CHEMISTRY COMMUNITY

Julia Lung 1I

It's usually acidic unless otherwise stated

Julia Lung 1I

I would tell another chemistry joke
...but all the good ones Argon.

Julia Lung 1I

Why does hamburger have less energy than steak?

It's the ground state.

Julia Lung 1I

In what situation would we use the rate of formation or the unique rate law? How will we be able to tell?

Julia Lung 1I

I heard from my TA that sig figs will be graded. Has anyone heard something similar or different?

Julia Lung 1I

What's the difference between chemistry jokes and physics jokes?

Chemistry jokes can be funny periodically, but physics jokes have more potential.

Julia Lung 1I

Why wouldn't you put H2O(l) into the cell diagram the it is given on the cathode side?

Julia Lung 1I

There are three equations that are given connecting Ecell, K and DeltaG if you're given one you can find the others.

Julia Lung 1I

The reason why you haven't seen it on the constants and equations sheet is because we didn't need it for the two test or the midterm, but it will be on the final. The final constants and equations sheet should be on the Chem 14B website.

Julia Lung 1I

What kind of fish is made out of 2 sodium atoms?

2Na

Julia Lung 1I

Will we have to be able to derive the rate laws for the final or just understand what is going on and how to use it?

Julia Lung 1I

average rate is when you take the change over time while instantaneous is usually when time is approaching zero and you take the derivative

Julia Lung 1I

Tests are given back in your discussion section

Julia Lung 1I

In a galvanic cell diagram, I know we put a line between the solids and the aqueous solution and a comma between different aqueous molecules in the same beaker, but would we use a comma or a line to separate gas and aqueous in the same beaker?

Julia Lung 1I

The problem asks you to balance the reaction using redox half rxns: O3 + Br- ----> O2 + BrO3-
For this problem O3 is oxidized = 0 to O2 which is -2, I thought O2 is suppose to equal 0 can anyone explain why and in what situations O2 would equal 0 or -2?

Julia Lung 1I

What part of Gibbs Free Energy should we know for the second test?

Julia Lung 1I

Calculate the change in entropy when the pressure of 1.50 mol Ne(g) is decreased isothermally from 15.0 atm to 0.500 atm. Assume ideal behavior. I got the right answer for this problem using ΔS=nRln(P1/P2) = ΔS=(1mol)(8.314 J/k*mol)ln(15.0atm/0.500atm) = 42.2J/K but I'm confused how the units cancel...

Julia Lung 1I

The solution only calculated the C-C bonds so there would be 3 mol of the CC triple bond broken and 6 mol of the C-C formed from the benzene ring.

Julia Lung 1I

Usually the problem gives you values or tells you what method to use to solve for the enthalpy

Julia Lung 1I

Standard Enthalpy of Formation (deltaH) is the most stable form of a molecule. You would use: ΔH(of formation) = Sum of ΔH(of formation of products) - ΔH(of formation of reactants). This is the 3rd method to find enthalpy changes from last weeks lecture.

Julia Lung 1I

What chapter is this week's homework suppose to be on? Do we continue with chapter 8?

Julia Lung 1I

Usually the problems specify whether to find the concentration or partial pressure, you can use Kc to also find the K of gases but I think they want us to use Kp for gases

Julia Lung 1I

They can both be used to find delta U depending on what's given in the problem. We also went over that when there is no volume change (in most of biology) then delta U = delta H.

Julia Lung 1I

Do we only do problems on thermochemistry chapter 8?

Julia Lung 1I

Yes, use sig figs at the end when you add the enthalpies. I don't think they're that strict on it though.

Julia Lung 1I

There's also an equation that goes from Kc to Kp
Kp=Kc(RT)^delta(n) or Kp=(T/12.03)^delta(n)*Kc

Julia Lung 1I

I'm confused on how to select the correct Ka and Kb value from the table given in the textbook when they are not exactly what's in the problem. For example, in 12.71 to calculate the pH of 0.63M of NaCH3CO2(aq) would I just use the Ka value for acetic acid CH3COOH (1.8x10^-5)?

Julia Lung 1I

X represents the change in concentration, it can either be positive or negative whether it is increasing or decreasing.

Julia Lung 1I

You would use the initial concentration mostly for the ICE table

Julia Lung 1I

What is the significance of using bar for units and what would be the easiest approach for problems like 11.79 6th edition? 11.79 A reactor for the production of ammonia by the Haber process is found to be at equilibrium with PN2 3.11 bar, PH2 1.64 bar, and PNH3 23.72 bar. If the partial press...

CHEMISTRY COMMUNITY

Search found 30 matches

Re: How to tell if its in acidic or basic

Re: Post All Chemistry Jokes Here

Re: Post All Chemistry Jokes Here

Unique rate law

Sig Figs

Re: Post All Chemistry Jokes Here

Test #2 4b

Re: Formulas

Re: Equations

Re: Post All Chemistry Jokes Here

Deriving Rate Laws

Re: Instantaneous vs Average

Re: Test #2

Galvanic Cell Diagram [ENDORSED]

6th edition 14.5a

Test 2

6th edition 9.11

Re: 8.73 Help (Bond Enthalpy)

Re: Hess's Law

Re: Standard formation deltaH

Week 5 Homework

Re: Test Question

Re: U:Internal Energy

Homework #3

Re: Sig Figs with Enthalpy

Re: converting between kp and kc

Ka and Kb values

Re: ICE

Re: Equilibria Changes

Homework 11.79 6th edition