Search found 23 matches

by CosetteBackus_4F
Mon Feb 24, 2020 2:38 pm
Forum: Balancing Redox Reactions
Topic: half reaction
Replies: 10
Views: 89

Re: half reaction

Balance oxygen with water and balance hydrogen with H+ in acidic solutions.
by CosetteBackus_4F
Mon Feb 24, 2020 2:33 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Spontaneity
Replies: 8
Views: 63

Re: Spontaneity

Because Gibbs free energy and cell potential are inversely related, if the cell potential is positive, Gibbs free energy will be negative, therefore the reaction is spontaneous.
by CosetteBackus_4F
Mon Feb 24, 2020 2:27 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: work max
Replies: 2
Views: 35

Re: work max

The maximum work is equal to the change in Gibbs free energy (at constant T & P) which is equal to negative (moles of electrons transferred) x F(faraday = 96,485C*mol^-1) x E(max potential).
by CosetteBackus_4F
Mon Feb 24, 2020 2:20 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Electrode Potential
Replies: 4
Views: 37

Re: Electrode Potential

Typically you would assume it is given for the reduction potential unless otherwise stated.
by CosetteBackus_4F
Mon Feb 24, 2020 2:18 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: What does the nitrate do in a concentration cell?
Replies: 6
Views: 41

Re: What does the nitrate do in a concentration cell?

While the nitrate is not necessarily involved in the reaction itself, its purpose, like the salt bridge, is to allow ions to flow so that the charge can balance.
by CosetteBackus_4F
Tue Feb 11, 2020 4:58 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: 4F.1
Replies: 2
Views: 29

4F.1

Part C) Why would the entropy generated be less if you were in a room kept at 30. degrees Celsius?
by CosetteBackus_4F
Tue Feb 11, 2020 1:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test#1 Problem#6
Replies: 1
Views: 24

Test#1 Problem#6

What was the correct Ka value for this problem on the test?

The pH of a 0.010M solution of hydrofluoric acid is 2.63. What are Ka and percent ionization?
by CosetteBackus_4F
Tue Feb 11, 2020 1:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test#1 Problem#5
Replies: 1
Views: 23

Test#1 Problem#5

Can someone explain how to get the pOH of the solution after finding the Ka?

The pKb of fluoride is 10.8. A 0.12M solution of hydrogen fluoride was made for silicon wafer processing. What is the pOH of this solution at equilibrium?
HF(aq) + H2O(l) -> F-(aq) + H3O+(aq)
by CosetteBackus_4F
Tue Feb 11, 2020 1:25 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Test #1 Problem #2
Replies: 2
Views: 52

Test #1 Problem #2

Can anyone explain the correct way to reach the answer for problem 2 on test 1? Carbon monoxide is a toxic gas that irreversibly binds to hemoglobin. Determine which way the reaction will shift given the initial concentrations. CO(g) + H2O(g) -> CO2(g) + H2(g), Kc = 31.4 [CO] = 2.00M, [H2O] = 0.241M...
by CosetteBackus_4F
Mon Feb 10, 2020 8:57 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: equation conversions
Replies: 1
Views: 17

equation conversions

Can someone do a step-by-step breakdown of how to convert the equations for entropy between each other?
by CosetteBackus_4F
Tue Feb 04, 2020 1:12 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Differences between systems
Replies: 3
Views: 26

Re: Differences between systems

In a closed system, the energy of the system can be transferred to its surroundings. In an isolated system the energy of the system cannot be transferred to its surroundings (like insulated materials).
by CosetteBackus_4F
Tue Feb 04, 2020 1:06 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Energy of a system
Replies: 5
Views: 35

Re: Energy of a system

Delta H is the enthalpy of a reaction. It is calculated by the difference in the energy of the products and the reactants. If the reaction gives a net release of heat, it is exothermic and delta H is negative (heat is released into the surroundings). If the reaction requires heat, it is endothermic,...
by CosetteBackus_4F
Tue Feb 04, 2020 1:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: reversible v irreversible work
Replies: 3
Views: 28

Re: reversible v irreversible work

A reversible process is a system at equilibrium (where the internal pressure and external pressures are equal). An irreversible process is a system not at equilibrium (the pressure is constant as the volume changes).
by CosetteBackus_4F
Tue Feb 04, 2020 12:56 pm
Forum: Phase Changes & Related Calculations
Topic: about system and surroundings
Replies: 8
Views: 58

Re: about system and surroundings

A system is the object of interest whereas the surroundings are everything else. In this case the thermometer is an open system and the engine is a closed system.
by CosetteBackus_4F
Tue Feb 04, 2020 12:52 pm
Forum: Phase Changes & Related Calculations
Topic: phase changes, temperature constant?
Replies: 11
Views: 66

Re: phase changes, temperature constant?

Heat is necessary for the phase change to occur so the heat being supplied is being used to break the bonds and does not contribute to the heat of the substance itself.
by CosetteBackus_4F
Wed Jan 22, 2020 8:08 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 6D 15b
Replies: 2
Views: 12

Re: 6D 15b

You can find the Ka for Al^3+ as Al(H2O)6^3+ on page 478 in Table 6D.1. I think you just assume that AlCl3 dissociates in water.
by CosetteBackus_4F
Wed Jan 22, 2020 8:00 pm
Forum: Student Social/Study Group
Topic: midterm/final
Replies: 12
Views: 121

midterm/final

Are the midterm and final structured the same way as the tests?
by CosetteBackus_4F
Wed Jan 22, 2020 7:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework week 3
Replies: 1
Views: 17

Homework week 3

For the homework due week 3 can the problems be from chemical equilibrium and acids & bases or do they have to be on enthalpy?
by CosetteBackus_4F
Fri Jan 10, 2020 11:57 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Effect of Inert Gases
Replies: 9
Views: 50

Re: Effect of Inert Gases

Inert gases never have an effect on the equilibrium of a reaction because they do not react with the reactants or products.
by CosetteBackus_4F
Fri Jan 10, 2020 11:55 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and speed of reaction
Replies: 5
Views: 39

Re: Q and speed of reaction

Q measures the ratio of the concentrations of products and reactants, but is not affected by speed, only concentrations, temperature, and pressure.
by CosetteBackus_4F
Fri Jan 10, 2020 11:52 am
Forum: Ideal Gases
Topic: Adding reactions
Replies: 4
Views: 32

Re: Adding reactions

When adding reactions it is almost like you are adding all the reactants on one side of the equation and all of the products on the other. Therefore, when finding the equilibrium of the added reactions, you go through the same process as you would if it was just one reaction, where the concentration...
by CosetteBackus_4F
Fri Jan 10, 2020 11:40 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Value of K
Replies: 4
Views: 41

Re: Value of K

K is a ratio based on the concentrations or partial pressures of the products and reactants involved so its threshold is relative.
by CosetteBackus_4F
Fri Jan 10, 2020 11:36 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K for Heterogeneous Equilibria
Replies: 4
Views: 25

Re: K for Heterogeneous Equilibria

For heterogeneous substances, if there are aqueous reactants or products, it makes the most sense to use Kc, since Kp is just for gases.

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