CHEMISTRY COMMUNITY

Natalie Rotstein 3J

How do we know that the permanganate becomes a manganese ion and doesn't just lose electrons to the iron?

Natalie Rotstein 3J

The main types of reactions (I'm assuming you're referring to the electrophilic/nucleophilic rxns), are: -electrophilic addition, where an electrophile is added to another molecule. -bimolecular nucleophilic substitution (Sn2) in which one nucleophile replaces another nucleophile. This often looks l...

Natalie Rotstein 3J

For the 2013 final, on question 3, were the cell potentials of the half reactions given, or are they supposed to be determined somehow? On the answer key it looks as if the cell potentials are a part of the answer to part A, but how would that be found?

Natalie Rotstein 3J

Thank you for clarifying, I was mainly confused about whether we would need to know alkene structures/formulas from the name for alkenes other than the ones mentioned in lecture in the context of the electrophilic addition, such as ethene and 2-butene, but I think I understand what we need to know n...

Natalie Rotstein 3J

Generally alphabetical order is just for the ordering of the name, not the numbering, but I think it might be good form to start with the 1 with the first named substitutent in the previously described situation where every single carbon had a substitutent attached.

Natalie Rotstein 3J

ΔG double dagger can be between intermediate and transition or reactant and transition. It is usually shown as reactant to transition though. I think the difference isn't where in the graph it is measured but more just the context - they seem to be equivalent if you look at the equations to calculat...

Natalie Rotstein 3J

The quiz 3 prep includes alkenes and cycloalkenes, and Lavelle's responses to questions on the quiz prep problems seem to imply that we are expected to know how to solve all of the problems in the quiz prep, but the beginning of the thread it says alkanes and cycloalkanes in the textbook and only up...

Natalie Rotstein 3J

It's positive for the thing being considered; for the equation you mentioned, the reason one side is negative is because the concentration of the reactants decreases while the concentration of the products increases, making the change in reactants negative and products positive. To counter this so t...

Natalie Rotstein 3J

If a step is "very very slow," and that is the slowest specification for the rate of any step, it is the rate determining step. Because that step determines rate, a faster step prior to it would not affect the rate of the reaction, and therefore would not be included in the rate expression.

Natalie Rotstein 3J

In the textbook, it is said that "the rate law for a reaction is determined experimentally and cannot in general be inferred from the chemical equation for the reaction." I think that in general, the order might look like it can be "found" with the coefficients, but in reality th...

Natalie Rotstein 3J

For 0 order reactions, t1/2=[A]0/2k, which means t1/2 is proportional to A, which corresponds to a linear graph. For second order, however, t1/2=1/(k[A]0), which means t1/2 is proportional to 1/A - the graph of 1/x is not linear, so therefore the second order half life graph would also be nonlinear

Natalie Rotstein 3J

I was working on problem 9.13, and I initially was going to use the equations ∆S=nRln(T2/T1) and ∆S=nRln(V2/V1), because they seemed appropriate, but I ended up stuck because they did not give the number of moles, and I didn't see any way to calculate it. I then went to the answer manual to figure o...

Natalie Rotstein 3J

I was wondering this as well, and also, if which metal ions form water complexes and how they do it is something we would need to know for the final or if that information would be given to us if there was a question about it?

Natalie Rotstein 3J

All of the other ones have 10 electrons combined after the [kr] configuration - those electrons could theoretically leave the 5s shell and go to fill the 4d shell instead (that's how Pd can be 4d10). In+, however, has a combined total of 12 electrons after the [kr] configuration, so the configuratio...

Natalie Rotstein 3J

IF5 is polar because of the electron pair on the central atom. Because of this pair, the electron geometry would be octahedral. If you think of the electronegativity of each atom as a sort of "pull," there is one Fluorine that has an electron pair opposite it in the molecules structure, in...

Natalie Rotstein 3J

To get percent decomposition, you need to find the initial amount of the reactant, and then the final amount of the reactant. Then, subtract the final from the initial, and that is the amount that decomposed. Then, divide that number by the initial number, and that should give you the percent decomp...

Natalie Rotstein 3J

The calculation of the equilibrium constant does exclude liquid and solid concentrations. Though Kc and Kp are both forms of the equilibrium constant, Kc is when calculating it from molarity (for aqueuous solitions and gases), while Kp is when calculating from partial pressure (generally used more f...

Natalie Rotstein 3J

I doubt we would need to when we can just do it the way you said. Generally, I think the % mass composition would be the information given if in a problem where we need to find the empirical formula as opposed to chemical formula, because empirical is just ratios of atoms as opposed to the actual nu...

Natalie Rotstein 3J

Thought this one was worth sharing

Natalie Rotstein 3J

I've found that Sparknotes actually has really helpful reviews of high school / AP chemistry topics; they aren't super detailed but if you mainly need just a refresher on what you learned previously, they're a good resource. I've used them in the past to review for AP exams for various subjects.

CHEMISTRY COMMUNITY

Search found 20 matches

Re: Help on problem 14.17

Re: The types of reactions

2013 Final #3

Re: Quiz 3 Winter 2017

Re: Naming Help

Re: Delta G Double Dagger 2 vs Ea2

Re: Quiz 3 Winter 2017

Re: Units of K

Re: Rate Determining Step

Re: Orders for Reactions

Re: 15.99

HW Problem 9.13 - Number of Moles

Re: 12.65 (e) and (f)

Re: Fall 2013 Q2C

Re: 2013 Final 4 C

Re: Percent Decomposition

Re: Equilibrium constant help

Re: Mass % Composition

Re: Post All Chemistry Jokes Here

Re: Rusty on High School Chem [ENDORSED]