Search found 50 matches

by Julia Holsinger_1A
Sun Mar 15, 2020 6:36 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Delta S
Replies: 8
Views: 80

Re: Delta S

When using the equation (delta)S= C ln(T2/T1), How do you know which heat capacity to use?
by Julia Holsinger_1A
Sun Mar 15, 2020 6:33 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Finding enthalpy
Replies: 2
Views: 29

Re: Finding enthalpy

Also when there is constant pressure and no expansion work, (delta)H=q
by Julia Holsinger_1A
Sun Mar 15, 2020 6:29 am
Forum: Phase Changes & Related Calculations
Topic: phase change
Replies: 6
Views: 55

Re: phase change

Like the diagram in class, you can tell that there is a phase change when the heat or enthalpy is increasing, but the temperature is not increasing, or delta T is zero. Can the enthalpy increase AND the temperature remains the same while there still not being a phase change? Like I'm imagining the ...
by Julia Holsinger_1A
Sat Mar 14, 2020 4:15 pm
Forum: First Order Reactions
Topic: Linear versus Non-Linear
Replies: 3
Views: 22

Re: Linear versus Non-Linear

Would there ever be a first order linear slope that is positive and not negative?
by Julia Holsinger_1A
Sat Mar 14, 2020 4:08 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 8
Views: 33

Re: Catalysts

How do you spot a catalyst in a reaction? Or will it always be given?
by Julia Holsinger_1A
Sat Mar 14, 2020 4:07 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation
Replies: 6
Views: 44

Re: Nernst Equation

I convert RT/F to 0.025693 V and it has always given me the correct answer when I plug it in. I think you need to be careful of how you round if you are calculating RT/nF
by Julia Holsinger_1A
Sat Mar 14, 2020 4:05 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Test 2 #6 b
Replies: 1
Views: 15

Test 2 #6 b

For question 6 part b) How will each of the following changes affect the cell potential: i) adding 100 mL pure water to cathode solution ii) halving the mass of anode electrode I am a bit confused with i) and how the cell potential would decrease when adding 100mL of water into the solution because ...
by Julia Holsinger_1A
Sat Mar 14, 2020 3:59 pm
Forum: Van't Hoff Equation
Topic: Test 2 Calculate K after a temperature change
Replies: 1
Views: 28

Re: Test 2 Calculate K after a temperature change

make sure to set up the equation by first isolating ln(K2). So the equation would be: ln(K2)=(deltaH/R) (1/T1 - 1/T2) + ln(K1). Then plug in your numbers. I have found that when I don't isolate the ln(K2) first I get a strange answer.
by Julia Holsinger_1A
Sat Mar 14, 2020 3:55 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equations
Replies: 8
Views: 49

Re: Equations

In the text book I am seeing lots of equations that have (delta)G sub r, what does the r mean? I think its just reaction but I am not positive.
by Julia Holsinger_1A
Sat Mar 14, 2020 3:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constants
Replies: 8
Views: 31

Re: Equilibrium Constants

When the equilibrium constant K is larger than 10^3 does the reaction favor the products or the reactants?
by Julia Holsinger_1A
Sat Mar 14, 2020 10:35 am
Forum: First Order Reactions
Topic: Half Life
Replies: 13
Views: 52

Re: Half Life

How do you determine the order of the reaction when needing to calculate half life? Will it always be given? To determine the order, you will likely use scientific data, are told, or can assume pseudo-first reaction if the information permits. I am a bit confused about psuedo-first reaction, could ...
by Julia Holsinger_1A
Sat Mar 14, 2020 10:20 am
Forum: First Order Reactions
Topic: Half Life
Replies: 13
Views: 52

Re: Half Life

How do you determine the order of the reaction when needing to calculate half life? Will it always be given?
by Julia Holsinger_1A
Thu Mar 12, 2020 1:51 pm
Forum: First Order Reactions
Topic: Half Life
Replies: 8
Views: 44

Re: Half Life

How do you determine time (t) when given half life and the percentage something has decreased? EX: from self-test 7B.4A: In 1972, grain treated with methyl mercury was released for human consumption in Iraq, resulting in 459 deaths. The half-life of methyl mercury in body tissues is 70 days. How man...
by Julia Holsinger_1A
Thu Mar 12, 2020 12:37 pm
Forum: Administrative Questions and Class Announcements
Topic: Take Home Final
Replies: 16
Views: 186

Re: Take Home Final

Does anyone know how much time we will be given to do the final?
by Julia Holsinger_1A
Thu Mar 12, 2020 12:17 pm
Forum: General Rate Laws
Topic: Rate limiting step
Replies: 13
Views: 44

Re: Rate limiting step

How do you find the limiting step?
by Julia Holsinger_1A
Thu Mar 12, 2020 12:17 pm
Forum: General Rate Laws
Topic: Rate limiting step
Replies: 13
Views: 44

Re: Rate limiting step

It is the slowest step in the reaction
by Julia Holsinger_1A
Thu Mar 12, 2020 12:12 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: determining k
Replies: 6
Views: 27

determining k

when trying to determine k, can you use any trial (when looking at multiple trials)?
by Julia Holsinger_1A
Thu Mar 12, 2020 9:59 am
Forum: Student Social/Study Group
Topic: Week 10 Review Question
Replies: 5
Views: 63

Week 10 Review Question

From Lavelle's Week 10 Review slides that he posted, On the first slide, how do you get the change in molar concentration? I am confused with how 0.075 and 0.225 were calculated.
by Julia Holsinger_1A
Wed Mar 11, 2020 5:05 pm
Forum: Balancing Redox Reactions
Topic: Half rxns
Replies: 27
Views: 213

Re: Half rxns

When balancing basic half reactions, how do you know which side to put the OH- versus the H2O?
by Julia Holsinger_1A
Wed Mar 11, 2020 5:04 pm
Forum: Balancing Redox Reactions
Topic: Half rxns
Replies: 27
Views: 213

Re: Half rxns

005384106 wrote:At what point do you add elections to the half reaction?

When all other elements are balanced and you just need to balance the charge of both sides
by Julia Holsinger_1A
Wed Mar 11, 2020 5:02 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Electromotive force (emf)
Replies: 9
Views: 85

Re: Electromotive force (emf)

005384106 wrote:Why do we measure the voltage difference of two cells?

The difference in potential voltage is what gives rise to electric current
by Julia Holsinger_1A
Wed Mar 11, 2020 4:59 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Relationship Between Ecell and K
Replies: 9
Views: 49

Re: Relationship Between Ecell and K

Ecell and K are positively related so the larger the K means a more positive Ecell
by Julia Holsinger_1A
Wed Mar 11, 2020 4:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Going from pKa to pH
Replies: 10
Views: 79

Re: Going from pKa to pH

What does the w in pKw stand for?
by Julia Holsinger_1A
Tue Mar 10, 2020 6:16 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram and Ecell [ENDORSED]
Replies: 10
Views: 32677

Re: Cell Diagram and Ecell [ENDORSED]

bloodorangefield wrote:How do you tell the difference between when it is an anode vs when it is cathode?


anode is always on the left and cathode is on the right
by Julia Holsinger_1A
Tue Mar 10, 2020 6:07 pm
Forum: Second Order Reactions
Topic: 2nd Order Slope
Replies: 2
Views: 17

2nd Order Slope

Will the 2nd order slope ever be negative when plotting?
by Julia Holsinger_1A
Tue Mar 10, 2020 6:01 pm
Forum: Van't Hoff Equation
Topic: Van’t Hoff Equation
Replies: 11
Views: 118

Re: Van’t Hoff Equation

How do you know to use Van't Hoff Equation? Are there certain questions in problems that signal to use it?
by Julia Holsinger_1A
Tue Mar 10, 2020 5:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Using Equilibrium constants to predict solubility
Replies: 4
Views: 15

Re: Using Equilibrium constants to predict solubility

Also what is the relationship between the constants and solubility? are they positively correlated or negatively correlated?
by Julia Holsinger_1A
Tue Mar 10, 2020 5:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Using Equilibrium constants to predict solubility
Replies: 4
Views: 15

Using Equilibrium constants to predict solubility

How do you use Equilibrium constants to predict solubility? Would you use Le Chatelier's principle?
by Julia Holsinger_1A
Tue Mar 10, 2020 5:54 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Ka Kb
Replies: 11
Views: 56

Re: Ka Kb

What is the difference between pKa and Ka? same for pKb and Kb.
by Julia Holsinger_1A
Tue Mar 10, 2020 5:54 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Strong/weak acids & bases
Replies: 14
Views: 111

Re: Strong/weak acids & bases

How do you figure out the conjugate acid or base for a given base or acid?
by Julia Holsinger_1A
Tue Mar 10, 2020 5:52 pm
Forum: Ideal Gases
Topic: ideal gases
Replies: 13
Views: 104

Re: ideal gases

How do you distinguish if something is an ideal gas?
by Julia Holsinger_1A
Sun Mar 01, 2020 8:33 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Oxidation Numbers
Replies: 5
Views: 21

Oxidation Numbers

What are the rules for oxidation numbers? I am having trouble getting the n in while trying to calculate the Gibbs Free Energy when given cell potential.
by Julia Holsinger_1A
Tue Feb 11, 2020 10:04 pm
Forum: Administrative Questions and Class Announcements
Topic: Pizza Rolls REVIEW Session DOWNLOAD HERE
Replies: 67
Views: 2550

Re: Pizza Rolls REVIEW Session DOWNLOAD HERE

Asha Agarwal 1E wrote:Can someone also explain #12B? Is there a specific equation to use?

You take the q=mC(delta)T of each part of the equation while using the Cpm values given for C and then you do the sum of the products minus the sum of the reactants.
by Julia Holsinger_1A
Tue Feb 11, 2020 8:02 pm
Forum: Administrative Questions and Class Announcements
Topic: Pizza Rolls REVIEW Session DOWNLOAD HERE
Replies: 67
Views: 2550

Re: Pizza Rolls REVIEW Session DOWNLOAD HERE

I am confused with #12B. What equation do you use when trying to find delta H?
by Julia Holsinger_1A
Sun Feb 09, 2020 8:11 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: difference between molar entropies?
Replies: 6
Views: 35

Re: difference between molar entropies?

Standard entropies tend to increase with increasing molar mass.
by Julia Holsinger_1A
Sun Feb 09, 2020 8:09 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Ideal Gas Chart
Replies: 3
Views: 25

Re: Ideal Gas Chart

Could someone please summarize this chart please? What is R and why would it be the way it is on the chart? the gas chart is for monoatomic and diatomic ideal gases. Monoatomic Internal energy: 3/2nRT . Monoatomic molar Cv: 3/2 R . Monoatomic molar Cp: 5/2 R Diatomic Internal energy: 5/2nRT . Diato...
by Julia Holsinger_1A
Sun Feb 09, 2020 7:54 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Ideal Gas Chart
Replies: 3
Views: 25

Ideal Gas Chart

When are you supposed to use the chart for the monoatomic and diatomic that give Molar heat capacities? (ex. 3/2 R)
by Julia Holsinger_1A
Sun Feb 09, 2020 7:51 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Cv Cp
Replies: 3
Views: 32

Re: Cv Cp

For constant pressure the equation is W= -P(delta)V , what is the equation for constant volume?
by Julia Holsinger_1A
Mon Feb 03, 2020 10:29 pm
Forum: Van't Hoff Equation
Topic: Van't Hoff
Replies: 6
Views: 51

Van't Hoff

When do you use the Van Hoff equation?
by Julia Holsinger_1A
Mon Feb 03, 2020 10:28 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: q and w
Replies: 10
Views: 83

Re: q and w

Work will be negative if the system is expanding and will be positive if the system is compressing.
by Julia Holsinger_1A
Mon Feb 03, 2020 10:25 pm
Forum: Calculating Work of Expansion
Topic: Integrals
Replies: 2
Views: 20

Integrals

How do you know to use the integral when calculating the Work of Expansion?
by Julia Holsinger_1A
Mon Feb 03, 2020 8:53 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Molar Heat Capacity
Replies: 4
Views: 33

Molar Heat Capacity

How do you calculate the molar heat capacity?
by Julia Holsinger_1A
Sun Jan 26, 2020 10:57 pm
Forum: Phase Changes & Related Calculations
Topic: Hess's Law
Replies: 8
Views: 39

Re: Hess's Law

How can you prove that the total enthalpy change is the sum of the changes in it?
by Julia Holsinger_1A
Sun Jan 26, 2020 10:48 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Spontaneous reactions
Replies: 9
Views: 1576

Re: Spontaneous reactions

Does gibbs free energy determine spontaneity and enthalpy? Or only enthalpy?
by Julia Holsinger_1A
Mon Jan 20, 2020 10:46 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H20 in the ICE table
Replies: 26
Views: 152

Re: H20 in the ICE table

I believe ICE table only pertains to gases
by Julia Holsinger_1A
Mon Jan 20, 2020 10:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Module
Replies: 4
Views: 30

Re: Module

I am still getting 2.2 even when I calculate the concentration of H2 and AsH3 by divided moles by 3.00L
by Julia Holsinger_1A
Mon Jan 20, 2020 10:25 pm
Forum: Ideal Gases
Topic: Topics on Test 1
Replies: 37
Views: 268

Re: Topics on Test 1

Jaci Glassick 2G wrote:I know this is a bit away, but does anyone what topics will be covered on Test 1? Thank you!

Chemical Equilibrium and Acid and Base Equilibria

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