Search found 30 matches

by Sable Summerfield
Mon Feb 15, 2021 2:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm 2
Replies: 14
Views: 49

Re: Midterm 2

Is it only covering topics from week 4 through 6?
by Sable Summerfield
Mon Feb 15, 2021 2:23 pm
Forum: Student Social/Study Group
Topic: Studying for Midterm 2
Replies: 45
Views: 182

Re: Studying for Midterm 2

I would say that the homework problems you are doing would be the most helpful. I'd focus on the multistep word problems near the end of each section because they require you to combine all of the information from the chapter. What if you are stuck on a homework problem or multi-step problem and yo...
by Sable Summerfield
Mon Feb 15, 2021 10:42 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy Transfer
Replies: 3
Views: 20

Re: Entropy Transfer

I also struggled with this concept, but as Professor Lavelle explained in the lecture: delta S = delta H / T. The delta H values of both the surroundings and system are equal and opposite of one another. However, this is not necessarily true for the delta S values, because when you release/absorb h...
by Sable Summerfield
Sat Feb 13, 2021 10:38 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling week 5 and 6 question #6
Replies: 4
Views: 19

Re: Sapling week 5 and 6 question #6

I figured it out! If anyone is wondering.... use the equation: delta S total= Delta SV+ delta ST.
So, solve for delta SV and delta ST separately and add together. I forgot to multiply by r=8.314 in volume equation.
by Sable Summerfield
Sat Feb 13, 2021 10:27 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Sapling week 5 and 6 question #6
Replies: 4
Views: 19

Sapling week 5 and 6 question #6

I don't know what I am doing wrong... could you please explain this problem from the beginning?
by Sable Summerfield
Sun Feb 07, 2021 11:25 pm
Forum: Calculating Work of Expansion
Topic: Sapling #14: Why do we use two different values of R for Path A?
Replies: 5
Views: 28

Re: Sapling #14: Why do we use two different values of R for Path A?

Hi! With the help of Chemistry Community, I was able to solve this problem. However, I'm still confused on why we use two different R values (0.08206 atm*L/(K*mol) and 8.13 J/(K*mol)). How do we know when to use each R value? Here's the question below for reference. Thank you! A sample of an ideal ...
by Sable Summerfield
Sun Feb 07, 2021 11:21 pm
Forum: Calculating Work of Expansion
Topic: The Sign of Work
Replies: 7
Views: 21

Re: The Sign of Work

How do you know which is the best and correct equation to use when dealing with work? I feel like there are quite a few and I am never sure which one to use in certain circumstances. Especially in problem #18 on homework for week 3 and 4. Any tips?
by Sable Summerfield
Sun Feb 07, 2021 11:14 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sapling Hw Week 4 #10
Replies: 5
Views: 28

Re: Sapling Hw Week 4 #10

Hey Emily! So, the way to start is by converting g to moles and then multiply by the deltaH (enthalpy) to find Joules which is quantified as heat energy. You have to find the delta Hfusion to know how much heat it took to go from solid to liquid. You then add the Joules from the icecube melting to y...
by Sable Summerfield
Sun Feb 07, 2021 10:17 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Atoms, Linear, Non- Linear Molecules?
Replies: 9
Views: 27

Atoms, Linear, Non- Linear Molecules?

On week 3-4 homework due week 5, I don't know how to tell if the gas is classified as: Atoms, Linear, Non- Linear Molecules?

For CO2 I have seen it represented as linear and non-linear.
by Sable Summerfield
Sun Feb 07, 2021 10:16 am
Forum: Administrative Questions and Class Announcements
Topic: Set-up Program and Workshops
Replies: 2
Views: 25

Set-up Program and Workshops

I have tried to go to two set up programs and neither of them have been active. It just says waiting for host to start the meeting. I got the link from the hyperlinked document and a went to a drop-in session on Friday with this document and it was great. Are the sessions just canceled sometimes? Wh...
by Sable Summerfield
Fri Feb 05, 2021 1:23 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeters
Replies: 15
Views: 76

Re: Calorimeters

I found it helpful during Sapling week 3-4 that you put the negative sign on the right side of your equation when solving Tfinal when it is an exothermic reaction and it is releasing heat, so the value of Tfinal on the right will decrease. You know it will be flipped and the negative sign will be in...
by Sable Summerfield
Fri Feb 05, 2021 1:09 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sapling homework #10
Replies: 4
Views: 49

Re: Sapling homework #10

first convert from grams to moles and then multiply the moles by deltaH (enthalpy) to find (J) jewels which is heat quantified as energy. You need to find Jewels to know how much heat it took to go from solid to liquid and you take that value which should be 16,008.88 J and add it to the left side o...
by Sable Summerfield
Fri Feb 05, 2021 12:58 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sapling Week 3 & 4 #11
Replies: 4
Views: 58

Re: Sapling Week 3 & 4 #11

Simply put, I solved this by exchanging 0.903J/gC constant for aluminum on the right side of the equation instead of the water constant (4.184) which will still go on the left side of the equation. The left side of the equation will start with a (-) negative sign because it is the water that is loos...
by Sable Summerfield
Fri Feb 05, 2021 12:42 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: W3-W4 Sapling question 12
Replies: 6
Views: 25

Re: W3-W4 Sapling question 12

For part 2 where we find the heat of combustion per gram, what exactly is qB instead of just the q which is the heat of combustion?
by Sable Summerfield
Fri Feb 05, 2021 12:39 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: W3-W4 Sapling question 12
Replies: 6
Views: 25

Re: W3-W4 Sapling question 12

Why in #12 do we need to convert the mass in grams of 1.637 to 50.23 kj in order to use it over delta T in the in the C equation?
by Sable Summerfield
Mon Jan 25, 2021 12:04 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Weak acid vs strong acid
Replies: 4
Views: 30

Re: Weak acid vs strong acid

How can you tell if something is a weak acid or strong acid just by looking at it? Like HA is a weak acid... how will I know that just by looking at it? Maybe that is a bad example but I hope you get the question.
by Sable Summerfield
Mon Jan 25, 2021 12:01 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Sapling Week 2 #7
Replies: 6
Views: 143

Re: Sapling Week 2 #7

I am really confused as to what exactly a hydrolysis reaction is and how the reaction changes mid question like it does in question #8 on week 2 homework. First we have NH4CL -----> NH4+ + CL- and then the hydrolysis reaction occurs and it changes to NH4+ + H2O <-----> NH3 + H+. Why does this happen...
by Sable Summerfield
Sun Jan 24, 2021 11:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: [B]formal
Replies: 5
Views: 32

Re: [B]formal

Bformal is the same as the initial concentration of B. The formal concentration of B is the sum of the concentrations of B and BH+. On sapling, they calculated the concentration of B at equilibrium, not the initial concentration of B, which is why they had to add B (x) and BH+ (B-x) to get to the i...
by Sable Summerfield
Sun Jan 24, 2021 11:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ka and Kb Formula
Replies: 15
Views: 64

Re: Ka and Kb Formula

How do we know when we need to convert Kb to Ka or vice versa?
by Sable Summerfield
Sun Jan 24, 2021 11:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Approximation
Replies: 5
Views: 33

Re: Approximation

I am confused as to when we know we can approximate or not. So we know we can approximate when Kc is very small.... but how small is small and what do we do if we are finding Kc and don't know whether to approximate or use the quadratic formula?
by Sable Summerfield
Sun Jan 17, 2021 10:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: C in ICE Box
Replies: 19
Views: 82

Re: C in ICE Box

So, what exactly does the x mean? Is it like a placeholder for the value of the concentration?
by Sable Summerfield
Sun Jan 17, 2021 10:53 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: When would K be unchanged?
Replies: 31
Views: 93

Re: When would K be unchanged?

Brandon McClelland3L wrote:K generally only changes when temperature changes.


Why does K only change when temperature changes and what EXACTLY does K mean? I know it is the equilibrium constant.. but is this like a ratio between the products and reactants?
by Sable Summerfield
Sun Jan 17, 2021 10:49 pm
Forum: Ideal Gases
Topic: Units for Pressure
Replies: 41
Views: 845

Re: Units for Pressure

What is the difference between Barr and Atm? Why are they interchangeable?
by Sable Summerfield
Sun Jan 17, 2021 10:47 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: q vs k
Replies: 62
Views: 204

Re: q vs k

Is there a less obvious explanation for how Q>K because K decreased and K increased because Q< K? The relationship between Q and K is kind of confusing when getting into why Q is < K when the Reactants transfer to the Products side.
by Sable Summerfield
Sun Jan 17, 2021 10:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Box
Replies: 28
Views: 99

Re: ICE Box

Can someone please explain why we need to use an ICE box when molecules don't completely dissociate?
by Sable Summerfield
Sun Jan 10, 2021 10:09 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and K
Replies: 46
Views: 171

Re: Q and K

You can calculate Q to figure out where the reaction will proceed if given the equilibrium constant, K. Similar to what Silvi said, when Q<K the reaction will proceed to the right and vice versa when Q>K the reaction will proceed to the left. Could we go more in depth as to WHY when Q<K the reactio...
by Sable Summerfield
Sun Jan 10, 2021 9:37 pm
Forum: Student Social/Study Group
Topic: Advice for someone who didn't take 14A with professor Lavelle
Replies: 61
Views: 327

Re: Advice for someone who didn't take 14A with professor Lavelle

Dr. Lavelle has many resources out there but the way they best helped me was by reading and practicing the textbooks and whatever I needed help with or had questions with, I would then go to step up sessions and ask for help or extra practice. How close to the homework and practice problems are the...
by Sable Summerfield
Sun Jan 10, 2021 9:34 pm
Forum: Student Social/Study Group
Topic: Advice for someone who didn't take 14A with professor Lavelle
Replies: 61
Views: 327

Re: Advice for someone who didn't take 14A with professor Lavelle

You should definitely be going to step-up sessions, workshops, and Dr. Lavelle's office hours, but I also recommend doing the homework problems for every outline. I did pretty well on the midterms last quarter, but I definitely underestimated the difficulty of the final, so don't do that. Where is ...
by Sable Summerfield
Sun Jan 10, 2021 9:31 pm
Forum: SI Units, Unit Conversions
Topic: Audio-Visual Focus-Topics, Assessments & Surveys
Replies: 11
Views: 608

Re: Audio-Visual Focus-Topics, Assessments & Surveys

I am wondering at what pace we should complete the assessments and surveys? A set of Pre, Lecture, and post each week? How may sets of three should we complete a week?
by Sable Summerfield
Sun Jan 10, 2021 9:23 pm
Forum: Administrative Questions and Class Announcements
Topic: Accessing the E-textbook [ENDORSED]
Replies: 107
Views: 7267

Re: Accessing the E-textbook [ENDORSED]

I am having a lot of trouble getting into Sapling. If I try to go through CCLE it says it is invalid and if I try to do it through the sapling website it tells me that I need to do it through CCLE. I need to access it asap and my access code is only arriving this week. Please help, I don't knowhow e...

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