CHEMISTRY COMMUNITY

Marina Gollas 1A

I think they would have to tell us, because in most of the hw problems and in the midterm and tests, they told us whether it was in an acidic or basic solution. :)

Marina Gollas 1A

I would assume so, or else we would need to "look them up" as most of the UAs and even Lavelle said during lecture I believe, because memorizing all of the Ecell values would be quite hard haha :) They might even state it in the problem too.:)

Marina Gollas 1A

605168557 wrote:In general for all reactions: aA --> bB + cC

The unique rate is -1/a * d[A]/dt = 1/b * d[B]/dt = 1/c * d[C]/dt

The unique rate is the same for all R & P in that 'unique' reaction

Ohhhh ok so unique rates normally do not have more than one reactants then? Is that what you mean?

Marina Gollas 1A

Ashley P 4I wrote:I believe that test one is posted but not test two.

Where is test 1 posted at?

Marina Gollas 1A

Does anyone know how to calm down your anxieties before you take this final? Since having test anxiety can be very distracting while you're trying to study or even while you're taking the test itself. Open to any tips:)

Marina Gollas 1A

When I went to one of the review sessions, one of the UAs had stated that we use whichever one we are focusing on in the current problem and whichever one you use in your change in entropy equation, since you take into consideration each entropy calculation separately, since there are 2 delta S that...

Marina Gollas 1A

Yeah I have the same question too^. I'm going to try looking for them, and I'll let you know if I find them, but hopefully someone else will respond with an answer before then:)

Marina Gollas 1A

How are we able to figure out the unique rate of the reaction if there are more than one reactants given in the equation? Since I know if there was one reactant you would divide the rate of the reaction by the coefficient of that one reactant, but what if there are more than one? Do we multiply the ...

Marina Gollas 1A

yeah you got it girl!:)

Marina Gollas 1A

Does Lavelle want us to write the exponent of 1 for first order reactions? I just wanted to clarify.
An example could be:
rate=k[A]^1[B]^2

or does he want no exponent of 1? such as rate=k[a][B]^2

Marina Gollas 1A

What is a pseudo first order rate law again? My TA tried to explain it, but I still didn't really understand it. Sorry if this is a dumb question.

Marina Gollas 1A

In Q: 15.19 on the 6th Edition Hw, how come the reaction of B is in second order? The concentration 2 of B was 3.02 and the concentration 1 of B was 1.25. The rate 2 is 50.8 and the rate 1 is 17.4. I end up getting 2.416^n=2.919, so n is about around the 1.2 area. Why did the solutions manual round ...

Marina Gollas 1A

Yeah it matters which one you use depending on the question you are trying to solve, since if the question asks for mmol, then use mmol, and vice versa. They should hopefully let you know in the question towards which units to use, since either they'll be provided, or it'll be specifically asked. :)

Marina Gollas 1A

CH4(g) + 2H2S(g)-------> CS2(g) + 4H2(g) a.) 2.00 mol of CH4, 2.00 mol of CS2, 4.00 mol of H2S, and 4.00 mol of H2 are mixed in a 500 ml vessel at 960 K. Kc=0.046 for this reaction. Show using calculations if this reaction is at equilibrium. If not, which direction will the reaction process? b.) Ful...

Marina Gollas 1A

Sodium Benzoate (NaC7H5O2) is used as a food preservative. What is the pH of a 0.10 M solution of sodium benzoate? The pka of benzoic acid (C2H6O2) is 4.404. Can someone help break this up for me? :) Thank you.

Marina Gollas 1A

How do you balance basic redox reactions if OH and H2O both have O in them? (as opposed to acidic where you can just use H+ and automatically balance the equations)? Basically, what you do is you add the H2O first in the redox half reaction to balance out the Os on the two sides. For example, in th...

Marina Gollas 1A

Question: "Suppose that 3 moles of H2(g) and 6 moles of F2(g) are mixed in a 3L flask. The equilibrium constant (Kc) of the above reaction is 115 at a specific temperature. Calculate the initial concentrations for each chemical species." Just to clarify, can anyone break it down step by st...

Marina Gollas 1A

In Q3 of the Midterm, part D, it states Phosphoric acid is used to acidify foods and beverages such as various colas and jams and provides a tangy or sour taste. Write the reaction that represents Ka2 for phosphoric acid (H3PO4). What would've been the correct answer?

Marina Gollas 1A

In response to your question, I am going to ask a question to understand your thoughts and approach. How did you get "k2k" in your rate law for "rate=k2K[NOCl]^2/[NO]"? Since I believe that K would be a constant perhaps representing that value of "K2K", however I believ...

Marina Gollas 1A

They both mean the same thing I believe. "K-1" is "K1prime", so I would assume that they can be used interchangeably.
Also, K-1 does not mean K subtract 1, in case that was a thought. :)

Marina Gollas 1A

I am unsure if this is what you meant by your question, but my TA had explained that we use K2 to represent the K(1)/K(-1), because K2 is like the variable representing the value of what K(1)/K(-1) day is. You can keep the K(1)/K(-1) there if you would like, but K2 is there to simplify your rate int...

Marina Gollas 1A

As of now with what he stated in the syllabus, if you were to receive about 250/500 points, you will pass the class with a C-, so if you have a 75%, then that means it might average up to a B or B+, depending as the student above said, on the class average. This what is some people in the class were...

Marina Gollas 1A

Are there any useful video links you guys recommend or any online resources that break down the questions step by step?

Marina Gollas 1A

Also, what would we consider S2O3 (2-) (aq) to be? Is it a reduced? Or oxidized? Or none?

Marina Gollas 1A

In question 14.3 part a, in the following redox reaction below, it states that H2SO4- is the oxidizing agent and that Cl is the reducing agent. Why is that? Isn't Cl gaining electrons and its oxidation number is lowered from 0 to -2?
Cl2 (g) + S2O3 (2-) (aq) becomes Cl- (aq) + SO4 (2-) (aq)

Marina Gollas 1A

In basic solution, you first balance O by using H2O, then balance H by adding H2O to the side of each half-reaction that needs H , and then add OH - to the other side of the equation Thank you! So we use H20 first to try to balance the O and then next we use it to balance the H, and then what's lef...

Marina Gollas 1A

Does anyone have any tips or advice on how to prepare for the discussion test this week, or of what I should definitely know and go over? :)

Marina Gollas 1A

Is it because of the difference in the oxygen's state? Or just because we need to include H2O and OH- into it? Thank you for your help!:)

Marina Gollas 1A

How come we cannot do:
2 O(3) (aq) becomes 3 O(2) (g)
in the redox reaction:
O(3) (aq) + Br-(aq) becomes O(2) (g) + BrO(3)- (aq)
The solutions manual had stated the half reaction differently but why wouldn't this be correct?

Marina Gollas 1A

How do we know when we need to add OH- and H20 into the equations that take place in basic solutions? I know we need to add them to balance out the O's and H's in the reactants, but how do we know when to use OH- instead of H20, since my problem is that I use H2O instead of OH-. Thank you.

Marina Gollas 1A

For Question 1 Part C given on the midterm, it says "using the data given in part A, comment on the relative stability of the reactants and the products." In the data in part A that it is referring to, it says that K > Q, so the reaction would not be in equilibrium. What would have been th...

Marina Gollas 1A

I am a bit nervous for our first test in our discussion sections, and I was wondering what everyone else was doing to prepare themselves for this test, especially with the limited amount time, since I know some problems can take a while to complete. Thank you. :)

Marina Gollas 1A

Here something that another student said in this forum that helped me understand. :) "The reason that you can do an approximation where you "ignore" the x in the denominator [of the equation to find x when you complete the Ice tables], is because if the K value is smaller than 10^-3, ...

Marina Gollas 1A

Hello, Here is a link that might help you understand this concept. :) http://www.biocab.org/Irreversibility.html "When individual living organisms lose their capacity to transfer their equilibrium toward the universe, they will be in equilibrium. This is our understanding of death as it fully o...

Marina Gollas 1A

Hello,
Yes water will still be included, since only pure solids and pure liquids are excluded from the equation. Therefore, because the physical state of H2O is in a gaseous state, it should not be ignored and should be included. :)

Marina Gollas 1A

Hello, Here is a pdf that helped me understand. I hope you can open it. If this doesn't help you or you can't open it, let me know and I can explain more. :) For using Keq for Kp, it depends, since Kp asks you to include the partial pressures of the gases with it, and its asking you to solve it usin...

CHEMISTRY COMMUNITY

Search found 36 matches

Re: How to tell if its in acidic or basic

Re: Final [ENDORSED]

Re: Unique Rate quick question

Re: Solutions for Tests 1 and 2

Final Jitters

Re: Cp vs Cv

Re: Solutions for Tests 1 and 2

Unique Rate quick question

Re: Average Rate of Reaction

Writing First Order Reactions

Re: pseudo first order [ENDORSED]

Question 15.19 on 6th edition hw

Re: mmol vs mol

Direction reaction goes

pH question

Re: Balancing basic redox reactions

Initial Concentration Question

Midterm Q3

Re: k1 vs k2?

Re: k1 prime or k-1

Re: K1 vs K2

Re: Curve?

Re: Tips for Discussion Test

Re: Question 14.3 6th Edition Hw

Question 14.3 6th Edition Hw

Re: Adding OH- and H20 into reactions

Tips for Discussion Test

Re: 14.5 6th Edition Question Hw

14.5 6th Edition Question Hw

Adding OH- and H20 into reactions

Stability of reactants and products Midterm question

Studying for First Discussion Test

Re: when is x negligible

Re: Why Would Equilibrium cause death in humans?

Re: H2O

Re: Keq vs. Kc vs. Kp