvious cause is low zinc content in brass plating bath. Our ...
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### By what chemical process does shellac in alcohol degrade over time?

It is well established that shellac dissolved in alcohol ('liquid shellac') has a limited shelf life. The actual shelf life is highly variable, depending on the source, manufacture, storage. But after ...
13 views

### Chem reaction final product [closed]

When mixing baking soda and apple cider vinegar for ingestion.. does the chemical reaction nullify the detoxifying effects of each product or does it just neutralize the acid. Like.. what to they ...
33 views

### Does nascent Oxygen/Hydrogen really exist or just or is it just electron from ionic equation? [duplicate]

Recently I was taught by my teacher that there is no such thing as nascent oxygen neither hydrogen. It just represents Electrons from ionic equations. Then he proceeds to give example of following ...
30 views

### Why does the side with more moles of species always get affected the most in pressure/volume, and dilution changes?

I understand how LCP works in favouring the side with more moles of gas, if the imposed change is a decrease in pressure. Or vice versa, if the imposed change is an increase in pressure the side with ...
23 views

### Novalucol back titration lab calculations

I had a lab today where we had the goal of figuring out how many moles of HCl were neutralized by one tablet of Novalucol. Novalucol is an antacid tablet containing magnesium hydroxide and calcium ...