## Search found 28 matches

Sun Mar 10, 2019 10:39 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: rate determining
Replies: 3
Views: 112

### Re: rate determining

the slowest step is the rate determining step.
if the slowest step includes an intermediate then you'll have to substitute it with something else (there are examples on the textbook for this)
Sun Mar 10, 2019 9:08 pm
Forum: First Order Reactions
Topic: 7B.3 Part C help
Replies: 1
Views: 102

### Re: 7B.3 Part C help

you can do something similar to the ice table (without the e though, more like icf) 2A -> B + C, 0.153M 0 0 -2x +x +x 0.034M (even if it's not in equilibrium, the reactants and products still increase/decrease with the ratio of 2:1:1.) which means x = 0.034M and 2x = 0.068M and the final concentrati...
Sat Mar 09, 2019 6:05 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8037
Views: 1408902

### Re: Post All Chemistry Jokes Here

found this online.
Sat Mar 09, 2019 5:34 pm
Forum: Second Order Reactions
Topic: 7th Edition 7A.11 2nd Order RXN
Replies: 2
Views: 154

### Re: 7th Edition 7A.11 2nd Order RXN

for a reaction with rate k[A]^a[B]^b, the order is simply a+b.
which means k[H2][I2] and a general k[A]^2 are both second order.
Sat Mar 09, 2019 5:26 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: k & K
Replies: 18
Views: 800

### Re: k & K

isn't boltzmann's constant used to calculate entropy with the number of possible states of a molecule and the number of molecules?
rate constants and boltzmann are entirely different things.
Sat Mar 09, 2019 5:20 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6N 3c) converting torr
Replies: 1
Views: 78

### Re: 6N 3c) converting torr

because we're using an equilibrium constant expression that includes both concentration (of the HCl) and pressure.
Fri Mar 08, 2019 2:01 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8037
Views: 1408902

### Re: Post All Chemistry Jokes Here

What should you do if no one laughs at your chemistry jokes?
keep telling them until you get a reaction.

(ughhhhhhhhhhhh)
Fri Mar 08, 2019 1:58 pm
Forum: First Order Reactions
Topic: Order reactions
Replies: 4
Views: 184

### Re: Order reactions

you won't. unless you're given other info ([A] change and rate change or actual rate laws)
Thu Mar 07, 2019 3:27 pm
Forum: Van't Hoff Equation
Topic: test 2
Replies: 7
Views: 560

### Re: test 2

you've been given one K value (Kw=10^-14) at 25C, and with the vant hoff equation you can find the other K (we'll call it K2) at 10C. here's how you do it: 1.plug in the numbers to the vant hoff equation (the temperatures have to be changed to Kelvins): ln(K2/Kw) = -58kJ/R(1/283K - 1/298K) 2. becaus...
Thu Mar 07, 2019 3:10 pm
Forum: General Rate Laws
Topic: 7A.13
Replies: 3
Views: 189

### Re: 7A.13

as the concentration of A increases by x, the rate of the reaction increases by x^a.
a=the reaction order of A.
Tue Feb 26, 2019 9:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 7th edition 6L. 3(d)
Replies: 1
Views: 90

### Re: 7th edition 6L. 3(d)

water is part of (aq)s so we should use it whenever using only the contents of the cell diagrams doesn't work. for 6l3d, the anode has O2(g) and H+(aq) and H2O(l). the cathode has OH-(aq), O2(g) and H2O(l). the half reactions are- anode reaction : 2H2O -> O2 + 4H+ + 4e- cathode reaction : 4e- + O2 +...
Tue Feb 26, 2019 9:30 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6L.5 (d) half reactions
Replies: 3
Views: 140

### Re: 6L.5 (d) half reactions

i think for this problem you'll have to look at the standard reduction potentials page. the two possible reactions are Au+ + e- = Au （+1.69v） and Au3+ + 3e- = Au （+1.40v） from the reduction potentials we know that the first reaction is the cathode and the second one is the anode. so we invert the se...
Mon Feb 25, 2019 12:58 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Platinum in Cell Diagrams
Replies: 1
Views: 78

### Re: Platinum in Cell Diagrams

i think we're supposed to use Pt(s) for all reactions lacking a solid that conducts electricity. (Lavelle said during lecture that you can also use graphite, but i think we should just stick to using Pt(s) for now)
Mon Feb 25, 2019 11:34 am
Forum: Balancing Redox Reactions
Topic: determining charges
Replies: 1
Views: 87

### Re: determining charges

for example for the reaction Fe3+(aq) + Cu(s) = Cu2+(aq) + Fe2+(aq) the oxidation reaction is Cu(s) -> Cu2+(aq) we have a zero charge on the left and a positive 2 charge on the right side, so adding 2 negatively charged electrons would balance it out. in this case it would be Cu(s) -> Cu2+(aq) + 2e-...
Fri Feb 22, 2019 12:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6L.3 7th ed. Write the half reactions and balanced equation for the cell reaction.
Replies: 2
Views: 137

### Re: 6L.3 7th ed. Write the half reactions and balanced equation for the cell reaction.

you can find a bunch of reaction potentials for almost every reaction in appendix 2b. i guess for the problems in this chapter we'll have to make use of that all the time:)
Thu Feb 21, 2019 4:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic/Voltaic Cells
Replies: 4
Views: 215

### Re: Galvanic/Voltaic Cells

http://butane.chem.uiuc.edu/pshapley/genchem2/c6/1.html
i found this site that seems to explain the difference between galvanic/electrolytic cells pretty well.
(since we're learning galvanic cells for now and at least i was kinda confused about those two:)
Wed Feb 20, 2019 10:30 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Midterm Question
Replies: 8
Views: 255

### Re: Midterm Question

i think you're not supposed to use Cpm here because for the second part of the solution since it's at constant V. the constant given in the solutions also stated that 20.81 was the Cv,m of nitrogen gas, not Cp,m.
(i used 3/2*R to calculate the Cv,m and was given points as well.
Thu Feb 14, 2019 8:45 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8037
Views: 1408902

### Re: Post All Chemistry Jokes Here

iphone 6 has four friends.
iphone 6s, iphone 6p, iphone 6d, iphone 6f.
Thu Feb 14, 2019 6:12 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Expansion of a system
Replies: 8
Views: 507

### Re: Expansion of a system

you can think of expansion (as in when w is negative) as the system doing something. sometimes the problems would say "system undergoes expansion" but actually it's up to you to figure out whether it's w<0 or not.
Fri Feb 08, 2019 11:13 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: U= 3/2nRT
Replies: 2
Views: 186

### Re: U= 3/2nRT

the reaction will most likely not be isothermal.
(you can look at question 4C3)
Tue Feb 05, 2019 2:38 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8037
Views: 1408902

### Re: Post All Chemistry Jokes Here

a photon arrives at a hotel. "do you need to check in your luggage?", the receptionist asks.
"no," the photon replies, "i'm traveling light".
(not exactly chemistry but
Tue Feb 05, 2019 2:28 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8037
Views: 1408902

### Re: Post All Chemistry Jokes Here

a teacher asks three students if they can fill up an entire classroom with something. half an hour later, student A returns with a sack of flour, shuts the windows, and pours the flour all over the room. student B lights a candle and brings it into the room. student C sees this and runs. student C s...
Sun Feb 03, 2019 10:29 pm
Forum: Phase Changes & Related Calculations
Topic: Week 4 Discussion Notes & Worksheet (2E, 2I, 2K)
Replies: 3
Views: 323

### Re: Week 4 Discussion Notes & Worksheet (2E, 2I, 2K)

thanks Joyce!:)
Tue Jan 29, 2019 9:10 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8037
Views: 1408902

### Re: Post All Chemistry Jokes Here

nacl/naoh
the base is under assault.
Sat Jan 26, 2019 8:17 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8037
Views: 1408902

### Re: Post All Chemistry Jokes Here

four people meet at a tattoo store. im getting this one , the twenty year old points to a structural formula of dopamine. i wish to attain happiness. and im getting this , the forty year old points to a structural formula of diazepam. i wish to be free from stress and live in tranquility. the sixty ...
Sat Jan 26, 2019 8:03 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8037
Views: 1408902

### Re: Post All Chemistry Jokes Here

what do chemists call a benzene ring with iron atoms in place of carbon atoms?
a ferrous wheel (ugh
Tue Jan 22, 2019 9:55 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8037
Views: 1408902

### Re: Post All Chemistry Jokes Here

John: “Hey that ranger Argon guy, why is he wearing a crown?”

Me: “Because LOTR is a tale about Argon, his friend Boron and their adventures with Zinc, Iron, Aluminum and Mercury.”

(credit to moderngardening.tumblr.com; im sorry this is lame)
Tue Jan 22, 2019 9:50 pm
Forum: Ideal Gases
Topic: How much of Ch.5 are we expected to know?
Replies: 3
Views: 123

### Re: How much of Ch.5 are we expected to know?

It's probably a little late but I guess 5G-J (7th edition) according to the assigned homework problems... (and by the way, for chapter six i think there's quite a lot of material we're not expected to know:)