CHEMISTRY COMMUNITY

Virpal Gill 1B

Because maybe there is more volume available to it. If it expanded isothermally, then the kinetic and potential energies of the molecules would still be the same, so the internal energy would remain the same. However, if the temperature changed during expansion, the internal energy would not remain ...

Virpal Gill 1B

When looking at entropy, the reaction is determined to be spontaneous if \Delta S total is greater than zero. (\Delta Stotal= \Delta S system+\Delta Ssurroundings) ) So even if the entropy of the system decreases, the reaction can still be spontaneous if the entropy of the surroundings incre...

Virpal Gill 1B

The greater the activation energy of each step, the slower the rate. So the curves with smaller hills/height (whatever you'd like to call them) have lower activation rates and are therefore faster (have greater rates).

Virpal Gill 1B

The problem states: "Use the information in Tables 8.3, 8.6, and 8.7 to estimate the enthalpy of formation of each of the following compounds in the liquid state. The standard enthalpy of sublimation of carbon is 717 kJ/mol. (a) H2O; (b) methanol, CH3OH; (c) benzene, C6H6 (without resonance); (...

Virpal Gill 1B

Will any organic chem be on the final since it was introduced in lecture?

Virpal Gill 1B

Labile: describes substances that do decompose or react rapidly Nonlabile/inert (same thing): describes substances that are thermodynamically unstable but do survive for long periods These are not as significant in relation to Gibbs Free Energy because these terms are more closely related to kinetic...

Virpal Gill 1B

If it is serving as a reactant in the first step and then being produced in the second step then it is a catalyst. On the other hand, an intermediate must first be formed by one of the steps and then used up in later steps.

Virpal Gill 1B

Can someone explain the effect of a catalyst on rate constants?

Virpal Gill 1B

If all other reactant concentrations remain the same and you change the concentration of the reactant of interest without changing the rate, then that reactant is zero order.

Virpal Gill 1B

If it is zero order the rate law is not dependent on the concentration of that reactant so it technically doesn't need to be included.

Virpal Gill 1B

We have gone over the correlating graph with each order so I think that's important to know.

Virpal Gill 1B

Does anybody know helpful videos to watch for chapter 15?

Virpal Gill 1B

Ammarah 2H wrote:I was stuck too and I keep getting 2649813.982. Is that what you’re getting as well?

Yeah I'm getting the same answer.

Virpal Gill 1B

I was having trouble understanding why the sign of the anode in an electrolytic cell is positive even though electrons are leaving the cell because reduction is taking place there. Does anyone else understand this concept?

Virpal Gill 1B

Does anyone know any helpful videos to watch to better understand chapter 14?

Virpal Gill 1B

14.1 was in an acidic solution while 14.2 was in a basic solution, so you have to know whether it is an acidic or basic solution when doing the problem.

Virpal Gill 1B

I am confused on the use of $\Delta G$ and $\Delta G^{\circ}$ . I know that when $\Delta G$ is negative the reaction is spontaneous, but does this also apply to $\Delta G^{\circ}$ ? What is $\Delta G^{\circ}$ used for?

Virpal Gill 1B

The question is: "Calculate the heat released by 5.025 g of Kr(g) at 0.400 atm as it cools from 97.6 C to 25.0 C at (a) constant pressure and (b) constant volume. Assume that krypton behaves as an ideal gas." The answer for constant pressure is -90.6 J and the answer for constant volume is...

Virpal Gill 1B

I know this is jumping ahead, but I was just wondering what chapters Test 2 would be on so I don't fall behind?

Virpal Gill 1B

Will Dr. Lavelle's Review Sessions on February 12th cover the same material in the 11 am session and the 1 pm session or are different questions covered in each review session?

Virpal Gill 1B

The problem states to calculate the equilibrium constant at 25 C and at 150 C. The solutions manual states that because the equilibrium constant is at 2 different temperatures we need to find the standard enthalpy of the reaction and the standard entropy of the reaction so the standard Gibbs free en...

Virpal Gill 1B

The question asks if the entropy of the process increases or decreases: SO 2 (g) + Br 2 (g) + 2 H 2 O(l) --> H 2 SO 4 (aq) + 2 HBr(aq). The solutions manual states that entropy should decrease as the total number of moles decreases. Do they mean the moles of gas or is it a rule that if the total mol...

Virpal Gill 1B

The problem states that the human body generated heat at the rate of about 100. W (1 W= 1 J/s). And the question asks at what rate does your body heat generate entropy in your surroundings, taken to be at 20. degrees Celsius? So would the entropy be that of the system or of the surroundings? The sol...

Virpal Gill 1B

Does anyone know any videos explaining the conceptual ideas of chapter 9? I'm having a harder time understanding this chapter than the last.

Virpal Gill 1B

Degeneracy is the number of ways of achieving a given energy state, while entropy is the probability that the system will be in a particular state.

Virpal Gill 1B

For our discussions this week, should we be turning in homework for chapter 8 or chapter 9? And if it's chapter 8, can we turn in problems from any part of the chapter since we have covered it all?

Virpal Gill 1B

Multiply the standard enthalpies of formation times the number of moles for the products and add them all together. Do the same for the reactants. Then, subtract the total of the products by the total of the reactants.

Virpal Gill 1B

Does anyone know how to do this problem using the enthalpy of sublimation instead of separately doing the enthalpy of fusion and enthalpy of vaporization?
The problem is: How much heat is required to convert a 42.30-g block of ice at 5.042 degrees C into water vapor at 150.35 degrees C?

Virpal Gill 1B

This question states to find the enthalpy of formation of CH 3 OH. I understand where the values for the bond enthalpies came from but in the solutions manual it states that the energy needed to "atomize 1 mol C(gr)" is 717 kJ/mol. Is this something we are meant to know? If so, how is that...

Virpal Gill 1B

A living plant is an open system because it needs to exchange mass and energy with its surroundings to stay alive.

Virpal Gill 1B

No the definition of standard states doesn't include temperature so a standard state can exist at any temperature.

Virpal Gill 1B

Dr. Lavelle mentioned that students find it easier to read a certain part of chapter 8 first during Monday's lecture. Does anyone know the page numbers for that section?

CHEMISTRY COMMUNITY

Search found 32 matches

Re: Gas Expansion

Re: Second Law application

Re: Reaction Graphs

8.67

Organic Chem on Final

Re: terms

Re: catalyst vs intermediate

Effect of catalyst on rate constants

Re: Identifying zero order

Re: zero order in rate laws

Re: Slopes

Chapter 15 related videos

Re: 14.47 a

Determining the signs of the electrodes in a Electrolytic Cell

Helpful Videos

Re: Add H+ or OH-

delta G vs. standard Gibbs free energy

8.31

Test 2

Dr. Lavelle's Review Sessions

11.83

9.33

9.1

Chapter 9 help

Re: Entropy vs. Degeneracy [ENDORSED]

Homework Turn In for Week 3

Re: Standard Enthalpies of Formation

Hw 8.87

Hw 8.67 part b

Re: living plant

Re: Standard Reaction Enthalpy Definition

Reading for Chapter 8