CHEMISTRY COMMUNITY

Vincent Kim 2I

it increases the rate constant of both reactions, but more substantially for the one with the higher activation energy

Vincent Kim 2I

carbonyls are C=O, and both ketones and aldehydes have a C=O bond

Vincent Kim 2I

k2/k1

Vincent Kim 2I

pH + pOH = 14

Vincent Kim 2I

R represents a carbon chain of any length

Vincent Kim 2I

Lavelle distributes the range of questions relatively evenly, but since we learned some new material after the last test, I'd watch out for those

Vincent Kim 2I

I'm pretty sure this fact will be given in a problem

Vincent Kim 2I

k' is the reverse rate constant of the reaction

Vincent Kim 2I

I may be wrong but I think it's because there's a coefficient of 2 in front of H+

Vincent Kim 2I

Raising the temperature increases the speed of the reaction, essentially increasing the rate constant

Vincent Kim 2I

Nucleophiles donate electrons just like a Lewis Base

Vincent Kim 2I

I think the constant volume refers to the entire container, as it doesn't change as the pressure increases or decreases inside, as it is a isolated system

Vincent Kim 2I

All the states should be given in a standard reduction potential chart

Vincent Kim 2I

The same goes for the other way around, the lower a substance's reduction potential, the better of a reducing agent it is

Vincent Kim 2I

I'm pretty sure you're correct, it shouldn't need to be written on the left side

Vincent Kim 2I

Coefficients are not in the cell diagram, only the chemical equation

Vincent Kim 2I

Yes, first order half lives apply to radioactive decay. Zero order and Second order half lives exist in real life with other processes

Vincent Kim 2I

Yes you can determine that the reaction is endothermic because the formation of one product is favored over that one product being broken up into two different molecules

Vincent Kim 2I

Unless the problem wants you to write it out specifically, probably not

Vincent Kim 2I

Usually on these tests, we are given the fact that the gases are ideal

Vincent Kim 2I

yes, this way delta H naught can be used for any amount of compound given, instead of the specific value that is produced when solving for simply delta H

Vincent Kim 2I

I think as a general rule if you're calculating heat you need to account for phase changes, but on the midterm things should be a little clearer.

Vincent Kim 2I

all variations of delta S = nRln(V2/V1), S = kBlnW, the gibb's free energy equation, delta S = qrev/T

these are just some I could think of right now, but there's probably more

Vincent Kim 2I

The derivations are just nice to know in order to understand the relationships of each term with another, but it's not necessary for the midterm.

Vincent Kim 2I

Just further developing on the previous reply, since delta S is q/T, the greater T is, the smaller delta S is. It's simply an inverse relationship

Vincent Kim 2I

It's also in the textbook on chapter 8, section 16 for a quick reference

Vincent Kim 2I

Essentially, it doesn't really matter whether it's kj or kj/mol, just use whatever you end up with as you work through the problem.

Vincent Kim 2I

It helps to work through all of the homework questions he assigns if you haven't done that already.

Vincent Kim 2I

Heat capacity isn't specific to a certain value and is fluid depending on the amount of substance there is. Specific heat capacity only refers to the amount of energy needed to raise the temperature of 1 gram of a substance by 1 C. No matter how much substance there is, the specific heat capacity wi...

Vincent Kim 2I

Resonance shouldn't necessarily affect bond enthalpy, as you can still use the values given to you to determine what you are looking for. For example a single bond between CO has bond enthalpy of 358 kj/mol, while a double bond between CO has bond enthalpy of 799 kj/mol. Either way, you're adding th...

Vincent Kim 2I

There can be much more than 2-4 reactions involved with the use of Hess's Law, but it's not necessary to use all of them because it's possible to represent the steps of a chemical reaction with fewer steps.

Vincent Kim 2I

Yes, the oxidation number of Hg would be (III) instead of (I), as the two Fluoride ions make the overall charge -2, which requires a +3 oxidation state from the Hg to make the compound +1.

Vincent Kim 2I

It's not that the equation flips from products becoming the reactants, but more that we are trying to calculate at which concentrations the reaction reaches equilibrium. If you just flip the equilibrium constant to 1/K, you're not changing anything about the concentrations.

Vincent Kim 2I

The equilibrium constant K only changes when the concentrations of the reactants and products are changed, not when their stoichiometric constants are.

Vincent Kim 2I

A simple Pt could be confusing to a reader, and it just makes it easier for everybody if you take the extra measure to write the oxidation number.

Vincent Kim 2I

Essentially if it doesn't matter which atom specifically needs the double bond in the lewis structure, then there is delocalization. For example, benzene, a 6 Carbon ring with three double bonds has delocalized pi bonds because there it doesn't matter which 3 Carbons are double bonded together, so l...

Vincent Kim 2I

Basically when the Q and K values in the problem are very close, then the changes in concentration (x) will be extremely small, even negligible in most cases.

Vincent Kim 2I

Also I believe any amphiprotic molecule is also amphoteric, but not any amphoteric molecule is amphiprotic.

Vincent Kim 2I

Resonance is just a term to describe when a molecule has a double bond that can be placed in multiple locations without changing the actual structure of the molecule. A molecule with resonance will always have the same formal charge, that doesn't change. Naturally, the real structure of the molecule...

Vincent Kim 2I

Also, a general rule of thumb:
Metals typically make ionic bonds with nonmetals, as their electronegativity difference is high
Nonmetals typically make covalent bonds with nonmetals, as their electronegativity difference is low

Vincent Kim 2I

I really doubt he expects us to memorize all values of electronegativity, so they'll probably be given to us.

Vincent Kim 2I

Typically we look at the principal quantum number to determine which orbital is lower in energy, but in the case of 3d and 4s, 4s is lower.

Vincent Kim 2I

You know whether a molecule uses a double or triple bond if you use all the available electrons in the covalent bond. For example, Carbonate (CO 3 2- ) has 24 valence electrons in total (4 from Carbon, 18 from three Oxygens, 2 from the 2- charge). The Carbon atom needs to double bond to one of the O...

Vincent Kim 2I

You start filling the 3d orbital after 4s because the 4s orbital generally has lower energy than the 3d orbital.

Vincent Kim 2I

The value of l is also not just (n-1), but can also include the negatives numbers too. For s: l can only be 0, while for p: l can be -1, 0, and 1.

Vincent Kim 2I

You don't necessarily have to think of the p-orbital as XYZ, it's just a label for each of the three orbital subsets. You can simply call them subset 1, subset 2, and subset 3 if you want. It's the same as you learned in high school.

Vincent Kim 2I

The energy levels don't have to have a specific interval of change. The Balmer series just refers to whenever electrons transition to the principal quantum number 2. It can be from both n=3 to n=2 and n=4 to n=2.

Vincent Kim 2I

I'm pretty sure ultraviolet light is typically used for photoelectric experiments.

Vincent Kim 2I

You're right to be using the work function, but the units are wrong. The question asks for how much energy is required to remove an electron from one sodium atom.

This means that you need to divide 1.506 x 10^5 J.mol-1 by avogadro's number (6.022 x 10^23).

It should give you 2.501 x 10^-19 J.

Vincent Kim 2I

Is it the number of photons or the energy of the photons that causes electrons to be ejected from the metal?

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