CHEMISTRY COMMUNITY

Kelsey Jug 1J

Homework problem 9.7 that wants us to find the entropy change of 1 mol of ideal gas with a temperature change under constant pressure and constant volume. For the final, would we need to know that constant pressure is (5/2)R and that constant volume is (3/2)R? Also, for that same problem, how can so...

Kelsey Jug 1J

Can functional groups share a carbon?

Kelsey Jug 1J

For the Homework from Ch 4, are we only suppose to do the odd-numbered problems? If we are also recommended to do the even-numbered problems, is there a way to access the solutions to those?

Kelsey Jug 1J

Is a rate law allowed to have an intermediate concentration? or do we always have to solve with K to find the substitute for the intermediate? (such an the pre-equilibrium example in the course reader)

Kelsey Jug 1J

For our quiz this week, will we be given the equations for zero, first, and second order reactions? Will we be given these equations, but with each just not identified as to which equation it is? or will we not be given any equations at all on our 'givens' note sheet?

Kelsey Jug 1J

When solving homework problems, are we only suppose to be finding rates in (mol)/(L*s) or are we allowed to also express it in (mmol)/(L*s) depending on the units given in the problem? More specifically, on a quiz or test, will we be marked off for using mmol instead of mol?

Kelsey Jug 1J

When is water included in the Galvanic Cell Diagram? There have been a few problems in the homework in which water is involved in the reaction, but not included in the call diagram. (problem 14.11d, problem 14.15b, problem 14.23 a and c)

Kelsey Jug 1J

Can anyone confirm that the solutions manual for 14.35 part b) is incorrect? The solutions wrote one of the half reactions as In^3+ (aq) + 2 e- ----> In^2+ (aq). The coefficient of the electron is obviously wrong as +3 - 2 does not equal +2. From my calculations considering n = 1, I obtained K = 1.0...

Kelsey Jug 1J

Very helpful! Thanks!

Kelsey Jug 1J

I understand that the anode is on the right side of the cell diagram, and that the cathode is on the left side of the cell diagram, but does the order of the molecules within the anode or cathode matter for the diagram?

Kelsey Jug 1J

The solution states that Ni^2+ (aq) + 2e ---> Ni (s) has E(anode) = -0.23 V. The solution proceeds to flip the reaction so that the reaction is Ni (s) ----> Ni^2+ (aq) + 2e but does not switch the sign of the E(anode) to +0.23V. Aren't we always suppose to change the sign of the voltage when we reve...

Kelsey Jug 1J

When writing balanced equations in order to calculate Gibbs free energy from the Gibbs free energy of formation of the products and reactants, how do we know whether to use full integers to balance equations or fractions. For example, on problem 9.59, 2 Fe3O4 (s) + O2 (g) ---> 3 Fe2O3 was balanced t...

Kelsey Jug 1J

9.51 asks, why are so many exothermic reactions spontaneous? the answer gives the equation deltaG = deltaH - TdeltaS and says that exothermic reactions tend to be spontaneous because the result in an increase in the entropy of the surroundings. My question is, does the deltaS in the equation represe...

Kelsey Jug 1J

Homework problem 9.27.
Which has great entropy, HBr(g) or HF(g). The answer is HBr, and the solutions says that it is because Br is more massive and contains more elementary particles than F. What elementary particles is it talking about?

Kelsey Jug 1J

My calculator will not compute ln(6^(6.02*10^23)) listed in the solution. It replies back with "overflow" anytime I enter this value. Will we have to worry about this for the quiz?

Kelsey Jug 1J

My questions pertains to Ch 9 Problem 13: During the test of an internal combustion engine, 3L or nitrogen gas at 18.5 degrees C was compressed suddenly (and irreversibly) to 0.5L by driving in a piston. In the process, the temperature of the gas increased to 28.1 degrees C. Assume ideal behavior. w...

Kelsey Jug 1J

What equation would we use when calculating entropy and enthalpy when pressure is changing?

Kelsey Jug 1J

Will we have to have the values of the enthalpy of vaporization or fusion or the specific heat capacities of different states of water memorized for the quiz or will they be given?

Kelsey Jug 1J

what is a good rule of thumb for knowing which value of R we should use? (technically same value but just in different units)

Kelsey Jug 1J

For our quiz or midterm, will we need to have memorized the equations for molar heat capacity at constant volume and also at constant pressure? As in the 3/2R, 5/2R, 3R etc.?

Kelsey Jug 1J

I'm having some trouble understanding homework problem 8.49. It asks for the change in internal energy for the reaction of 1 mol of OF2 (g). Why wouldn't the change in internal energy just be the delta H given? Why do we have to take the work (-PdeltaV) into account? What work is being done? Wouldn'...

Kelsey Jug 1J

For some clarification of the example in the course reader about enthalpies of bonds breaking (involving C-C, C-H, and C-Br bonds), is it correct that we have to account for the formation of the C-C single bond because the C=C breaks completely before it forms a single bond, rather than just jumping...

Kelsey Jug 1J

Were we suppose to receive a workbook for 14B from the course reader store?

Kelsey Jug 1J

When can we expect to receive our grades for the course? Thanks for a great quarter! :)

Kelsey Jug 1J

lovin all these chem jokes (click jump to post if you can't see the image)

Kelsey Jug 1J

How do we know that the formal charge of CH2 with one bond and one electron pair is -1?

Kelsey Jug 1J

When drawing CH2Cl2, how does one know to place the H molecules next to each other and Cl molecules next to each other, rather than drawing them across from each other so that the molecule is non polar?

Kelsey Jug 1J

How do you know when to write the Lewis structure like the one on the left versus the one on the right? (Attached picture)

Kelsey Jug 1J

For a molecule that has a seesaw shape because of one lone pair of electrons, wouldn't the bond angles be slightly less than 90 degrees and slightly less than 180 degrees because of the repulsion from the lone pair?

Kelsey Jug 1J

Homework question 4.9 asks for the shape of ICL3 and the ClICl bond angle.

ICL3 is T-shaped, and the solutions manual only lists the slightly less than 90 degree angle, but shouldn't we also note that there's a slightly less than 180 degree angle? Will we have to note both angles on the midterm?

Kelsey Jug 1J

The solutions manual for electron configuration problems does not seem take into account the exceptions to electron configuration orbital patterns (unless I'm mistaken).

Should we not take into account the exceptions on the quiz when writing electron configurations on the quiz?

Kelsey Jug 1J

I missed the first 15 min of class on Monday. Were there any announcements regarding the quiz or other important info that I missed?
Thanks!

Kelsey Jug 1J

What is the chemical formula for coffee?

CoFe2

Kelsey Jug 1J

Pre assessment question from the Heisenberg Uncertainty module: The hydrogen atom has a radius of approximately 0.05 nm. Assume that we know the position of an electron to an accuracy of 1 % of the hydrogen radius, calculate the uncertainty in the speed of the electron using the Heisenberg uncertain...

Kelsey Jug 1J

What did iodine say while spying on copper?
I see you.

Kelsey Jug 1J

anyone have a good resource for memorizing the names and charges of compounds?

Kelsey Jug 1J

Will we have quiz or test questions from the other fundamental sections not covered by Chem Refreshers or Audio Visual Topics (aka Fundamentals A B C D I J K), or should we just focus in on the fundamentals that Dr. Lavelle emphasizes (E F G H L M)?

Kelsey Jug 1J

Do UAs have specific office hours or are they only available through email?

CHEMISTRY COMMUNITY

Search found 38 matches

Constant Volume and Constant Pressure

C and functional groups

Homework Ch4 Admin. Question

Rate Law and Intermediates

Quiz Equations

General Rate Question

H2O in Galvanic Cell Diagram

homework 14.35

Re: Cell Diagrams

Cell Diagrams

Homework 14.11

Writing Balanced Equations

Homework 9.51

Entropy from Mass

Homework Problem 9.25

Homework Problem 9.13

Changing Pressure

Memorize Values for Quiz?

The Value of R

Molar Heat Capacities

Problem 8.49

Bonding Enthalpies

Workbook

Chem Final [ENDORSED]

Re: Post All Chemistry Jokes Here

Homework 3.95

Homework 4.25 [ENDORSED]

Lewis structure and molecular shapes [ENDORSED]

Seesaw angles

ICL3 bond angles

Electron Configurations Exceptions?

Quiz Info

Re: Post All Chemistry Jokes Here

Pre Assessment Questions

Re: Post All Chemistry Jokes Here

Naming Compounds

Other Fundamentals

Undergraduate Assistants