Search found 38 matches

by Alexis Sanft 1E
Sun Feb 21, 2021 9:46 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Work in a Constant Volume
Replies: 13
Views: 34

Re: Work in a Constant Volume

Does this have anything to do with neutralization of a reaction, and if not what exactly is neutralization of a reaction and how do we know what we are solving for in this type of reaction?
by Alexis Sanft 1E
Sun Feb 21, 2021 9:43 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Reversible vs Irreversible Entropy Calculation
Replies: 4
Views: 16

Re: Reversible vs Irreversible Entropy Calculation

Simrah_Ahmed1J wrote:For ΔS...

reversible(isothermal): there is a change in V, no change in T
ΔS= n*R*ln(V2/V1)

irreversible: there is a change in T, no change in V
ΔS= n*Cv*ln(T2/T1)

So irreversible is never isothermal?
by Alexis Sanft 1E
Sun Feb 21, 2021 9:43 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: State function?
Replies: 36
Views: 107

Re: State function?

This does not really have to do with state function, but can somebody tell me how disfunction and stability correlate? Does stability increase or decrease with disorder?
by Alexis Sanft 1E
Sun Feb 21, 2021 9:41 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Trouton's rule
Replies: 4
Views: 11

Re: Trouton's rule

I do not remember learning this yet, but that could just be because I have a bad memory. So, if anyone else remember I would like to know as well.
by Alexis Sanft 1E
Sun Feb 21, 2021 9:40 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Sapling Weeks 5/6 #16
Replies: 5
Views: 22

Re: Sapling Weeks 5/6 #16

n and m refer to the molar coefficients here, and you multiply that molecules standard Gibbs free energy number by that molar coefficient.
by Alexis Sanft 1E
Sun Feb 14, 2021 7:19 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Using CV versus nCV
Replies: 3
Views: 14

Re: Using CV versus nCV

When do we have to worry about Cp?
by Alexis Sanft 1E
Sun Feb 14, 2021 7:18 pm
Forum: Administrative Questions and Class Announcements
Topic: struggling
Replies: 73
Views: 261

Re: struggling

You definitely are not alone! For me the book questions really help, but also going to office hours with your TA and getting one on one extra practice is also really beneficial.
by Alexis Sanft 1E
Sun Feb 14, 2021 7:16 pm
Forum: Van't Hoff Equation
Topic: Celcius vs Kelvin for T1 and T2
Replies: 61
Views: 303

Re: Celcius vs Kelvin for T1 and T2

You generally stick to Kelvin but there was a sapling question that asked for the answer in terms of Celsius, so just make sure you double check to see what the question is actually asking for.
by Alexis Sanft 1E
Sun Feb 14, 2021 7:15 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Units
Replies: 20
Views: 47

Re: Units

I find its best to make sure all your units line up with the units they give in the equation before doing any calculations, so you don't forget at the end.
by Alexis Sanft 1E
Sun Feb 14, 2021 7:12 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Sapling 5/6 #9
Replies: 4
Views: 25

Re: Sapling 5/6 #9

To find the surroundings you use the equation Δ Ssurr = −Δ Hsys / T. To find the universe you use the equation ΔSuniv = ΔSsys + ΔSsurr. I hope this helps.
by Alexis Sanft 1E
Sun Feb 07, 2021 8:23 pm
Forum: Student Social/Study Group
Topic: Midterm 2 study tips
Replies: 26
Views: 75

Re: Midterm 2 study tips

For anyone who assigned the step up sessions, would you guys recommend doing this? How helpful were they with preparing you for the midterm?
by Alexis Sanft 1E
Sun Feb 07, 2021 8:22 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: deltaU
Replies: 29
Views: 104

Re: deltaU

I am confused about the difference between q and delta U, because in question 20 on the sapling assignment they were equal to each other? Was that for a specific reason, or will they always be equal to each other?
by Alexis Sanft 1E
Sun Feb 07, 2021 8:19 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sapling #10 Week 3/4
Replies: 6
Views: 34

Re: Sapling #10 Week 3/4

I was also confused on this problem. Are we just supposed to know the conversion factors for ice in an enthalpy fusion problem?
by Alexis Sanft 1E
Sun Feb 07, 2021 8:16 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity of Calorimeter
Replies: 7
Views: 32

Re: Heat Capacity of Calorimeter

I was just wondering, how we are supposed to know if something is a an atom, linear molecule, or nonlinear molecule, like those pertaining to question 20 on the sapling assignment, that were used to fid the heat capacity?
by Alexis Sanft 1E
Sun Feb 07, 2021 8:13 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Sapling #18 Cv and Cp
Replies: 4
Views: 30

Re: Sapling #18 Cv and Cp

The question gives you your Cp value, its the constant pressure for the specific heat, mine was 5R/2. In order to find Cv you do Cp-R, so for me I did 5R/2 - R= 3R/2 or 1.5R. I hope this helps.
by Alexis Sanft 1E
Sun Jan 31, 2021 8:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Strong Ka
Replies: 8
Views: 64

Re: Strong Ka

Is there some sort of rule for knowing if something is a strong or weak acid or base, besides pH values, or do you kind of just have to memorize strong acids and bases?
by Alexis Sanft 1E
Sun Jan 31, 2021 8:21 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy Reactions
Replies: 13
Views: 48

Re: Enthalpy Reactions

Do standard enthalpies ever change, or are they always the same for a specific molecule no matter the reaction?
by Alexis Sanft 1E
Sun Jan 31, 2021 8:16 pm
Forum: Phase Changes & Related Calculations
Topic: Vapor vs gas
Replies: 92
Views: 249

Re: Vapor vs gas

Are the only possible changes of substances those of gas, liquids,and solids converting into one another? Are there any other ones?
by Alexis Sanft 1E
Sun Jan 31, 2021 8:14 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: How Does Temperature Affect the Equilibrium Constant?
Replies: 25
Views: 76

Re: How Does Temperature Affect the Equilibrium Constant?

If the enthalpy of the reaction is positive, then you know the reaction is endothermic and requires energy. This also means that since the reaction is endothermic and requires energy, then an increase in temperature will lead to your K value increasing, essentially making Q<K, and causing a shift to...
by Alexis Sanft 1E
Sun Jan 31, 2021 8:09 pm
Forum: Calculating Work of Expansion
Topic: Work on the Surroundings
Replies: 3
Views: 23

Re: Work on the Surroundings

the equation for work is w=−PΔV and work is being done when w is negative. That means in order for work to be done ΔV must be a positive value. So we know work is being done with the volume increases in a chemical equation. You can figure this out by looking at the moles in the reactants versus the...
by Alexis Sanft 1E
Sun Jan 24, 2021 11:40 pm
Forum: Ideal Gases
Topic: Gas Constant Value
Replies: 43
Views: 131

Re: Gas Constant Value

Does anyone know if Lavelle is also strict on significant figures? I just want to make sure that I do not loose easy points on the midterm, so if anyone who has taken him previously could say, I would appreciate it!
by Alexis Sanft 1E
Sun Jan 24, 2021 11:39 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: closed system
Replies: 43
Views: 275

Re: closed system

Closed systems have a fixed amount of matter and allow the transfer of energy as heat. Volume can actually be changed in such a system but it would most likely be as a result of a change by the experimenter such as moving a piston up or down to change volume and pressure. So, does the transfer of e...
by Alexis Sanft 1E
Sun Jan 24, 2021 11:35 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Temperature Given in Problems
Replies: 6
Views: 13

Re: Temperature Given in Problems

A lot of the problems give a temperature in them, but I don't know when we have to take it into account and when we don't. When reactions take place at the same temperature, like for example in #7 and #8 on the Week 2 Sapling the Ka and Kb take place under the same conditions, I've been told we can...
by Alexis Sanft 1E
Sun Jan 24, 2021 11:33 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Sapling 9
Replies: 10
Views: 67

Re: Sapling 9

Also, do we need to do any actual calculations if the pkA is given and the pH is given?
by Alexis Sanft 1E
Sun Jan 24, 2021 11:31 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Sapling 9
Replies: 10
Views: 67

Re: Sapling 9

What does it mean to be a "predominant" species?
by Alexis Sanft 1E
Sun Jan 24, 2021 11:31 pm
Forum: Phase Changes & Related Calculations
Topic: weak/strong bases and acids
Replies: 7
Views: 27

Re: weak/strong bases and acids

Do any of you guys know if we are expected to know if something is a weak or strong base off of memorization for the midterm?
by Alexis Sanft 1E
Sun Jan 17, 2021 7:18 pm
Forum: General Science Questions
Topic: class 1/18/21
Replies: 13
Views: 93

Re: class 1/18/21

Does anyone know when the Chemistry Community posts are supposed to be done by each week? I know we are supposed to have posted five times each week, but what day are our posts actually due?
by Alexis Sanft 1E
Sun Jan 17, 2021 7:17 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterms
Replies: 24
Views: 72

Re: Midterms

As someone who didn't take 14A with Lavelle how is the midterm formatted? My TA told us we will be in a zoom room with our TA and it will be administered over respondus and it will be multiple choice. We will be able to use a calculator and are expected to show our surroundings. I hope that helps. ...
by Alexis Sanft 1E
Sun Jan 17, 2021 7:14 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Post Assessment Question 15 Part 4
Replies: 3
Views: 14

Re: Post Assessment Question 15 Part 4

For the exam do you guys know if we will be tested on endothermic and exothermic reactions, like will we have to know if a reaction is endothermic or exothermic?
by Alexis Sanft 1E
Sun Jan 17, 2021 7:12 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: % Ionization and % Protonation
Replies: 11
Views: 74

Re: % Ionization and % Protonation

Shreya Patel- 2D wrote:What's the difference between protonation and ionization then?

Does anyone know if we are supposed to have already learned this and if there will be questions on this on the exam?
by Alexis Sanft 1E
Sun Jan 17, 2021 7:12 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: % Ionization and % Protonation
Replies: 11
Views: 74

Re: % Ionization and % Protonation

When working with acids and bases and conjugate acids and bases, will the acid or base always be on the reactant side of the reaction being formed and the conjugate acid or base always be on the product side?
by Alexis Sanft 1E
Sun Jan 17, 2021 7:10 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Ka and Kb
Replies: 5
Views: 34

Re: Ka and Kb

Hi, I was wondering how you know in an equation which one is the base and which one is the acid, and if we are expected to know how to figure that out or if it will be stated in a problem?
by Alexis Sanft 1E
Sat Jan 09, 2021 2:18 pm
Forum: Student Social/Study Group
Topic: Final Exam Study Tips
Replies: 48
Views: 284

Re: Final Exam Study Tips

I learned from last quarter to spread out my studying and to avoid cramming in this class. Attending workshops and step-up sessions throughout the quarter is really helpful for staying on top of information. Using outside resources such as Khan Academy is also really helpful! Hi I was wondering wha...
by Alexis Sanft 1E
Sat Jan 09, 2021 2:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5
Replies: 11
Views: 116

Re: Sapling #5

Hi, the easiest way I think to approach this problem is to combine the formulas that make up the reaction given, by putting them on top of one another, then cancel out any repeating terms that appear on the reactant side of one of the combined formulas, and the product side of the other in which aft...
by Alexis Sanft 1E
Thu Jan 07, 2021 6:43 pm
Forum: Administrative Questions and Class Announcements
Topic: Sapling Assignments
Replies: 28
Views: 158

Re: Sapling Assignments

Hi, I was wondering if anyone knew if the Sapling questions were due this coming Sunday as in three days from now, or if it is due next Sunday as in a week and three days from now. I know Sapling says that the first assignment is due Sunday of week 2, but I did not want miss anything, so if someone ...
by Alexis Sanft 1E
Thu Jan 07, 2021 6:33 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 107
Views: 7327

Re: Accessing the E-textbook [ENDORSED]

I purchased the sapling+ 7th edition ebook a few days ago from ucla and have not received a notification for the prepaid code to access sapling. Does anybody have a solution or are in a similar situation? Thanks. Hi, I had the exact same problem, because I did not previously take 14A with Lavelle. ...
by Alexis Sanft 1E
Wed Jan 06, 2021 6:58 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 107
Views: 7327

Re: Accessing the E-textbook [ENDORSED]

I am not sure if anyone has already covered this, but regarding what is due on Sapling, are the problems posted on Sapling the only problems each week that we are graded on? I know you are supposed complete the assigned work each week, but are the additional practice problems from the textbook just ...
by Alexis Sanft 1E
Wed Jan 06, 2021 6:40 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Posts in 14B
Replies: 156
Views: 2342

Re: Chemistry Posts in 14B

Sorry if someone already asked this but do the points roll over to the next week? Like do we have to do 5 per week or would 4 one week and then 6 the next be okay? Hi, this is my first time taking Lavelle but from what I have gathered we have to post 5 times each week and the points do not roll ove...

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