CHEMISTRY COMMUNITY

Sable Summerfield

Is it only covering topics from week 4 through 6?

Sable Summerfield

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...

Sable Summerfield

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...

Sable Summerfield

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.

Sable Summerfield

I don't know what I am doing wrong... could you please explain this problem from the beginning?

Sable Summerfield

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 ...

Sable Summerfield

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?

Sable Summerfield

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...

Sable Summerfield

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.

Sable Summerfield

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...

Sable Summerfield

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...

Sable Summerfield

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...

Sable Summerfield

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...

Sable Summerfield

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?

Sable Summerfield

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?

Sable Summerfield

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.

Sable Summerfield

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...

Sable Summerfield

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...

Sable Summerfield

How do we know when we need to convert Kb to Ka or vice versa?

Sable Summerfield

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?

Sable Summerfield

So, what exactly does the x mean? Is it like a placeholder for the value of the concentration?

Sable Summerfield

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?

Sable Summerfield

What is the difference between Barr and Atm? Why are they interchangeable?

Sable Summerfield

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.

Sable Summerfield

Can someone please explain why we need to use an ICE box when molecules don't completely dissociate?

Sable Summerfield

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...

Sable Summerfield

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...

Sable Summerfield

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 ...

Sable Summerfield

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?

Sable Summerfield

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...

CHEMISTRY COMMUNITY

Search found 30 matches

Re: Midterm 2

Re: Studying for Midterm 2

Re: Entropy Transfer

Re: Sapling week 5 and 6 question #6

Sapling week 5 and 6 question #6

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

Re: The Sign of Work

Re: Sapling Hw Week 4 #10

Atoms, Linear, Non- Linear Molecules?

Set-up Program and Workshops

Re: Calorimeters

Re: Sapling homework #10

Re: Sapling Week 3 & 4 #11

Re: W3-W4 Sapling question 12

Re: W3-W4 Sapling question 12

Re: Weak acid vs strong acid

Re: Sapling Week 2 #7

Re: [B]formal

Re: Ka and Kb Formula

Re: Approximation

Re: C in ICE Box

Re: When would K be unchanged?

Re: Units for Pressure

Re: q vs k

Re: ICE Box

Re: Q and K

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

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

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

Re: Accessing the E-textbook [ENDORSED]