Search found 15 matches

by Carolyn Stephens 3H
Sat Mar 12, 2016 9:13 am
Forum: Administrative Questions and Class Announcements
Topic: Final Exam - snacks?
Replies: 3
Views: 888

Final Exam - snacks?

Is it appropriate and allowed to bring non-crunchy snacks to the final? Snacking sometimes helps me focus, especially for 3 hours
by Carolyn Stephens 3H
Fri Mar 11, 2016 12:11 am
Forum: Zero Order Reactions
Topic: Units [ENDORSED]
Replies: 7
Views: 1123

Re: Units [ENDORSED]

An easy way to determine the units of k is to understand that the rate needs to have units of M/s so for 0 order rate=k and therefore k=M/s. for 1st order: rate=k[A] where [A] has the units of M and so when multiplied with k, k must have units of s^-1. For second order rate=k[A]^2 where [A]^2 has un...
by Carolyn Stephens 3H
Fri Mar 11, 2016 12:06 am
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Cis and trans Vs. Z and E
Replies: 3
Views: 482

Re: Cis and trans Vs. Z and E

cis/trans and z/e are interchangeable in concept regarding which side of the double bond each molecules rests on. However, they are not completely interchangeable in naming. It is important to note that cis/trans can ONLY be used when you are comparing 2 carbons and 2 hydrogens attached to the doubl...
by Carolyn Stephens 3H
Sun Mar 06, 2016 10:31 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Keq for Conformations
Replies: 1
Views: 411

Re: Keq for Conformations

1 Gauche is from the ratio of Anti-confirmation to Gauche for every 4.6 molecules with the anti-confirmation, there is one with the Gauche confirmation.
by Carolyn Stephens 3H
Sun Mar 06, 2016 10:28 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8017
Views: 1402159

Re: Chemistry Jokes

Chemistry life advice:

success is a state function. It doesn't matter what path you take.
by Carolyn Stephens 3H
Sun Mar 06, 2016 10:25 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Torsional Strain
Replies: 2
Views: 334

Re: Torsional Strain

Torsional strain causes higher energy between the atoms of a molecule and results in organic molecules preferring an eclipsed conformation. hope that helps!
by Carolyn Stephens 3H
Wed Jan 27, 2016 6:43 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Quiz 1 Preparation Winter 2015 #3
Replies: 4
Views: 748

Re: Quiz 1 Preparation Winter 2015 #3

I understand the concept of work being negative because it expands and so therefore does work on the surrounding. However, I do not understand why deltaU equals 0 and q=-w. If the reaction is isothermal, then why wouldn't q=0 because q is the energy entering the system as heat. Also, if the reaction...
by Carolyn Stephens 3H
Tue Jan 12, 2016 11:05 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 8.25 Constant volume calorimeter
Replies: 1
Views: 767

8.25 Constant volume calorimeter

For question 8.25: "A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in .200 L of solution in the calorimeter (q=-3.50 kJ), resulting in a temperature rise of 7.32 C. In a subsequent experiment, 100.0 mL of .200 M HBr (aq) and 100.0 mL of ...
by Carolyn Stephens 3H
Tue Jan 12, 2016 9:51 pm
Forum: Phase Changes & Related Calculations
Topic: Molar Heat Capacity for Gases
Replies: 2
Views: 405

Re: Molar Heat Capacity for Gases

One molar heat capacity is for gas at a constant volume, while the other is for gas at a constant pressure. If the pressure remains constant, then the volume must increase as air is pushed out of the container. While if the volume is constant, then pressure must increase. We need 2 different values ...
by Carolyn Stephens 3H
Sat Jan 09, 2016 4:15 pm
Forum: Phase Changes & Related Calculations
Topic: Temperature of Phase Transition
Replies: 2
Views: 305

Re: Temperature of Phase Transition

Heat is defined as the total energy of the molecular motion within an object, whereas temperature is the average heat or thermal energy within an object. Temperature will increase with heat if the object is not undergoing a phase change. However, during a phase change the temperature will remain con...
by Carolyn Stephens 3H
Sat Nov 28, 2015 10:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Video: Equilibrium Concentration Fall 2012 Q6A
Replies: 3
Views: 534

Re: Video: Equilibrium Concentration Fall 2012 Q6A: mov

Question: A vial of SO2 (0.522 M) and O2 (0.633 M) react and reach equilibrium. Calculate the equilibrium concentrations of the products and reactants given that KC=5.66 x 10^-10 for this reaction: 2SO2(g)+ O2(g) --> 2SO3(g) Here is the same video answering that question in an effort to be more comp...
by Carolyn Stephens 3H
Mon Nov 23, 2015 10:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Video: Equilibrium Concentration Fall 2012 6a
Replies: 1
Views: 239

Video: Equilibrium Concentration Fall 2012 6a

A video by Katherine Jabba(3I), Erik Whitney (3G), and Carolyn Stephens (3H) explaining an equilibrium concentration problem (#6A) from the Fall 2012 Final Exam. We hope you find this entertaining and informative! (: Question: A vial of SO2 (0.522 M) and O2 (0.633 M) react and reach equilibrium. Cal...
by Carolyn Stephens 3H
Wed Oct 28, 2015 9:42 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polar or Nonpolar Molecules [ENDORSED]
Replies: 2
Views: 479

Re: Polar or Nonpolar Molecules [ENDORSED]

A molecule is polar the dipole moments between each atom do not cancel each other out and thus create a net dipole moment for the entire molecule. I was also having trouble understanding this and looked at the 10 minute video below and it helped a lot so I highly recommend it. https://www.khanacadem...
by Carolyn Stephens 3H
Tue Oct 13, 2015 5:04 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula of an unknown compound
Replies: 2
Views: 1347

Re: Empirical Formula of an unknown compound

To begin do not worry about a balanced equation because you are just looking for the empirical formula for one compound. Here is how I did it: 1. find the mass percentage composition for Co and F (339.20 gCo/996.08 g)x100 = 34.05% Co 996.08-339.20 = 656.88 g F (656.88/996.08)x100 = 65.95% F 2. use m...
by Carolyn Stephens 3H
Fri Oct 02, 2015 4:01 pm
Forum: Molarity, Solutions, Dilutions
Topic: Why amount of CH3CO2- doubled for each Ca(CH3CO2)2
Replies: 4
Views: 732

Re: Why amount of CH3CO2- doubled for each Ca(CH3CO2)2

If you think about the definition of a mole, one mole of Ca(CH3CO2)2 has 6.022x10^23 molecules, but each molecule has one mole of Ca and 2 moles of CH3CO2- (so, 2x6.022x10^23)and therefore every time you relate the 2 (Ca(CH3CO2)2 and CH3CO2-) you would need to double the amount of moles to make it c...

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