# All Questions

29,902 questions
241 views

### Which computational method/basis set should I use for small molecular ions?

I apologize for a perhaps newbie question. I would like to compute the potential energy surface for several small molecular ions, like $\ce{H2+}$ and $\ce{H3+}$, using quantum chemistry software. ...
9k views

### How do we actually know the chemical structure of a compound? [closed]

If a compound is placed before you and you are asked to determine what it is and what it's structure is, how do you actually do that? This might be a baby question for most of you but I am not from ...
3k views

### Can substituted acetone undergo Cannizzaro reaction?

I know the Cannizzaro reaction takes place in carboxyl compounds without $\alpha$-H with the regular examples being formaldehyde and benzaldehyde. But can this reaction take place with say ...
3k views

### Does freezing a solution with water always cause the water to separate and form the ice lattice?

I'm curious, I was trying to look into the affect of freezing a solution with water even when the solution is completely miscible. I came across something that detailed this regarding salt water and ...
2k views

### What non-toxic non-water substances have a freezing point very close to water's?

I was linked to a Kickstarter for a cooling ball to be placed in drinks which claims with constant marketing hyperbole how much it relies on "Phase Change" ! which is a neat concept and seems not ...
20k views

223 views

### Vacuum Distilled Medicine

If I were to buy/build a large still, that was air tight, and could hold a vacuum, and filled the reservoir with vegetable glycerin (which has a boiling point higher than the majority or desired ...
7k views

### How does partial reduction of esters to aldehydes occur?

Wikipedia says that esters can be reduced to aldehydes using DIBAl-H. Can anyone please explain how this reaction occurs?
199 views

### Finding one of the two unknown potentials with a given voltage of a net reaction

A half-cell consisting of palladium rod dipping into a $1\ M$ $\ce{Pd(NO_3)_2}$ solution is connected with a standard hydrogen half-cell. The cell voltage is $0.99\ volt$ and the platinum electrode in ...
22k views

### Difference between Reaction Rate and Rate Law?

Lets say you have the reaction $$\ce{aA + bB -> cC + dD}$$ The rate of the reaction is given by the change in initial concentration over the change in time. -\frac{\Delta \left[\ce A \...
100 views

### Balancing Oxidation-Reduction equations

Anode: $\ce{2 H2O_{(l)} -> O2 + 4 H+_{(aq)} + 4e^-}$ Cathode: $\ce{ 2 H2O_{(l)} + 2 e- -> H2_{(g)} + 2 OH-_{(aq)}}$ Can someone show me the steps for adding the two. For the overall reaction,...
604 views

### When should we not draw a Lewis dot structure?

My friend once told me that technically , we should not draw Lewis dot structure of molecules containing no central atom.(eg.benzene,acetic acid) Is he right ? If yes, then what is the reason behind ...
3k views

### Balancing the equation when MnO₂ is reduced to MnO by H₂(g)

I am studying for a final tomorrow and I was going through some problems on older exams and came across one which I wasn't really sure how to solve. The problem is to write the balance equation when: ...
6k views

### Why Add Salt to Vinegar to Clean Pennies? [duplicate]

One common cure for dirty pennies is to put them in vinegar and salt. The vinegar should react with the copper oxide on the penny in the following way: $\ce{2CH3COOH + CuO -> (CH3COO)2Cu + H2O}$ ...
2k views

### Have we ever created artificial metals?

I really don't know anything about chemistry, but I was wondering about the following vague question: has any substance been created that does not contain any metallic elements, but is metallic? In ...
580 views

### Electrode potentials at interfaces?

My questions relates to the fundamental concept of electrochemistry, more specifically the electrode potentials. 1) First, why is there a potential difference at the interface of two phases? ...
39 views

### Are phosphomonoesterases solid?

What state of matter are phosphomonoesterases? I am not a biochemist; while I've found various lists of such enzymes, and plenty of (to me) barely comprehensible articles describing their production, ...
23k views

### How much energy is needed to break a water molecule?

How do you calculate how much energy is needed to break a water molecule into its constituent atoms? note This is not homework. I just want to know what is required to get hydrogen out of water.
374 views

### How will the transference number of H+ ion in a dilute solution vary as temperature increases?

I know that transference number depends on Ionic mobility, which depends on temperature. But is there any equation which describes the relation of Transference number and temperature, any ions like H+....
782 views

### What utility does the Tau bond model of orbital overlap have?

In his book on molecular orbital theory, Molecular Orbitals and Organic Chemical Reactions, Ian Fleming notes that Pauling formulated an early alternative model to Huckel theory for explaining the ...
564 views

### How can I calculate the energy of a solution by knowing all of it's elements?

How can I calculate the energy of a solution by knowing all of it's elements? For example: If I have 2 liters of salting water $\mathbf{NaCl_{(aq)}+H_2O_{(l)}}$ contains 1.5 g of salt, how can I ...
33k views

### Does oil break down condoms?

It seems that every website on sexual health advises against using oil-based lubricants with condoms. It is claimed that "oil breaks down latex". One source claimed that a latex condom completely ...
1k views

### Why does sodium require energy to ionize?

If you look at $\ce{Na}$, it has a very low ionization energy, but the question is, why does it have an ionization energy at all? If it can get to the electronic configuration of $\ce{Ne}$, by losing ...
2k views

### Where does the extra electron go in ionic compounds?

In ionic compounds, where does the extra electron go? Or, in case of a cation, from which shell does it come? Consider, for example, $\ce{OH^{-}}$, where did this extra electron go in the electronic ...
2k views

### Why does chlorine undergo disproportionation in alkaline media?

One reaction used to form sodium hypochlorite (A type of bleach) is as follows: $\ce{2NaOH(aq) +Cl2(g)->NaOCl(aq) + NaCl(aq) + H2O(l)}$ Provided the sodium hydroxide is dissolved in some ...
188 views

### How should I modify my molecular dynamics simulation so that known chemical reactions can be modelled?

I have written some molecular dynamics code that I want to use to model known chemical reactions. By known I mean that it has been observed in a lab that $\ce{A +B->C}$. I am not interested in ...
254 views

### Size of dispersed phase particles in colloid?

I am really confused about what the size of particles of dispersed phase in a colloid is: one of my textbook says its between $1 - 100nm$, another says its between $1-1000nm$, and Wikipedia says its ...
239 views

### Do ions also form special electron configurations? (just as Copper and Chromium do)

Do ions also form special electron configurations? (just as Copper and Chromium do) I know that because copper has 1 electron in its s-orbital (highest) because it wants to have a full d-orbital (d^...
468 views

### Variation of cone angle with concentration of fuel-air mixture

A stoichiometric fuel-air mixture flowing in a Bunsen burner forms a well-defined conical flame. The mixture is then made leaner. For the same flow velocity in the tube, how does the cone angle change?...
3k views

### What is the colloidal osmotic pressure?

The oncotic pressure or colloidal osmotic pressure is the osmotic pressure developed due to the presence of colloids in a solution. But since the colloids are not true solution, why should the ...
I am not from chemistry background. Could you tell me in simple words what the activity of hydrogen $a_{\ce{H+}}$ is? It arises in the context that the negative logarithm of the activity of hydrogen ...