Search found 30 matches

by Jenna Salas 2H
Sat Mar 16, 2019 2:20 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: K
Replies: 1
Views: 32

K

When using K=k/k', does K represent the equilibrium constant or the overall reaction rate?
by Jenna Salas 2H
Sat Mar 16, 2019 2:18 pm
Forum: First Order Reactions
Topic: ln
Replies: 1
Views: 153

ln

When taking the natural log, does the answer retain the units of the value you took it from? For example, if you took ln[concentration] would your answer have the units of molarity?
by Jenna Salas 2H
Fri Mar 15, 2019 9:52 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Ideal Gas
Replies: 1
Views: 178

Ideal Gas

How do you know when to use Cp or Cv for ideal gases when you are using the deltaS=nCln(T2/T1)?
by Jenna Salas 2H
Sun Mar 10, 2019 5:31 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Approximation
Replies: 7
Views: 121

Re: Approximation

You can use approximation when the concentration you calculate is less five percent of the initial concentration.
by Jenna Salas 2H
Sun Mar 10, 2019 12:55 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate Determining Step
Replies: 2
Views: 62

Rate Determining Step

What would the overall reaction rate be if the first elementary step is not the slowest? Would you have to take into account the rate of the elementary steps before the rate determining step if it's not the first step?
by Jenna Salas 2H
Sun Mar 10, 2019 12:49 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: k' Value
Replies: 1
Views: 31

k' Value

How do you find k', and would its units be the same as the k value?
by Jenna Salas 2H
Sun Mar 03, 2019 2:00 pm
Forum: General Rate Laws
Topic: unique rate
Replies: 2
Views: 31

Re: unique rate

The unique rate takes into account the stoichiometric coefficients when finding the order of the reaction.
by Jenna Salas 2H
Sun Mar 03, 2019 9:44 am
Forum: Zero Order Reactions
Topic: Reaction Orders
Replies: 2
Views: 65

Reaction Orders

What do reaction orders mean? And what would be the difference between a first order and second order reaction?
by Jenna Salas 2H
Tue Feb 26, 2019 9:29 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: n
Replies: 8
Views: 133

n

In the equation deltaG=-nFE^0, what is n?
by Jenna Salas 2H
Sun Feb 24, 2019 3:21 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: salt bridge
Replies: 2
Views: 35

salt bridge

What is the purpose of a salt bridge?
by Jenna Salas 2H
Sun Feb 24, 2019 12:09 pm
Forum: Balancing Redox Reactions
Topic: Oxidizing and Reducing Agent
Replies: 3
Views: 68

Oxidizing and Reducing Agent

How do you determine what compound is the oxidizing or reducing agent in a reaction?
by Jenna Salas 2H
Sat Feb 23, 2019 3:00 pm
Forum: Administrative Questions and Class Announcements
Topic: What topics are going to be on Test 2?
Replies: 4
Views: 89

Re: What topics are going to be on Test 2?

Gibbs Free Energy and all the material of electrochemistry that we covered through Friday's lecture.
by Jenna Salas 2H
Sun Feb 17, 2019 3:32 pm
Forum: Van't Hoff Equation
Topic: Concept behind Van't Hoff Equation
Replies: 5
Views: 91

Re: Concept behind Van't Hoff Equation

We use the Van't Hoff to calculate K at different temperatures. This is important because K is dependent on temperature, so at different temperatures K has a different value.
by Jenna Salas 2H
Sun Feb 17, 2019 2:42 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 4J.13 Seventh Edition
Replies: 2
Views: 41

4J.13 Seventh Edition

How do you use deltaG to determine the stability of a compound?
by Jenna Salas 2H
Sun Feb 17, 2019 11:57 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous Reactions
Replies: 2
Views: 49

Spontaneous Reactions

What does it mean when a reaction is spontaneous? In other words, what is happening to the molecules of a spontaneous reaction? Does spontaneous mean that the reaction happens more quickly than normal?
by Jenna Salas 2H
Sun Feb 10, 2019 2:46 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: why is H negative when calculating S?
Replies: 4
Views: 82

Re: why is H negative when calculating S?

It's negative because you are going from a liquid to a solid. DeltaH of fusion is positive when you go from a solid to a liquid.
by Jenna Salas 2H
Sun Feb 10, 2019 2:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 1
Views: 30

Bond Enthalpies

When using bond enthalpies to calculate the reaction enthalpy, why do you subtract the sum of the products' bond enthalpies from the sum of the reactants' bond enthalpies instead of the other way around, like when you calculate the standard reaction enthalpy?
by Jenna Salas 2H
Sat Feb 09, 2019 6:15 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Difference in pathways
Replies: 1
Views: 40

Re: Difference in pathways

Reversible expansion occurs when the pressure is constantly changing, so you use the integral to find the area under the curve with the equation w=-nRTln(V2/V1). In irreversible expansion occurs when the external pressure is constant, so you don't need to use the integral, and the equation becomes w...
by Jenna Salas 2H
Sun Feb 03, 2019 5:26 pm
Forum: Calculating Work of Expansion
Topic: R constant
Replies: 3
Views: 43

R constant

How do I know which R constant when calculating any equation with R?
by Jenna Salas 2H
Sun Feb 03, 2019 2:08 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Expansion Work and Nonexpansion Work
Replies: 2
Views: 50

Re: Expansion Work and Nonexpansion Work

Expansion work deals with gases, and is calculated using -P*delta V. Non expansion work is any other work. I'm not sure how it relates to reversibility, but I hope this helps.
by Jenna Salas 2H
Sun Feb 03, 2019 10:58 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat (Csp)
Replies: 3
Views: 68

Re: Specific Heat (Csp)

If you're not given the specific heat capacity you can calculate it by dividing the heat capacity by the grams of the substance you have. Heat capacity is kJ/degrees Celsius.
by Jenna Salas 2H
Sun Jan 27, 2019 3:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 3 Methods to solve for Enthaply
Replies: 3
Views: 57

Re: 3 Methods to solve for Enthaply

Method 1 is Hess's Method. For this one you take the delta H of each reaction and add them to get the net delta H of the reaction. In method 2 you add the bond enthalpies to calculate the net delta H of the reaction. In method 3 you subtract the standard enthalpy of formation of the reactants from t...
by Jenna Salas 2H
Sun Jan 27, 2019 12:55 pm
Forum: Phase Changes & Related Calculations
Topic: Phase changes
Replies: 14
Views: 157

Phase changes

I know phase changes from liquid to vapor, solid to liquid, and solid to vapor are always endothermic. Would the opposite phases changes (vapor to liquid, and liquid to solid) always be exothermic?
by Jenna Salas 2H
Sun Jan 27, 2019 12:37 pm
Forum: Phase Changes & Related Calculations
Topic: Relationship between heat and work
Replies: 2
Views: 57

Relationship between heat and work

Can someone please explain the relationship between heat and work?
by Jenna Salas 2H
Sun Jan 20, 2019 12:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sig figs in pH
Replies: 7
Views: 59

Re: Sig figs in pH

When calculating pH, the whole number doesn't count as a sig fig only the decimal places do. For example, if your concentration of H3O+ has two sig figs, then your pH should have two decimal places.
by Jenna Salas 2H
Sun Jan 20, 2019 12:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Assuming X value
Replies: 3
Views: 51

Re: Assuming X value

The Ka or Kb should be less than 10^-3 in order to assume the value of x doesn't have to be used. However, you should always check to see if your approximation is okay. Your approximation is okay if it's less than 5% of the initial value.
by Jenna Salas 2H
Sun Jan 20, 2019 11:45 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6C.7 7th Edition
Replies: 1
Views: 28

6C.7 7th Edition

For the problem 6C.7, how do we compare the strength of acids if we're given the Ka for some and the Kb for others?
by Jenna Salas 2H
Sun Jan 13, 2019 3:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Question 5I.13 (7th Edition)
Replies: 1
Views: 38

Re: Question 5I.13 (7th Edition)

To find the answer compare the K values for the reactions Cl2->Cl and F2->F and which ever one is smaller is more stable.
by Jenna Salas 2H
Sat Jan 12, 2019 4:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE table calculation
Replies: 2
Views: 38

ICE table calculation

When you are setting up an ICE table what do you do with the pure solids and liquids, like H2O? Are they included in the calculations?
by Jenna Salas 2H
Sat Jan 12, 2019 4:31 pm
Forum: Ideal Gases
Topic: A bit of confusion
Replies: 3
Views: 78

Re: A bit of confusion

For PV=nRT, the value of R you use depends on the units. The 0.0821 value has the units L*atm*mol/K while the 8.314 value has the units J*mol/K. To determine what R value to use you would look at the units you have for pressure, temperature, and volume.

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