Search found 43 matches
- Sun Mar 15, 2020 7:58 am
- Forum: Van't Hoff Equation
- Topic: Chemistry analysis
- Replies: 1
- Views: 105
Chemistry analysis
What is a "chemistry" van't Hoff analysis to calculate ∆H°, ∆S° and ∆G°?
- Sun Mar 15, 2020 7:55 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: ∆U and ∆H
- Replies: 1
- Views: 92
∆U and ∆H
Why does when q = qP then ∆U = ∆H - P∆V?
- Sun Mar 15, 2020 7:51 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: pH of acids
- Replies: 13
- Views: 420
pH of acids
Why do solutions of weak acids have higher pH values than solutions of strong acids at the same concentration?
- Sun Mar 08, 2020 11:49 pm
- Forum: General Rate Laws
- Topic: Rate change and species relation
- Replies: 1
- Views: 39
Rate change and species relation
How do we show how the rate of change of one species in a reaction is related to that of another species? Are they in the same reaction?
- Sun Mar 08, 2020 11:47 pm
- Forum: General Rate Laws
- Topic: Elementary reactions
- Replies: 5
- Views: 61
Elementary reactions
For one of the learning outcomes, it says to write rate laws for elementary reactions. What is meant by elementary reactions?
- Sun Mar 08, 2020 11:44 pm
- Forum: General Rate Laws
- Topic: Integrated rate law
- Replies: 1
- Views: 51
Integrated rate law
How do we know when to use an integrated rate law or k[A]? What is the difference?
- Sun Mar 08, 2020 11:41 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Tangent
- Replies: 3
- Views: 74
Tangent
How do we show how the instantaneous rate is obtained by drawing a tangent to the graph of concentration versus time? Is there an equation or graph we need to know?
- Sun Mar 08, 2020 11:38 pm
- Forum: Zero Order Reactions
- Topic: Order reactions and rate
- Replies: 2
- Views: 39
Order reactions and rate
How can I tell the difference between order reactions? What is the difference between order reactions and rate reactions?
- Sun Mar 01, 2020 5:58 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electromotive force
- Replies: 2
- Views: 38
Electromotive force
What is the electromotive force and why does it represent the maximum potential difference?
- Sun Mar 01, 2020 5:51 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrochemical Series
- Replies: 3
- Views: 66
Re: Electrochemical Series
So given a reaction, we should be able to know if it is in its reduction or oxidation form?
- Sun Mar 01, 2020 5:29 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Free energy
- Replies: 3
- Views: 94
Free energy
What do we need to know about the relationship between free energy and cell potentials?
- Sun Mar 01, 2020 5:07 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electrochemical Series
- Replies: 3
- Views: 66
Electrochemical Series
From the learning outcomes, what does it mean that we should understand what is meant by the electrochemical series?
- Sun Mar 01, 2020 5:02 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Calculating E°cell
- Replies: 2
- Views: 48
Calculating E°cell
What is the difference between E°cell= E°cathode − E°anode and E°cell= E°+E° and when would I use one over the other?
- Sun Feb 16, 2020 6:18 pm
- Forum: Balancing Redox Reactions
- Topic: Half reactions
- Replies: 7
- Views: 103
Re: Half reactions
When balancing redox reactions, are we balancing the number of atoms or electrons?
- Sun Feb 16, 2020 5:25 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Equilibrium [ENDORSED]
- Replies: 3
- Views: 73
Equilibrium [ENDORSED]
When a reaction of a system is at equilibrium, why is there no work done by the reaction?
- Sun Feb 16, 2020 5:21 pm
- Forum: Van't Hoff Equation
- Topic: Temperature and K
- Replies: 2
- Views: 52
Temperature and K
How is K temperature dependent using the Van't Hoff Equations?
- Sun Feb 16, 2020 5:09 pm
- Forum: Balancing Redox Reactions
- Topic: Half reactions
- Replies: 7
- Views: 103
Half reactions
In lecture, a redox reaction was separated into half reactions. What are half reactions and how are they separated?
- Sun Feb 16, 2020 3:39 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Pressure
- Replies: 3
- Views: 67
Pressure
Does pressure affect free energy? If it does how?
- Sat Feb 08, 2020 9:59 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Entropy and Pressure
- Replies: 3
- Views: 52
Re: Entropy and Pressure
I think that when pressure increases, volume decreases and when volume decreases entropy also decreases.
- Sat Feb 08, 2020 8:42 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Predicting Entropy
- Replies: 2
- Views: 71
Predicting Entropy
What compositions and conditions of a system would help predict which of two systems has the greater entropy?
- Sat Feb 08, 2020 8:12 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Measuring ∆G°
- Replies: 2
- Views: 53
Measuring ∆G°
In class on Friday, it was mentioned that ∆G°is not measured directly. What does it mean that ∆G°is not measured directly?
- Fri Feb 07, 2020 10:44 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Spontaneous Reaction
- Replies: 8
- Views: 84
Spontaneous Reaction
How do you how Gibbs Free Energy change accompanying a process is related to the direction of a spontaneous reaction? Does it mean that when ∆G is negative, a reaction is spontaneous?
- Fri Feb 07, 2020 10:35 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: ∆H and q
- Replies: 1
- Views: 55
∆H and q
∆Ssurr=q(rev)/T can also be written as ∆Ssurr=∆H(sys)/T. Why can ∆H be used in place of q?
- Sun Feb 02, 2020 8:38 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: Microstates
- Replies: 4
- Views: 123
Microstates
What is the relationship between microstates and degeneracy? Are they the same thing or are the number of microstates related to degeneracy?
- Sun Feb 02, 2020 8:01 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Identifying
- Replies: 4
- Views: 59
Identifying
In thermodynamic, why is it necessary to identify which type of system a reaction is occurring in?
- Sun Feb 02, 2020 7:43 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: deltaU and deltaH
- Replies: 4
- Views: 46
deltaU and deltaH
What are the differences and similarities between deltaU and deltaH?
- Sun Feb 02, 2020 7:38 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Constant Pressure
- Replies: 2
- Views: 26
Constant Pressure
When a reaction has a constant pressure, why is PdeltaV insignificant when the reaction involves solids and liquids?
- Sun Feb 02, 2020 7:36 pm
- Forum: Calculating Work of Expansion
- Topic: Volume
- Replies: 3
- Views: 31
Volume
What is the relationship between volume and work? What would happen if volume increases/decreases?
- Sat Jan 25, 2020 2:09 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase changes
- Replies: 7
- Views: 56
Phase changes
Are phase changes identified by a change from solid to liquid to gas and vice versa? And why does temperature remain constant during a phase change?
- Sat Jan 25, 2020 1:49 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Standard state
- Replies: 3
- Views: 25
Standard state
What is the standard state of a substance and how do I know if a substance is in its standard state?
- Sat Jan 25, 2020 9:31 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Melting and freezing
- Replies: 7
- Views: 79
Re: Melting and freezing
Yes, freezing would be an exothermic reaction because heat is released.
- Sat Jan 25, 2020 9:24 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 5
- Views: 54
Hess's Law
What is Hess's Law and how does it relate to state properties?
- Sat Jan 25, 2020 9:21 am
- Forum: Phase Changes & Related Calculations
- Topic: Endothermic and Exothermic
- Replies: 13
- Views: 102
Endothermic and Exothermic
How do you tell whether a reaction is endothermic or exothermic by the direction of heat flow?
- Fri Jan 17, 2020 8:49 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: pH values of weak and strong acids
- Replies: 6
- Views: 57
pH values of weak and strong acids
Can someone explain why solutions of weak acids have higher pH values than solutions of strong acids at the
same concentration?
same concentration?
- Fri Jan 17, 2020 8:46 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Solubility
- Replies: 2
- Views: 44
Solubility
How do we use equilibrium constants to predict solubility?
- Thu Jan 16, 2020 11:03 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Acids and Bases on test?
- Replies: 3
- Views: 32
Re: Acids and Bases on test?
There are learning outcomes for acids and bases on our class website. The link for the acid and bases learning outcomes: https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14B/Chem14B_Outline2_Acids_and_Bases.pdf
- Thu Jan 16, 2020 8:14 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Weak and strong acids/bases
- Replies: 2
- Views: 23
Weak and strong acids/bases
What is the difference between calculating weak acids or bases and strong acids or bases?
- Thu Jan 16, 2020 3:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Approximation
- Replies: 8
- Views: 70
Re: Approximation
You would add for the reactants and subtract for products
- Fri Jan 10, 2020 2:08 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: N2+3H2<->2NH3
- Replies: 5
- Views: 60
N2+3H2<->2NH3
What happens if N2 is increased, NH3 is increased, or H2 decreased? What does it mean when they go to the left or right?
- Thu Jan 09, 2020 1:19 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q vs K
- Replies: 8
- Views: 85
Re: Q vs K
Q and K are similar in that they are calculated in the same way, Q = [P]/[R] and K = [P]/[R].
- Thu Jan 09, 2020 12:55 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G3
- Replies: 8
- Views: 69
Re: 5G3
Gases are included in equilibrium constant equations.
- Thu Jan 09, 2020 12:41 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G.1C
- Replies: 3
- Views: 66
Re: 5G.1C
The equilibrium constant will remain the same because it is not affected by the amount of reactants or products. If there is a higher pressure of reactant, the pressure of the products will change so that it equals the equilibrium constant, which remains constant.
- Thu Jan 09, 2020 12:11 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5G.7
- Replies: 2
- Views: 49
Re: 5G.7
Kp is the partial pressure equilibrium constant, which would be used for gases, but partial pressure can be converted into concentration of a gas by using the ideal gas law. I think because partial pressure can be converted into concentration, Kc can be used for gases.