# All Questions

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### How can I work out the entropy change of benzene when it changes from vapour into liquid?

I'm stuck on a particular problem which I can't work my head around: Information has been given that :The boiling point of benzene at atmospheric pressure is 353 K and the enthalpy of vaporization of ...
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### Does the relationship equation between standard cell potential and equilibrium constant violate potential's intensive properties?

The equation: $$E^{。}_{cell}= \frac{RT}{nF}\ln K_{eq}$$ We all know cell potential is intensive, not affected by the amount, Because: $volt=\frac{joule}{coulomb}$. Both joule and coulomb will be ...
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### Gas Stoichiometry [on hold]

-If liquid carbon disulfide (CS2) reacts with 450mL of oxygen to produce the gases carbon dioxide and sulfur dioxide what volume of each product is produced? -Assume that 5.60L of hydrogen gas at STP ...
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### Gas Stoichiometry [on hold]

1 Carbon monoxide reacts with oxygen to produce carbon dioxide. If 1.0L of carbon monoxide at STP, how many liters of oxygen are required to react how many liters of carbon dioxide are produced 2 ...
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### What is this reference material in spectrophotometry?

First, I should say I never have done any spectroscopies and I am just reading about it. As far as I know, UV-Vis spectrophotometer has 2 beam samples: sample and reference. The sample has very ...
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### What type of bonding occurs in isolated silicon?

Would isolated silicon engage in network covalent bonding as quartz does or would it engage in a different kind of bonding? Would germanium display similar qualities? *I am asking what is the bonding ...
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### Given a forward reaction with positive enthalpy, is its reverse reaction be endothermic or exothermic?

I'm pretty sure the sign changes. But, I want to be sure if it becomes endothermic or exothermic.
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### What is a catemer?

What is a catemer and how does it differ from a dimer? What type of compounds could form catemers and how does their formation influence its crystal structure?
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### Inorganic Chemistry: Lattice energy, Madelung constant and Born Exponent

I would like to know if you can find Madelung constants in the data book and how to work out the born exponent for ionic structures such as NaCl, Its something simple but i dont know fully ...
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### Problem in reasonning about aqueous solution

I have to build the stability diagram of mercury and I have a problem with this couple: $\ce{Hg^2+}/\ce{Hg2^2+}$ $E^\circ=0.91\ \mathrm{V}$ Exercise says that a the border the concentration is ...
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### How can I easily explain to a layperson the difference between types of “contains”

I had a conversation with somebody who had somewhat confused ideas about food. He thought that "all food contains sugar" and when I gave a bottle of oil as the counterexample, he said the glycerol is ...
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### Why is glycine hydrochloride more acidic than chloroacetic acid?

I cannot figure out why glycine hydrochloride is more acidic than chloroacetic acid. Could I have figured this out from a pKa table and maybe am just not seeing it? On the table I have in my book ...
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### Buffer solution calculation

Preface: Buffer solution (acid-base buffer). I am provided with a weak base, which I will designate B. pKa for B's conjugate acid--which I will designate BH--is 8.1, and its mole weight (sic) is ...
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### Factors affecting fluorescence in organic molecules

Rhodamine is a fluorescent dye. What features of the molecule result in it being so highly fluorescent ? I assume the extended conjugated system with a stabilized first excited state is necessary, ...
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### Determining Aromaticity?

Could someone help me determining the aromaticity of the compounds? My Attempt: (i) not an aromatic compound since it only has 4 pi electrons that does not satisfy Huckels (4n+2) rule (ii) not ...
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### Can we prevent metal corrosion by creating a vacuum around it?

I have a device in a box which has parts of metal. So can I prevent corrosion by creating a vacuum around the metallic object?
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### Which Salts Contain Water Of Crystallisation? [on hold]

Which Salts Contain Water Of Crystallisation? For e.g copper(II)sulphate contains water of crystallisation
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### What is the CO2 content in the air in a compartment of air and water, as a function of temperature?

What is the graph of carbon dioxide ($\ce{CO2}$) content in the air in a compartment consisting of 80 percent air and 20 percent ocean sea water as a function of temperature, in the temperature range ...
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### Effecting Chemical Change

Apologies in advance as I am not a science person by any definition. By most, I'm probably not a person but we'll let that be. I am studying the notion of "change" in things and focusing on chemical ...
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### a chemical model for pde

Consider the initial boundary value problem $$u_t=a(t)u_{xx},\,\,\,0<x<1,\,\,\,t>0$$ $$-ku_x(0,t)=hu(0,t),\,\,\,t>0$$ $$u(1,t)=u_0,\,\,\,t>0$$ $$u(x,0)=f(x),\,\,\,t>0$$ where ...
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### Is a Vmax value of 0.79 high or low? [on hold]

Is a Vmax value of 0.79 considered high or low? And what does it say about the enzymes parameters?
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### Cohesive Energy Density table request

Quick question: Any one knows a resource for Cohesive Energy Density of some organic materials ? I am not looking for any specific molecule, actually I want to plan my project based on available ...
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### What radius best represents reaction distance?

Molecules must be within a certain distance for a reaction to begin as well as satisfying a myriad of other factors. Whilst the exact distance varies from reaction to reaction, is their any ...
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### Gaussian Convergence Issue for N2+N PES

I am trying to obtain a potential energy surface (PES) for $\ce{N2 + N}$ combination using scan feature of Gaussian. I have tried different combinations of basis ...
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### Stereochemical aspect of heating of cyclohexane-1,2-diol

Does stereochemistry play any role in the heating of Cyclohexane-1,2-diol? If I remember correctly, different products are formed depending on whether the diol is cis or trans. (I think the products ...
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### Why does an acid salt possess acidity as well as basicity?

For example, $\ce{BaHPO_{4}}$ has acidity of 2 and basicity 1. Why does this so? Its basicity is 1 because it has 1 replaceable hydrogen ion. But why does this have acidity?
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### Why are the axial bonds of PF5 longer than those of the equatorial bonds? (Hybridization)

The axial bonds of $\ce{PF5}$ are longer than those of the equatorial positions. One explanation is that because the axial bonds are experiencing more repulsion than those of the equatorial and ...
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### Accelerated Oxidation Of Iron When Coating Breaks

I was presented with the following information: If iron is painted, then oxygen and water are prevented from contacting the metal, and corrosion is avoided. Sometimes the iron is coated with a thin ...
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### Equation for Solubility equilibrium [on hold]

When 1.0M NaCl is added to a saturated solution of AgCl, a white precipitate forms. Write the equation of the equilibrium involved, and use this equation to explain the above observation.
I have this question that is from my textbook that is very confusing to me. A $1.00~\mathrm{L}$ solution saturated at $25~^\circ\mathrm{C}$ with Lead(II) iodide contains $0.54~\mathrm{g}$ of ...
A student mixed several solutions of $\ce{Ba(NO3)2}$ and $\ce{NaF}$ until a precipitate begins to form. The following data were recorded: Equilibrium $\ce{[Ba^2+]}$. Equilibrium ...