CHEMISTRY COMMUNITY

Katelyn 2E

Can anyone explain/provide their work for this question? For further reference, it is the one where 2/3 of the question was taken out and the one that remained was "under constant volume." How would you figure out moles for this question, too?

Katelyn 2E

Hi, can anyone provide the correct answer for this question? Thank you!

Katelyn 2E

Hi!
For the electrochemistry test (which I took Wednesday in Dane's section), how do you tell what the value of n, the number of electrons exchanged is? And also what is the balanced equation for this question?
Thank you!

Katelyn 2E

This isn't a homework problem, but could someone help me understand this question please? Thank you! In the reaction 4 Fe2+(aq) + O2(g) + 4 H3O+(aq) --> 4 Fe3+(aq) + 6 H2O(l), when the Fe2+ concentration alone was doubled, the rate increased by a factor of 8; when both the Fe2+ and the O2 concentrat...

Katelyn 2E

Dr. Lavelle also summarizes information regarding unique rates in this thread below and, in general, it is a very informative thread:
viewtopic.php?f=145&t=28677

Katelyn 2E

I'm a little confused as to how [C] is independent of the rate, as stated in the solutions manual.

Katelyn 2E

I know that our test only covers 15.1-15.6 but can someone please clarify which class lectures/material that covers and which homework problems would fit that frame?

Katelyn 2E

Matthew Lee 3L wrote:On the syllabus, it says to omit this question from the homework.

I think Dr. Lavelle meant to omit Section 15.9 of the reading, not the actual homework question.

Katelyn 2E

keep in mind that the rate of reaction is equal to the change in concentration over the change in time. and as said above, concentration is always found in mols

Katelyn 2E

also regarding this question, is there a difference in how we should calculate rate of reaction and rate of formation?

Katelyn 2E

For part a and part d of 14.5, what is the oxidation state of O3 and P4? Thank you!

Katelyn 2E

These are also some general rules that are really helpful: The oxidation state of an individual atom is 0. The total oxidation state of all atoms in: a neutral species is 0 and in an ion is equal to the ion charge. Group 1 metals have an oxidation state of +1 and Group 2 an oxidation state of +2 The...

Katelyn 2E

what about for O3 like in 14.5 part a?

Katelyn 2E

In lecture, we learned that degeneracy, W, is the number of ways of achieving a given energy state. W would be equal to the (number of microstates) ^ (number of particles in the system). To relate it to entropy, you would use the Boltzmann formula: S = kb(lnW).

Katelyn 2E

I would recommend drawing out the Lewis structures as well. Sometimes, the electron geometry will align with the number of orientation (in example 9.8 in the book), but it does not in this problem. The best way to be sure is to draw them out.

Katelyn 2E

Can someone refresh my memory as to what Dr. Lavelle said in class today regarding units for enthalpy? My impression is that he said kJ and kJ/mol could be accepted interchangeably (when we were doing the Hess's Law question).

Katelyn 2E

to follow up, how do you know that W is 6?

Katelyn 2E

Adding on to what Ryan said, DeltaG at equilibrium means there's no net flow, or no tendency for the reaction to favor either direction.

Katelyn 2E

Thermal disorder is the disorder arising from the thermal motion of the molecules (heating); an increase in heating supplied/temperature leads to an increase in the disorder of a system because the supply of energy increases the thermal motion of the molecules. Positional disorder refers to the diso...

Katelyn 2E

Can someone explain the Clausius Inequality and its relevance to what we have been learning about thermodynamics? I found the book's explanation to be a bit confusing.

Katelyn 2E

will we be discussing these different types of systems each in detail or should we just know the general conceptual idea behind them such as is provided here? thank you!

Katelyn 2E

I think the most important difference about biodiesel fuel compared to regular fuel is that it is renewable (it can also be domestically produced and is cleaner); instead of being produced from fossil fuels, it can be manufactured from vegetable oils, animal fats, or recycled restaurant grease.

Katelyn 2E

In class, Dr. Lavelle avoided using the word "disorder" to describe entropy but the book consistently uses it. How would we define/what was Dr. Lavelle's definition of entropy without using "disorder"?

Katelyn 2E

Will we have to know the Cvm and Cpm values for the test?

Katelyn 2E

I was wondering if anyone who had Dr. Lavelle last quarter has any suggestions as to how study for conceptual problems for this chapter. Thank you!

Katelyn 2E

Intermolecular forces are the forces of attraction between molecules. Ranked from weakest to strongest, the IMFs we learned last quarter in Chem 14A are London dispersion forces, dipole-induced dipole, ion-induced dipole, dipole-dipole, hydrogen bonding, and ion-dipole. What you are referring to wit...

Katelyn 2E

Just to be clear, Dr. Lavelle said this wouldn't be on this week's test right?

Katelyn 2E

My TA said that sig figs aren't as big a deal this quarter because students end up focusing more on worrying about sig figs than they do about getting the actual concepts down/the problems right. But yes, answer is written in scientific notation just for the purpose of sig figs.

Katelyn 2E

For bond enthalpies, I was wondering how we know which bonds to exclude from our calculations. Is it just the ones that repeat in the reactants and the products?

Katelyn 2E

I found the sections under "Reaction Enthalpies," "Hess's Law," "Standard Enthalpies of Formation," and "Bond Formation" to align with what we have learned in class up to this point.

Katelyn 2E

A living plant is an open system. Just think about it in terms of photosynthesis where it takes carbon dioxide from its surroundings to produce oxygen; thus there's a constant exchange/flow of mass and energy between the plant and its surroundings.

Katelyn 2E

A standard state of a substance is its phase (the most stable one) at 1 atm and 25°C. Liquid is the standard state for mercury and bromine. Gas is the standard state for noble gases, halogens, fluorine, chlorine, hydrogen, nitrogen, and oxygen, while all other elements are solid in their standard st...

Katelyn 2E

In discussion, one of the examples for a closed system my TA used was a coolant in a refrigerator coil. Can someone explain how it functions in a manner that makes it a closed system?

Katelyn 2E

Anne 2L wrote:what did the ice cube say to his mom as he was melting

MOM ITS JUST A PHASE

Katelyn 2E

Can someone please explain to me why bond enthalpies (method 2) are always positive? Thank you!

CHEMISTRY COMMUNITY

Search found 35 matches

Midterm Question 6B

Midterm, Question 4B

Test 2 Question 8

15.16

Re: Unique rates

15.17

Kinetics Test

Re: 15.9

Re: Finding reaction rate [ENDORSED]

Re: Textbook Problems 15.3 and 15.5

Homework Question 14.5

Re: calculating oxidation states

Re: oxidation

Re: Degeneracy

Re: 9.25

Units for enthalpy

Re: 9.25

Re: DG = 0 [ENDORSED]

Re: Types of Disorders [ENDORSED]

Clausius Inequality

Re: Useful Summary of Thermodynamic Definitions

Re: biodiesel fuel [ENDORSED]

Entropy Definition [ENDORSED]

Re: Cv vs. Cp [ENDORSED]

Concepts for Chapter 8 [ENDORSED]

Re: Determining Enthalpy of Vaporization

Re: Reversible vs Isothermal

Re: Exercise 8.7

Bond Enthalpies

Re: Good hw questions to practice?

Re: living plant

Re: Standard States

Closed System

Re: Post All Chemistry Jokes Here

Bond Enthalpies