# All Questions

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### Melting point-general chemistry

This one has stumped me for a few days. What is the specific name of the general chemistry principle that is responsible for the difference in melting points of pure and impure solids. I have ...
57 views

### Platinum vs Silver as Electrode for carbonic acid electrolyte [duplicate]

Is silver a better cathode electrode with carbonic acid in a galvanic cell or is a platinum electrode better with carbonic acid ? The anode electrode is copper with copper sulfate electrolyte, and the ...
309 views

### Can the first ionization energy for a specific element be calculated?

I'm taking a first-year Inorganic Chemistry course in college, and stumbled upon this problem: For $\ce{Mn}$ and $\ce{P}$, calculate the first ionization energy and explain the difference between ...
416 views

### Liquid that looks like smoke when bottled?

I am making a gift that will consist of a liquid in a sealed bottle. I want the liquid to have a magical appearance. Something like the appearance of smoke - varying opacity from almost clear to ...
6k views

### Positive vs. negative heat of solution confusion

Given that I have absolutely zero formal (or informal) education in chemistry (sorry about that), I'm struggling to get my head around what appears to be repeated confusions of the term "heat of ...
13k views

### Preparation of picric acid

My textbook says "Nowadays picric acid is prepared by treating phenol first with concentrated sulfuric acid which converts it to phenol-2,4-disulfuric acid and then with concentrated nitric acid to ...
296 views

### Replacing air with nitrogen in a drum.

I have a 55 gallon drum half ful of liquid. I would like to put a "blanket" of nitrogen over the liquid. How can I replace the air in the drum with nitrogen?
92 views

### How can be explained why the specific heat of ice is twice as low as liquid water?

To raise the temperature one degree of ice costs about 2000J but for liquid water it is 4000J. The reason for that is that the freedoms of vibrations rotation and translations of ice are lower and the ...
248 views

### Distinguishing among SN2/SN1/E1/E2 for a secondary bromide

a. 2-Bromo-3-phenylbutane reacts with $\ce{NaOMe}$ in methanol. What is the mechanism? b. This compound then reacted with $\ce{CN-}$ in DMSO. What is the mechanism? My Attempt a. I am debating ...
43 views

### Why do electrophillic addition reactions (between hydrogen halides and alkenes) happen?

I understand that the type of solvent (protic or aprotic) may impact the rate of the reaction, but why doesn't the hydrogen just stick with the halide in the first place? I'm not sure if the reason ...
2k views

### Thermodynamic and kinetic products - carbocation stability

The professor wants to know which is the thermodynamic product and which is the kinetic product. He says there are only two products - the two on the right that result from the resonance-stabilized ...
368 views

### Why did my deep eutectic solvent solidify?

I'm finally getting around to beginning to test this deep eutectic electrolyte. I mixed choline chloride with urea in a 1:2 mole ratio in a glass container. It formed a sludge. I sealed the ...
5k views

### Why is the enthalpy of solution for NaCl 3.88 and not 4.1 kJ/mol?

Based on Hess' law, the molar enthalpy of solution is equal to the sum of the enthalpies of formation of products minus reactants. In the case of dissolving table salt ($\ce{NaCl}$) in water, those ...
89 views

### How to dilute a stock solution when the resulting solution has a smaller volume? [closed]

Describe how you would dilute $2.0~\mathrm{L}$ of a $0.85~\mathrm{mol/L}$ magnesium hydroxide stock solution to make $200.0~\mathrm{mL}$ of $0.30~\mathrm{mol/L}$ magnesium hydroxide. I know the ...
148 views

### Can I use fluorescence microscopy with a solution of hydrogen peroxide?

I want to use microspheres which have been dyed with a fluorescent dye for fluorescence microscopy in a solution that has a 1-5% concentration of hydrogen peroxide. Is this possible or will the ...
5k views

### Relative rates of two acyclic dienes in the Diels-Alder reaction

As for factors that affect the rate of the Diels Alder reaction, having an s-cis conformation is primary. But in a case as shown below, what makes the second diene react faster compared to the third? ...
752 views

### Stability of CN molecule

The $\ce{CN}$ molecule has been observed spectroscopically in comets where pressure has been estimated to be as low as $10^{-10}\ \mathrm{mmHg}$. Draw a Lewis structure for $\ce{CN}$. Suggest an ...
8k views

### What is the correct Lewis structure for calcium phosphate?

In calcium phosphate, $\ce{Ca3(PO4)2}$, since the calcium and phosphate share an ionic bond, and the phosphorus and oxygen share a covalent bond, should the Lewis structure be like the following? ...
6k views

### Sensitive test for lead in water?

Some of my friends are in Flint and I'm horrified by their situation. I would like to learn how to test for lead independently. After all if you can't trust the state sending them water to test is ...
387 views

### How many valence are in each molecule? [closed]

I have Benzene, Dewar Benzene, Prismane, and 1,3,5 cyclohexatriene (which looks just like benzene but with different lengths between the $\ce{C-C}$ bonds). They are all $\ce{C_6H_6}$ chemical ...
242 views

### Fermentation of different types of sugar

I'm searching for the difference in the fermentation of muscovado sugar, honey and sugar cane. I have used a specific microbiota to to ferment these three types of sugar and have to explain why I've ...
2k views

### Role of the counter/auxiliary electrode in cyclic voltammetry

I am doing a school project on cyclic voltammetry and am currently studying the topic. I have learnt that the reaction mostly takes place around the working electrode where the current is measured ...
2k views

### Increasing Covalent character increases Colour intensity

I observed some trends as follows:- $\ce{PbCl2}$ white and $\ce{PbI2}$ yellow $\ce{SnCl2}$ white, $\ce{SnCl4}$ red and $\ce{SnI4}$ black $\ce{AgCl}$ white, $\ce{AgI}$, $\ce{AgBr}$ and $\ce{Ag2CO3}$ ...
3k views

### Why is Hessian Matrix called 'force-constant' matrix?

Hessian Matrix is a square matrix containing the elements as the second-order partial derivatives of energy-function of a molecule; the derivative is done with respect to geometric coordinates of the ...
196 views

### If there is more than one branch in a hydrocarbon, which branch do you name first?

I have read that branches need to be named in alphabetical order, but I do not really understand this, or do you start with the branch closest to the edge of the hydrocarbon?
323 views

### When naming hydrocarbons, when do you number the branch or double bond? [closed]

I have realized that not all chains and double bonds are numbered. I have noticed that up until 3 carbons in a chain, the double bond is not numbered, but I am not sure about the chain.
1k views

### How does ice melt?

I know that when water freezes, it forms a crystalline structure created by the hydrogen bonds between polar water molecules. Also, I know that during a phase change, the potential energy of the ...
1k views

### why are cyclic dienes much more reactive?

Cyclic dienes are very reactive, for example cyclopentadiene in room temperature, it even dimerizes. What is the factor that indicates such reactivity of cyclic dienes ?
145 views

### Speed up polymerisation of formaldehyde

Is there a way to speed up the formation of para-formaldehyde in a formalin solution?
111 views

### Are elemental compounds composed of different isotopes polarised?

Are elemental compounds composed of different isotopes polarised? I'd expect any such effect would only really be noticeable for very light elements such as hydrogen. I'm not sure which way the ...
16k views

### Why do SN1 reactions prefer tertiary carbons?

I can understand that $\mathrm{S_N2}$ reactions prefer primary carbons, because of the steric hindrance that would be an obstacle. But what is the exact reason that $\mathrm{S_N1}$ reactions prefer ...
125 views

### Do SN1 reactions have dependency on the nucleophile?

'The rate of the reaction of tertiary butyl bromide with the hydroxy ion is dependent on the concentration of the tertiary butyl bromide, but is independent of the hydroxy ion.' This means that the ...
858 views

### Why do SN1 reactions happen slowly?

'The first step where the carbonium ion forms is slow and because it contains only the halogen, the general speed of the reaction will be slow.' I don't understand why should SN1 reactions happen ...
I know the product of $\ce{CO2 +H2O}$ yields $\ce{H2CO3}$. This is a reversible equation so $\ce{H2CO3}$ goes back to $\ce{H2O + CO2}$. However, my question is: Is there a certain pH which will ...