## Search found 16 matches

Sat Mar 09, 2019 8:11 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 6th edition, 14.55
Replies: 2
Views: 187

### Re: 6th edition, 14.55

So we can assume that Ni is going to be formed at the cathode because that is the only substance that would form a solid via electrolysis in this reaction. However, the book uses the oxidation of water at the anode because it has a more negative standard E potential than the SO4- standard potential....
Sat Mar 09, 2019 7:37 pm
Forum: General Rate Laws
Topic: Reaction Orders for multiple reactants
Replies: 1
Views: 89

### Reaction Orders for multiple reactants

How do we determine the order of a reaction with a given rate law for multiple reactants? ex. is the order of Rate = k[A][B] first order because both are to the first power or second order because there are two of the reactants?
Sat Mar 09, 2019 7:31 pm
Forum: First Order Reactions
Topic: Second and Zero Order Units
Replies: 2
Views: 151

### Re: Second and Zero Order Units

Zero and second order k values have different units because of their relationship to the rate which is always mol/L/sec. So because rate = k for 0 order then the units are simply mol/l/s while Rate = k[A]^2 for a second order equation so the units for k will be L/mol/s to cancel out the mol^2/L^2 of...
Fri Feb 22, 2019 11:56 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Gibbs and Work
Replies: 1
Views: 79

### Re: Gibbs and Work

Yes Delta G = -nFE because Delta G = We where We is the maximum non expansion work of the system.
Fri Feb 22, 2019 11:43 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Problem 11.111-Sixth Edition
Replies: 1
Views: 123

### Re: Problem 11.111-Sixth Edition

So from the problem we can see that K1 = 10*K2. We use the equation Delta Gr = -RT lnK (i will now refer to Delta Gr as G1 or G2 for convenience purposes), so K = e^-(G/RT). K1 = 10*K2 = e^-(G1/RT) and K2 = e^-(G2/RT). From here you can divide the first equation (K1) by the second equation (K2) to i...
Fri Feb 22, 2019 11:35 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneity
Replies: 6
Views: 280

### Re: Spontaneity

Gibbs free energy is the measurement of the maximum reversible work that can be done by a system so a negative GFE change means the system performs work or loses that energy to the surroundings which makes it spontaneous. If the GFE is positive then the forward reaction will not be spontaneous becau...
Sun Feb 10, 2019 12:13 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.89 6th edition
Replies: 1
Views: 116

### 11.89 6th edition

In part b why are all of the partial pressure values for Kp divided by 100? Is this an approximation of the standard pressure in kPa?
Sat Feb 02, 2019 5:44 pm
Forum: Phase Changes & Related Calculations
Topic: State functions and Energy
Replies: 3
Views: 226

### Re: State functions and Energy

Probably not. I haven't seen any questions asking that in discussion or the homework.
Sat Feb 02, 2019 5:39 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: bond enthalpy equations
Replies: 6
Views: 245

### Re: bond enthalpy equations

If by solving bond enthalpy equations you mean using bond enthalpies to find the enthalpy of a reaction then you want to first find out which bonds are being broken and which are being formed. Then you sum the enthalpies of the breaking bonds and the forming bonds separately. Then you subtract the s...
Sat Feb 02, 2019 5:22 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: calorimeters
Replies: 7
Views: 260

### Re: calorimeters

I think all the other information necessary for the problem will be given in the question.
Sun Jan 20, 2019 11:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Polyprotic Acids and Bases 12.79
Replies: 2
Views: 189

### Re: Polyprotic Acids and Bases 12.79

For the first set of calculations you simply do the strong acid reaction of H2SO4(aq). This will fully dissociate because it is a strong acid. Find your concentration of H2O+ and HSO4- for this first section. For the second set of calculations, you will need to set up an ice table with HSO4-,SO4-2, ...
Sun Jan 20, 2019 10:25 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5% rule
Replies: 12
Views: 486

### Re: 5% rule

If the error of your approximation is less than 5% then using the approximation is fine. So you find your x value through the approximation method then divide by your initial amount of weak acid or base and multiply by 100. If the number calculated is greater than 5 then the quadratic formula should...
Sun Jan 20, 2019 10:12 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Week 1 Lecture 3
Replies: 4
Views: 190

### Re: Week 1 Lecture 3

Remember that when you compare the values of Q and K it tells you the direction the reaction will proceed in order to achieve equilibrium. So when we calculated the Q value as 25 this tells us that there is a higher proportion of reactants to products than K because Q has a smaller value which means...
Sun Jan 13, 2019 2:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between Kc, Kp, and K
Replies: 2
Views: 143

### Re: Difference between Kc, Kp, and K

Kc is just the equilibrium constant using the concentrations of the reaction components and can be applied to aqueous solutions and gases, solids and pure liquids are not included in the K calculation. Kp uses the partial pressures and is only applied to gases. K is just a general term for the equil...
Sun Jan 13, 2019 2:14 pm
Forum: Ideal Gases
Topic: How much of Ch.5 are we expected to know?
Replies: 3
Views: 148

### Re: How much of Ch.5 are we expected to know?

If you are referring to chapter 5 of the 6th edition then you should probably have an understanding of the units of pressure and gas laws sections of the chapter since we are using those ideas already. The molecular motion and real gases may come into play later in the class when we cover reaction k...
Sun Jan 13, 2019 2:04 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changes in Partial Pressure
Replies: 5
Views: 197

### Re: Changes in Partial Pressure

Temperature can be assumed to stay constant in a changing pressure but the question should state specifically whether or not the volume has changed or the pressure has changed from an inert gas because that affects the Q value when comparing to K.

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