All Questions

4
votes
2answers
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. ...
5
votes
4answers
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 ...
5
votes
2answers
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 ...
15
votes
2answers
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 ...
8
votes
3answers
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 ...
1
vote
1answer
20k views

What is the right quantum numbers of Copper?

Copper have $[Ar] 3d^{10} 4s^1$ electron configuration. And Zinc have $[Ar] 3d^{10} 4s^2$ electron configuration. My question is, what is the right quantum numbers of last electron of copper? Is it $$...
2
votes
1answer
3k views

What makes Gold so different from Platinum? [closed]

Looking at Wikipedia, Gold & Platinum are in adjacent seats. ...
16
votes
2answers
60k views

EZ-Water - Fraud or breakthrough?

Recently the quack medicine folks online have been promoting the research of a certain Dr. Gerald Pollack who claims to have discovered a "forth phase of water", and who has recently published a book ...
17
votes
7answers
42k views

Why can't pure water conduct electricity since it can be reduced at cathode and oxidised at anode?

We all know that pure water can't conduct electricity. But during electrolysis, if add a small amount of $\ce{HCl}$ acid inside, water could be decomposed to hydrogen gas and oxygen gas, as it is ...
6
votes
1answer
9k views

How many electrons can an orbital of type f hold?

I was taking a chemistry test and I encountered the following question: How many electrons can an orbital of type f hold? A. 6 B. 10 C. 2 D. 14 E. 1 Since there can be [-ℓ, ℓ] ...
27
votes
3answers
23k views

Why do salts such as NaCl dissolve?

If we look at solubility of salts in water, we are told that they disassociate, because the positive $\ce{Na}$ ion is attracted to the partially negative oxygen in water and the negative $\ce{Cl}$ is ...
2
votes
1answer
1k views

Flory Huggins Theory

For an ideal chain, Flory Huggins theory gives us a distribution which is like a Gaussian. $$P(l, r) \sim \left(\frac{3}{2 \pi l^2}\right)^{3/2} e^{\frac{-3 r^2}{2 l^2}}$$ where, $l$ is the monomer ...
1
vote
1answer
7k views

Difference between 18 electron rule and effective atomic number rule

Is there any difference between 18-electron rule and effective atomic number rule? Both rules are based on attainment of a noble gas configuraion as a criteria for stability of complexes. Besides, ...
10
votes
2answers
3k views

Which are the differences between resonance Raman and fluorescence?

If the fluorescence is the re-emitting of a photon with a larger wavelenght due to the transition from a higher energy state to a lower energy state the case of resonance Raman (where there aren't any ...
7
votes
1answer
247 views

Solvation of uranyl formate/acetate

Uranyl formate has a structure something like: $\ce{UO2-(OCHO)2}$ So the structural formulae I've seen have two double-bonded oxygens directly attached to the U and each formate group is attached by ...
11
votes
2answers
724 views

Regarding logic behind Organic Chemistry [closed]

Was there any logic or thinking behind the experiments performed by Cannizzaro, Beckmann, Gattermann, Koch etc.? Did they thoughtfully perform experiments or just add any two reactants and luckily ...
3
votes
1answer
144 views

Special electron configurations in p block on periodic table?

Gold and Chromium have weird electron configurations, because electrons are differently divided : eg an electron jumps from a s-orbital to a d-orbital to have a half-filled s orbital and a fully/half ...
4
votes
1answer
6k views

Finding electron configuration of lanthanide ions

When I have a gadolinium ion ($\ce{Gd^3+}$), how can I calculate its electron configuration? $$\ce{Gd} : \mathrm{[Xe] (4f)^7 (5d)^1 (6s)^2}$$ Do I need to first subtract the 2 electrons in the $\...
6
votes
2answers
383 views

Analytical solution to first-order rate laws

Does anyone know the analytical solutions to the following rate laws: 1) $\frac{\mathrm{d}\rho_\text{W}}{\mathrm{d}t} = -\rho_\text{W} \cdot (K_1+K_2+K_3)$ 2) $\frac{\mathrm{d}\rho_\text{T}}{\mathrm{...
4
votes
0answers
82 views

Is there a kind of table about configurations similar to the example I gave below?

If MALDI is used as an ionization method, then TOF as an analyzer is suitable since the MALDI creates singly charged ions which have high m/z ratio and only TOF can analyze that ions, and multichannel ...
3
votes
2answers
2k views

How to determine an oxidation number of an atom in the compound, that has at least two elements, which are not hydrogen or oxygen?

Wiki says: [Oxidation state] is defined as the charge an atom might be imagined to have when electrons are counted according to an agreed-upon set of rules: The oxidation state of a free ...
2
votes
0answers
450 views

Why does the reaction of chlorosulfonic acid (colorless) and 1-dodecanol (colorless) produces a deep dark-red-colored solution?

I was wondering if anyone had any insight as to why the reaction of chlorosulfonic acid (colorless) and 1-dodecanol (colorless) produces a deep dark-red-colored solution? The reaction should give ...
2
votes
0answers
114 views

Shift of the null half-reaction potential

If we change the null half-potential, would it change half-potentials of other half-cell reactions by the same amount, so that voltages of net reactions stay the same?
2
votes
1answer
98 views

Why do molecules have to first transform to gas before doing a reaction?

I have to calculate the enthalpy of the reaction $$\ce{Cs(l) + 1/2I2(s) -> CsI(s)}$$ and the answer is $$\Delta H_f = \Delta H_{vap}^{\ce{Cs}} + \frac{1}{2}\Delta H_{subl}^{\ce{I2}} + \frac{1}{2}E_{...
0
votes
3answers
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 ...
2
votes
1answer
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?
2
votes
0answers
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 ...
11
votes
2answers
22k views

Difference between Reaction Rate and Rate Law?

Lets say you have the reaction $$\ce{$a$A + $b$B -> $c$C + $d$D}$$ The rate of the reaction is given by the change in initial concentration over the change in time. $$-\frac{\Delta \left[\ce A \...
0
votes
2answers
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,...
2
votes
3answers
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 ...
4
votes
1answer
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: ...
0
votes
0answers
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: $\ce{2CH3COOH + CuO -> (CH3COO)2Cu + H2O}$ ...
9
votes
2answers
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 ...
3
votes
1answer
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? ...
1
vote
2answers
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, ...
6
votes
1answer
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.
3
votes
0answers
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+....
15
votes
2answers
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 ...
3
votes
2answers
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 ...
41
votes
2answers
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 ...
2
votes
1answer
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 ...
2
votes
1answer
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 ...
6
votes
3answers
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 ...
8
votes
1answer
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 ...
1
vote
1answer
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 ...
2
votes
2answers
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^...
3
votes
1answer
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?...
7
votes
1answer
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 ...
5
votes
1answer
35k views

Lines on inside of hexagonal shapes of structure diagrams

just a simple question from me today... I was looking at the structure of Norepinephrine for a school project and was curious about the diagrams on the Wikipedia page for it. I was wondering why ...
8
votes
3answers
7k views

Activity of hydrogen ion

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 ...

15 30 50 per page