CHEMISTRY COMMUNITY

Alexandra Carpenter 1G

What is the difference between a galvanic cell and a voltaic cell? Are both spontaneous and therefore have a positive standard E?

Alexandra Carpenter 1G

In the Winter 2011 Midterm, #2B, it states that a monatomic gas, A has a larger number of particles than B, a diatomic gas. Can someone explain why a monatomic gas has more particles?

Alexandra Carpenter 1G

Will we have to know organic chem to the extent of what is on the practice final?

Alexandra Carpenter 1G

It is coincidental that in the problem we did in class on mechanism, the slow step was the one that contained the intermediate molecule both times correct? In other words, having the intermediate in the rate does not make that step the slow step?

Alexandra Carpenter 1G

Just to be clear, if a mechanism has two steps, can the first one be the slow step and the second one be treated at equilibrium?

Alexandra Carpenter 1G

Why does the k of a reaction go down when the activation energy goes up?

Alexandra Carpenter 1G

There is a problem in a workbook that asks, "Consider the reaction, A + B --> C + D, with rate = k[A]^2. True or false, the time it takes [A] to decrease from 1.0 to 0.50 M is the same as the time it takes for [A] to decrease from 0.50 to 0.25 M.

Why is this false?

Alexandra Carpenter 1G

The question includes 3 reactant, where A is first order, B is second order, and C is zero order. Part b asks you to write the rate law for the reaction. The answer doesn't include the concentration of C, but if we did in an answer, would it be marked wrong?

Alexandra Carpenter 1G

What is the definition of the reaction mechanism?

Alexandra Carpenter 1G

Is there a way to determine n just given the reaction? Or would they have to tell us in the problem.

Alexandra Carpenter 1G

In the problem, the reaction is given as N2(g) --> 3 H2(g) + 2 NH3(g). The unique rate if reaction is half of the rate of reaction for NO2. When finding this, do we divide by the coefficient of the reactant only?

Alexandra Carpenter 1G

A worksheet asks, "Arrange the following species from greatest to least strength as an oxidizing agent: Li(s), Na(s), Ag(s), Fe^3+(aq).
How do we tell the difference, especially in transition metals?

Alexandra Carpenter 1G

In the case of adding Pt(s) to the end of a cell diagram, how do we know if the metals in the redox reaction are conductive?

Alexandra Carpenter 1G

The question asks "Determine the equilibrium constants for the following reactions: (a) Mn(s) Ti2 (aq) --> Mn2 (aq) Ti(s)
In this question, if lnK = -35 (2 sig figs), why is the K value only 1 sig fig (6 x 10^-16)?

Alexandra Carpenter 1G

In a half reaction, by just writing out the oxidation that occurs, it may not be balanced. Hydrogen ions are used to balance any excess hydrogens on the other side of the reaction, while adding water molecules does the same for balancing oxygens. So we don't know for sure from the beginning that any...

Alexandra Carpenter 1G

3/2R is used to calculate the heat capacity, Cv,m, of a gas that is at constant volume. 5/2R is used to calculate the heat capacity, Cp,m, of a gas at constant pressure.

Alexandra Carpenter 1G

Just making sure, there is homework due this week in discussion right?

Alexandra Carpenter 1G

The question states, "Write the half-reactions and the balanced equation for the cell reaction for each of the following galvanic cells". Do we have to calculate E for this question? I didn't think we did but the solution manual does it.

Alexandra Carpenter 1G

What is affected when a reaction takes place in a basic or acidic solution?

Alexandra Carpenter 1G

In class we learned that if something was oxidized, that means it lost an electron, causing the oxidation number to increase. In 14.3 part a, the equation reads as: Cl2 (g) + S2O32- (aq) → Cl- (aq) + SO42-
If the chlorine ion is going from an oxidation state of 0 to -1, why is it being oxidized?

Alexandra Carpenter 1G

Do we have to know about the explanation of Trouton's Law?

Alexandra Carpenter 1G

Is the basis of the Third Law of Thermodynamics that perfect crystals have an entropy of 0 as the temperature reaches 0K? Or is there more to it? Thank you!

Alexandra Carpenter 1G

In class, we went over a problem where we needed to calculate the temperature needed to make the reaction spontaneous. I understand that delta G needs to be negative for the reaction to be considered as such. We got 333K by setting the delta G to 0, but would that be the final answer? Or would the a...

Alexandra Carpenter 1G

In my notes, the definitions for entropy and degeneracy seem similar, so what is the difference between the two?

Alexandra Carpenter 1G

The question states, "A 50.0-g ice cube at 0.0 C is added to a glass containing 400.0 g of water at 45.0 C. What is the nal temperature of the system (see Tables 8.2 and 8.3)? Assume that no heat is lost to the surroundings." The heat of the ice cube is 1.67 x 10^4 J + (209 J/degrees C)(Tf...

Alexandra Carpenter 1G

Will the homework questions we turn in this week be from Chapter 9?

Alexandra Carpenter 1G

In this problem, we use the equation Qfusion = mCfusion. Where in the textbook does it discuss this formula or where does it come from? I can't seem to find it.

Alexandra Carpenter 1G

What do the equations Cv,m = 3/2R and Cp,m represent or calculate? And when would we use them?

Alexandra Carpenter 1G

Since there is no matter or energy transfer from an isolated system to its surroundings, there is no way to change the internal energy of an isolated system correct?

Alexandra Carpenter 1G

In my discussion, we went over a problem that asked this, "There is 4.51 g of NaOH in 100mL of H2O at 19.5 degrees C. NaOH dissolves and the temp of H2O rises to 31.7 degrees C. Determine the delta H of the NaOH solution. When we worked out the problem, we didn't use the 4.51 grams of NaOH in o...

Alexandra Carpenter 1G

In problem #9b for Chapter 8, "The internal energy of a system increased by 982 J when it absorbed 492 J of heat. (a) Was work done by or on the system? (b) How much work was done?", is there a specific reason the answer is in scientific notation, instead of just 490 J? Or is it just a pre...

Alexandra Carpenter 1G

In lecture today, we went over the heating curve of water. Why does the vaporization transition (40.7 kJ/mol) require much more energy than the melting transition (6.01 kJ/mol)?

CHEMISTRY COMMUNITY

Search found 32 matches

Galvanic vs. Voltaic

Monatomic vs. Diatomic

Organic Chemistry

Slow steps and intermediates

Slow Step

k and Ea

Second Order

15.17

Reaction Mechanism

Order of the Reaction [ENDORSED]

15.3/Unique Rate

Oxidizing and Reducing Agents

Conducting Metal

14.35

Re: 14.1 Question

Re: 3/2R vs. 5/2R

Homework

14.11 [ENDORSED]

Basic vs. Acidic

14.3

Trouton's Law

Third Law

Class Example

Entropy vs. Degeneracy [ENDORSED]

8.41

Homework Week 3

8.39

Heat Capacity of Gases

Energy Change in an Isolated System

Discussion Calorimetry Question

Notation

Energy and Phase Changes