CHEMISTRY COMMUNITY

Kate Swertfager

I think we are all waiting for the same answers! Professor Lavelle said he would get back to us with more information soon! I think the answers will come when he sends another email.

Kate Swertfager

I think Dr. Lavelle will send a clarifying email soon.

Kate Swertfager

Will we be given the intermediate reactions? Or should we be able to tell from the original reaction? Also how do we tell which intermediate reaction is the slow one?

Kate Swertfager

Use the vertical line! Also make sure to add in the inert metal on both ends separated with another vertical line.

Kate Swertfager

Do Lavelle’s 14B finals usually take the whole 3 hours to finish?

Kate Swertfager

Will the review session Friday 6-9 be Bruin casted?

Kate Swertfager

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Kate Swertfager

start with the two different delta G equations. Set them equal to each other and solve for E. then separately Solve the delta G equation(the one with Estandard) for Estandard. youll then notice you can plug that into the equation you got for E. Also change p/r to q. That is the derivation of Nerst.

Kate Swertfager

on page 550 of the book there is an example where the cathode and anode have flipped sides in the diagram. In class I believe Dr. Lavelle said to look at which one is being reduced and which one is being oxidized and that will tell you which one is the anode/cathode.

Kate Swertfager

Yes the graph of the first order has a negative slope. The slope is -k and since k is always positive the slope is always negative for 1st order.

Kate Swertfager

What do you set rate 1/rate 2 equal to when trying to find m or n. In the example from class, they set it equal to 2 so that it was 2^m= 2 and m was just 1. I’m confused how to know what to set 2^m equal to.

Kate Swertfager

Each time we use the different laws, are we supposed to derive them from the start or are we allowed to plug and chug?

Kate Swertfager

Second page of the thermodynamics outline and all of the electrochemistry outline.

Kate Swertfager

Can we go to any TA for our own?

Kate Swertfager

I loved that love! Thank you now I can down load it!!

Kate Swertfager

Are step up sessions worth the time? I need help but I don’t have a lot of free time to go to a session that might just be the exact thing from class.

Kate Swertfager

Are all diatomic molecules neutral charge?

Kate Swertfager

What makes something a standard quality? When do I know to use standard vs not standard?

Kate Swertfager

Yes! Bcs NH4CL dissociates, it produces more NH4 which is acidic. Having more of an acid will ultimately decrease the pH even if it’s a weak acid.

Kate Swertfager

Most of the questions I’ve come across have stated that the process was reversible or nonreversible. Reversible reactions must be at constant temp as well and that’s why we use the equations for w that includes T not delta T.

Kate Swertfager

I think intensive means that the voltage difference doesn’t depend on the amount of times that the voltage occurs??

Kate Swertfager

Is it because it releases more energy to form bonds than it takes to break bonds? Resulting in a larger negative value?

Kate Swertfager

Since it is an exothermkc reaction, heat is a product and therefore heating up the reaction would add product, shifting the reaction equilibrium to the left towards the reactants.

Kate Swertfager

^^How does a salt bring deliver those charges? I can’t understand what a salt bridge physically is.

Kate Swertfager

Its on the practice midterm so I would study up on it. There is a really good example in the text book.

Kate Swertfager

Only multiply it by 3 if all three of the bonds are broken. IF two of the bonds are broken, then multiply that bond breakage by 2.

Kate Swertfager

How similar will this practice test be to the actual midterm?

Kate Swertfager

I think the best way to remember them is to separate the equations into groups of categories\learning objectives and then by what is constant in the equations. The way they are separated in class notes make it easier so I would try making a study guide from that. rewriting the equations and when you...

Kate Swertfager

If the system doesn’t exchange energy(heat) or matter then it is isolated. If it exchanges Energy(heat) but not matter then it is closed. If it exchanges both then it is open.
An isolated water bottle doesn’t exchange heat with surroundings or matter so it is isolated.

Kate Swertfager

The SI units for pressure are Pascals and for V they are m^3. For work it is Joules so I think Pa times m^3 gives J.

Kate Swertfager

I was talking to a past student and they said that you should familiar yourself with the variables and equation sheet prior to the test. You will have a lot of equations in front of you but it’s important to know which equation and variables to use!

Kate Swertfager

There are adiabatic calorimeters, oxygen bomb calorimeters, and differential scanning calorimeters (DSC). But in this class I’m pretty sure we focus on bomb calorimeters.

Kate Swertfager

I think because the temp change between temp in K and temp in C is the same?

Kate Swertfager

Multiply. Also always look at the units for help. You need moles to cancel

Kate Swertfager

What’s the difference between the delta U and delta H? How do I know when to use which one?

Kate Swertfager

I went to the test bank today to look for past exams but there were none! So I don;t suggest going there for help. 'Im going to stick with the homework problems and reviewing the learning outcomes.

Kate Swertfager

Yes. Homework problems should be from relevant and current lessons from lecture and section. And since we have a test on the first two topics in sections this week, homework should be from those two topics!

Kate Swertfager

It has to be smaller. Also check once you have your x value to make sure its less than 5% of the initial concentration,if it is then its a good approximation.

Kate Swertfager

There is a table in the book. However sometimes you will need the Ka but you only have the KB for the conjugate and you’ll have to use (Ka)(Kb)=Kw relationship to solve for what you need.

Kate Swertfager

Will topic 6G be covered on test one? It’s not on the syllabus but we discussed buffers in class.

Kate Swertfager

Equilibrium constant and ionization constant of water are the same thing in this case.

Kate Swertfager

Will there be a study guide given for test one? Or even just a practice test?

Kate Swertfager

Was 1D’s section TA changed? My class is sitting in section that was supposed to start at 8am and no TA has shown up. It’s now 8:18. We don’t know what to do.

Kate Swertfager

I think of K as the blanket term for the equilibrium constant. Then more specifically we have Kc, Kp and Kw which are all slightly different but refer to the equilibrium constant as well.

Kate Swertfager

On the syllabus, it states that we can do any 5 questions from relevant and current topics. So since we just moved in to acids and bases on Monday I would say we can also do questions from equilibrium.

Kate Swertfager

In the textbook there is a small section describing graphs I believe. Not sure on the page numbers tho. So if it’s in the test it could possibly be tested. Maybe check the objectives and see if it’s there!

Kate Swertfager

Thank you! Will these be posted every week?

Kate Swertfager

K is used at equilibrium. Q can be used at any time during the reaction. You can find Q and then compare it to K. For instance is K=Q, then you know the reaction is at equilibrium.

Kate Swertfager

Coming into the chemistry 14 series was kinda scary for me, since I’ve never taken chemistry before. But after discovering chemistry community and posts like this, I’m very reassured that even if I struggle with the course it will be worth it in the long run(like when I eventually take the mcat). ju...

Kate Swertfager

Adding on to the previous answer with suggesting Khan Academy. They have great videos that flow in a logical and easy to remember way(for FREE). There is a whole section on ideal gases that includes review videos, mini quizzes and written text!

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