## Search found 28 matches

Sat Mar 14, 2020 11:14 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: HW 7.1 Kinetic control vs Thermodynamic control
Replies: 2
Views: 96

### Re: HW 7.1 Kinetic control vs Thermodynamic control

Yes. At a lower temperature, kinetics is the main control. At a higher temperature, thermodynamics is the main control.
Sat Mar 14, 2020 11:09 am
Forum: Calculating Work of Expansion
Topic: Increase/Decrease
Replies: 6
Views: 117

### Re: Increase/Decrease

If the expansion is against 0 pressure, then there would not be a change in work.
Sat Mar 14, 2020 11:07 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: largeness of species and molar entropy
Replies: 3
Views: 106

### Re: largeness of species and molar entropy

There is more disorder in the arrangement of the atoms and more disorder in the positions of the electrons.
Sat Mar 14, 2020 11:06 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: test problem 4A.5 continued
Replies: 3
Views: 100

### Re: test problem 4A.5 continued

If you look back at the notes, you can see Dr. Lavelle derive the equation for the reversible expansion. Additionally, it is also in the book.
Sat Mar 14, 2020 11:05 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Bike Example for Closed System?
Replies: 2
Views: 149

### Re: Bike Example for Closed System?

Dr. Lavelle was saying you could add energy but increasing the pressure of the system by adding air to the bicycle tire.
Sat Mar 14, 2020 11:03 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Using kJ/mol vs. kJ
Replies: 2
Views: 106

### Re: Using kJ/mol vs. kJ

Additionally, if you evaluate the equation to solve for the variable, you can determine what units you need to use.
Sat Mar 14, 2020 11:01 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Chemical Equilibrium biological examples
Replies: 2
Views: 96

### Re: Chemical Equilibrium biological examples

I don't think we need to know certain ones but know how to apply the topics to biological examples. For example, the stomach acid one on the midterm is a biological example question.
Sat Mar 14, 2020 10:58 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5.57
Replies: 2
Views: 111

### Re: 5.57

The amount of SO3 is given and the value of K is given so you can use those two values to find the concentrations of NO.
Sun Mar 01, 2020 2:00 pm
Forum: Balancing Redox Reactions
Topic: 6.K5 b)
Replies: 1
Views: 33

### Re: 6.K5 b)

First, you balance Br2->BrO3 by adding a 2 in front of the BrO3 so the Br is balanced. Then, add 10 e- to the right side to balance the charge. Add 3 H2O to the left side to balance the oxygen and finally add 6H+ to the right side to balance the hydrogen. Then balance the half reaction of Br2->2Br- ...
Sun Mar 01, 2020 1:53 pm
Forum: Balancing Redox Reactions
Topic: 6N.1
Replies: 2
Views: 49

### Re: 6N.1

It must be a mistake in the solutions manual, because there is no reason why there would be an addition of 2 electrons.
Sat Feb 29, 2020 6:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram order
Replies: 4
Views: 65

### Cell diagram order

If the two ions in the cathode are both in aqueous solution, like Ce4+(aq) and Ce3+(aq), does the order in the cell diagram matter? For example, can it be Pt(s)|I-(aq)|I2(s)||Ce4+(aq),Ce3+(aq)|Pt(s) or Pt(s)|I-(aq)|I2(s)||Ce3+(aq),Ce4+(aq)|Pt(s)?
Sat Feb 29, 2020 5:57 pm
Forum: Balancing Redox Reactions
Topic: 6L.3d
Replies: 1
Views: 43

### 6L.3d

In problem 6L.3d, how do you get the two half reaction for the cell diagram. I can't figure out how to get the answers in the solutions manual. The problem is

Pt(s)|O2(g)|H+(aq)||OH-(aq)|O2(g)|Pt(s)

and the solutions manual says

O2(g)+2H2O(l)+4e-->4OH-(aq)
O2(g)+4H+(aq)+4e-->2H2O(l)
Wed Feb 26, 2020 5:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6L.3b
Replies: 2
Views: 36

### 6L.3b

If there is Pt and C involved in the galvanic cell, are they included in the half reactions/balanced equation?

Example: C(gr)|H2(g)|H+(aq)||Cl-(aq)|Cl2(g)|Pt(s)
Wed Feb 26, 2020 5:12 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Gibbs free energy and 6L.1
Replies: 3
Views: 68

### Re: Gibbs free energy and 6L.1

I'm confused how they got 2 moles for part a. I know Ce is being reduced, but how is I being oxidized? The charges are the same?
Wed Feb 26, 2020 4:43 pm
Forum: Balancing Redox Reactions
Topic: 6K5A
Replies: 3
Views: 84

### Re: 6K5A

You have to first balance the oxygens in the equation O3->O2 by adding one water to the right side. Then, the balance the hydrogens, you have to add 2 H+ to the left side. In order to balance the charge then, you have to add 2 e- to the left side.
Wed Feb 26, 2020 4:38 pm
Forum: Balancing Redox Reactions
Topic: 6K.1
Replies: 2
Views: 63

### Re: 6K.1

For every 1 H2O you add, you have to add 2H+ to the other side. Additionally, make sure all of the other elements are balanced before you balance the oxygen and hydrogen!
Wed Feb 26, 2020 4:32 pm
Forum: Balancing Redox Reactions
Topic: Oxidizing agent and Reducing Agent
Replies: 4
Views: 80

### Re: Oxidizing agent and Reducing Agent

A reducing agent loses electrons, so it is reducing the other agent. Conversely, the oxidizing agent is gaining electrons, so it is oxidizing the other agent since it is taking the electrons from the other agent.
Wed Feb 26, 2020 4:29 pm
Forum: Balancing Redox Reactions
Topic: Help on 6K.3 part d [ENDORSED]
Replies: 3
Views: 93

### Re: Help on 6K.3 part d[ENDORSED]

How do you know there is an error in the solutions manual?
Tue Feb 11, 2020 7:59 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal Reactions
Replies: 4
Views: 76

### Isothermal Reactions

Why is deltaU always 0 for an isothermal reaction?
Mon Feb 10, 2020 10:02 pm
Forum: Phase Changes & Related Calculations
Topic: 4.5
Replies: 1
Views: 31

### 4.5

In 1750, Joseph Black performed an experiment that eventually led to the discovery of enthalpies of fusion. He placed two samples of water, each of mass 150. g, at 0.00 8C (one ice and one liquid) in a room kept at a constant temperature of 5.00 8C. He then observed how long it took for each sample ...
Sat Feb 08, 2020 2:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4D.15
Replies: 1
Views: 26

### 4D.15

The answer to 4D.15 in the solutions manual matches the answer I got, but the solution is different. Can someone explain why the solutions manual uses the equations and where they got the equations from.
Sat Feb 08, 2020 12:55 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State of reactants
Replies: 1
Views: 23

### State of reactants

In the book, in section 4D.4, one of the examples has the state of carbon as C(gr). What state does gr represent?
Thu Jan 16, 2020 9:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Problem 5.35
Replies: 1
Views: 40

### Problem 5.35

This problem shows a graph of three elements, A, B, and C, at their initial partial pressures and then the partial pressures of each at equilibrium. In the solutions manual, when the equilibrium constant is calculated, the partial pressures are all divided by 100 in the equation. Why are the partial...
Thu Jan 09, 2020 4:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reactants and Products Affecting Equilibrium
Replies: 2
Views: 13

### Reactants and Products Affecting Equilibrium

How does adding more of a product or a reactant to a system in equilibrium affect the equilibrium.
Thu Jan 09, 2020 4:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc and Kp
Replies: 2
Views: 18

### Kc and Kp

How do you convert between Kc and Kp?
Thu Jan 09, 2020 4:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs K
Replies: 7
Views: 56

### Re: Q vs K

Q is used when the reaction is not at equilibrium and K is the ratio of products to reactant when the system is at equilibrium.
Thu Jan 09, 2020 4:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K and Q
Replies: 5
Views: 51

### Re: K and Q

Yes. If Q>K, then the reaction will create more reactants and if Q<K, the reaction will create more products.
Thu Jan 09, 2020 4:02 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: equilibrium and forming/decomposing
Replies: 2
Views: 22

### Re: equilibrium and forming/decomposing

It is not at equilibrium, because the pressures of each do not have to be equal to be at equilibrium, but rather the forward and reverse rates have to be equal. Since K is greater than 1, the reaction sits to the right, so more SO3 would form.