CHEMISTRY COMMUNITY

Renee Delamater 2H

Why can't you trust atoms? They make everything up!!!!!!!

Renee Delamater 2H

I would also like to know the answer to this question

Renee Delamater 2H

I don't think there is a way to numerically calculate k' from k without knowing the K because K is always involved in the equation K=k/k'

Renee Delamater 2H

Enzymes are catalysts and their job is to lower the activation energy - the energy needed for the reaction to get between the products and reactants point.

Renee Delamater 2H

Even though there are only NO molecules in the problem, using 2 of the NOs makes it bimolecular.

Renee Delamater 2H

I agree - usually the enzyme or catalyst is used in the rxn to change its rate. It wold go above the equation or be given in the word problem.

Renee Delamater 2H

why would it be a less dramatic decrease?

Renee Delamater 2H

it would make sense here because there is only one mole of N2 and 3 moles of H2 - in order to make a full 1, you would need 3 times more N2 to balance our for the amount of H2

Renee Delamater 2H

Britney Alvey 1B wrote:For 0 order reactions, the units for k are are mol/(L*s). For 1st order reactions, the units of k are s^(-1). For 2nd order reactions, the units for k are L/(mol*s).

why are these the units? does it have to do with each graph for first order, zero order, and second order reactions?

Renee Delamater 2H

My TA said that if he asks us to derive on the exam, then it would be simple equations that we have gone over many times.

Renee Delamater 2H

I'm not sure about these either - also what is the difference between a solubility equilibrium, the Brønsted neutralization reaction, and the reaction in the nickel–cadmium cell??

Renee Delamater 2H

I would also be intersted in knowing the answer to this question - thanks!

Renee Delamater 2H

These statements are all right. OH is a negative charge, so you will use this with basic solutions while H3O is positive, so you will use this in acidic conditions. H2O is unlimited and you can always include this

Renee Delamater 2H

For this week's discussion, do we still have to hand in homework because the midterm is this week? I'm assuming we do but just checking!

Renee Delamater 2H

Last week, my TA said that we may need to know some but these would just be very simple equations we've gone over a lot of times during lecture.

Renee Delamater 2H

I would also like to know how to do this problem! Thanks!

Renee Delamater 2H

For constant pressure, you use 5/2R in the equation and for constant volume, you use 3/2R.

Renee Delamater 2H

Thanks!!!! :)

Renee Delamater 2H

For chapter 9 question 11 it asks the entropy change with a change in pressure and given moles. What is the equation we use for this? Thanks!

Renee Delamater 2H

These values are always given - we do not need to memorize them.

Renee Delamater 2H

The reason we put Delta G as 0 as well is because we didn't have that or T as givens for the equation: DeltaG= DeltaH-TDeltaS. We had H and S, but needed something for G in order to find T - when the reaction would be spontaneous. Putting it at 0 is a good first step and makes sense here because we ...

Renee Delamater 2H

Why do liquids have a higher heat capacity?

Renee Delamater 2H

How do you find the change in internal energy with only a reaction and delta H given? It says "What is the change in internal energy for the reaction of 1.00 mol OF2? in the reaction OF2(g) + H2O(g) = O2(g) + 2H(g)." How do you find this for only 1 mole of one of the reactants?

Renee Delamater 2H

How does this relate to Hess's Law? Does it have to do with how Hess's law is the sum of enthalpies?

Renee Delamater 2H

Content from this week won't be on the exam, right? I'm pretty sure it's just material from Weeks 1 and 2

Renee Delamater 2H

Thanks! So how does this equation and idea relate to specific heat? Is specific heat involved in the equation to find enthalpy because it is needed in each step of a specific reaction?

Renee Delamater 2H

I agree; technically the energy is released so it makes sense that it would be a negative number (because exothermic reactions are negative) but since it is in relation to the outside receiving the energy, it is gaining a positive amount of energy.

Renee Delamater 2H

What exactly does Hess's Law state?

Renee Delamater 2H

The heat of fusion uses unit of mass (the specific heat of fusion), and the molar heat of fusion is the enthalpy change per amount of substance referred to in moles. Using the example of H2O, you first find the mass of ice melted with the volume of melt. Then you calculate the energy (in joules) rel...

Renee Delamater 2H

During the face changes, the part of the phase graph with a constant slope is when the phases are in the process of changing. For instance, the line between the slopes showing liquid water and ice is as the H20 is freezing into a solid.

Renee Delamater 2H

When the temperature is greater, there is more heat and therefore more energy. I think that this would cause enthalpy to also increase.

CHEMISTRY COMMUNITY

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Re: Post All Chemistry Jokes Here

Re: Catalysts

Re: K and K'

Re: Enzyme

Re: molecularity

Re: Catalyst

Re: Rate of consumption vs concentration

Re: Hw 15.1 [ENDORSED]

Re: units of K

Re: Derivation

Re: Help on 14.15 half-reactions

Re: When to include electrolyte in cell diagram

Re: Basic and Acidic conditions [ENDORSED]

Re: Practice Midterm [ENDORSED]

Re: Derivation of Formulas

Re: Practice Problem

Re: Textbook 9.7

Re: 9.11

9.11

Re: bond enthalpies

Re: Example in Lecture

Re: Heat Capacity

8.49

Re: Why is enthalpy a state function? Why is heat not a state function?

Re: Week 3 Test Topic is endorsed

Re: Hess's Law

Re: 8.51 energy "released"

Hess's Law

Re: Equations

Re: Phase Changes: Molecular Level [ENDORSED]

Re: Enthalpy and Temperature [ENDORSED]