CHEMISTRY COMMUNITY

JillianHood2K

Hello, I believe that i---->0 is meant to represent the notation for when the battery has max voltage at it's initial stage. This is when the hatch it still open on the circuit, and there is little to no electron flow because of the disconnect from the anode to the cathode. After the hatch is close ...

JillianHood2K

Hello, For this problem, our only hint is that the reaction produces a negative enthalpy. A negative enthalpy indicates that the reaction is exothermic; this is important because when the temperature is increased and it produces an exothermic reaction, we know that K has decreased. Therefore if K ha...

JillianHood2K

Hello, The initial voltage can also be thought of as the Ecell. The max voltage is the initial voltage because we have the hatch open on the circuit that connects the anode and cathode. If this hatch remains open that means that electrons cannot flow from the anode to cathode because there is 'break...

JillianHood2K

Hello, From I understanding, we need to add inert electrodes like Platinum when half reactions both only have products with aqueous states; this implies that there are no solids in the reaction. This problematic because solid electrodes are used as conductors that allow electron transfer ( cu, zn, a...

JillianHood2K

Hello, From my understanding, half-life reactions are indirectly influenced by temperature. k, the rate constant, is directly affected by temperature; when temperature increases, k increases as well. As we have learned, k and the half-life are inverse of each other, meaning that when the temperature...

JillianHood2K

Hello, Both sides of the equation are the same, but the right side is a bit more helpful because we can use 2.303 as tangible number to then plug in the rest of our variables. We got to the left side (w/2.303) by changing lnQ (on the right) to logQ (on the left): ln 10 = 2.302585093 OR log=1. For ex...

JillianHood2K

Hello, From I understand we need to add inert electrodes like Platinum when half reactions both only have products with aqueous states; this implies that there are no solids in the reaction. This problematic because solid electrodes are used as conductors that allow electron transfer ( cu, zn, ag, e...

JillianHood2K

Hello, Reversible reactions are an unnatural phenomena (which makes sense due to lack of spontaneity when going in the reverse), but they are more efficient than irreversible reactions. Although irreversible processes do less work, they are unable t conserve energy and cause the entropy to change mu...

JillianHood2K

Hello, Intermediate's purpose is to help reaction to create the final product. Therefore it is only a mechanism that is being utilized, but is not the purpose of the reaction, and therefore will not be in the final equation. Intermediates are created by reactants in a prior step, but will eventually...

JillianHood2K

Hey, So we can identify that this is a second order reaction by looking at the relationship between time and concentration. In this problem, the half-life first decomposes at 165s when its initial concentration is 0.264 M, and also decomposes with a half‑life of 207 s when its initial concentration ...

JillianHood2K

First you can identify the reduction potentials for both ions in the table [Mg2+(aq)+2e−⟶Mg(s) E=−2.38 V and Cu+(aq)+e−⟶Cu(s) E=+0.52 V]. Since we are dealing with a galvanic cell, we know that reaction is spontaneous and therefore the cell potential is positive. In order to finish the problem we ne...

JillianHood2K

Two equations help to understand the correlation: DeltaG0=−RTln(K) and E0cell=−DeltaG0/nF. When K is 1 (equilibrium), we know that G0 equals 0 because there is no spontaneity, DeltaG0=−RT(1)=0. Now that we see that DeltaG0 is zero when K is 1, then we can plug in 0 into our second equation and see t...

JillianHood2K

Two equations help to understand the correlation: DeltaG0=−RTln(K) and E0cell=−DeltaG0/nF. When K is 1 (equilibrium), we know that G0 equals 0 because there is no spontaneity, DeltaG0=−RT(1)=0. Now that we see that DeltaG0 is zero when K is 1, then we can plug in 0 into our second equation and see t...

JillianHood2K

Oxidizing and reducing agents are a bit confusing because they are doing/ causing their namesakes but the end result for them is the opposite. Oxidizing agents oxidize other molecules by accepting more electrons; because they accept electrons in order to cause oxidation, they end up with a more nega...

JillianHood2K

Using the Nerst equation, first we have to identify the reduction reaction of SHE, which is 2H+(aq)+2e−↽−−⇀H2(g). Knowing that the potential reaction under the standard conditions is 0V, we know that E naught is also 0V. We also know that since 2 electrons are being transferred, that the n in the Ne...

JillianHood2K

I believe it is because as we add heat to the gas, it begins to expand which means that we have to take volume into account. I hope this made sense and helped!

JillianHood2K

You have to find the relation between Cv and Cp to answer the question. Since Cv=Cp-R the Cv=5/2. Now you just multiply the #moles* Cv * R constant* Temp change. Hope this helps!

JillianHood2K

Hey, I was wondering the same thing but I'm assuming it will be weeks 3-6, maybe 3-5 if he is feeling merciful. Good luck!

JillianHood2K

Chemists are so happy in the lab because they're in their element.

JillianHood2K

Thought this was pretty interesting and relevant given the past couple of years:
https://www.sciencedaily.com/releases/2 ... 124418.htm

JillianHood2K

Thought this was pretty interesting and relevant given the past couple of years:
https://www.sciencedaily.com/releases/2 ... 124418.htm

JillianHood2K

Hey, I was working through the practice problems for the textbook, but I can't find the answer key. Please let me know if anyone knows where to find it, thanks!

JillianHood2K

Hello, does anyone know how many questions will be on the exam and how long we have to complete it? thanks!

JillianHood2K

Hey, So for question 7, as an example, they give us the Ka but say that the salt acts as weak base. This tells us that we need to figure out the Kb by using the Kw expression (ka * kb= 10^-14)\. Once you figure out kb then the equation proceeds like normal: use the ice table, solve for x, and then u...

JillianHood2K

hey, so it will be in person on Wednesday at 6pm, but we need respondus downloaded because we are taking the exam on our computers. We will be able to write our equations on pen and paper, btu we submit answers online. Good luck!

JillianHood2K

I think it depends on each question, and you look for how many sfs are present in the given numbers.

JillianHood2K

Hi, he posts the lectures on bruinlearn after class. All the lectures are under the tab labeled UCLA Media Reserves. Hope this helps!

JillianHood2K

Hey, I was wondering if anyone knew what day our midterms and final are? Thanks!

JillianHood2K

If solids and liquids are given in a reaction they sould NOT be used when solving the K equation. Only gases and aqueous solutions should be solved in K equations.

JillianHood2K

The concentration would change if the volume is changed because concentration is partially dependent on the amount of volume. Now that the concentration has changed the reaction can not be equilibrium any longer and we would have to use Q to solve for the reaction.

JillianHood2K

K, Kc, and Kp are all used for the same equation (P/R), but they just specify what units the products and reactants used.

CHEMISTRY COMMUNITY

Search found 31 matches

Re: what does i-> 0 represent

Re: Week 1 Achieve, question # 8

Re: Initial Voltage

Re: Inert Electrodes

Re: Half Lives and Temperature

Re: Nernst equation

Re: Inert Electrode

Re: Irreversible vs. Reversible Expansion

Re: intermediates

Re: achieve hw #12

Re: Achieve week 7/8 Q9

Re: Standard Cell Potential and Free Energy

Re: Standard Cell Potential and Free Energy

Re: Oxidizing vs Reducing Agents

Re: Achieve Week 7/8 #17

Re: Achieve Weeks 3 & 4: Delta U and q

Re: Achieve weeks 3-4 #17

Re: Midterm 2

Re: Post All Chemistry Jokes Here

Re: Chemistry News

Re: Chemistry News

Textbook Answer Key

Exam Logistics

Re: Achieve Week 2 Question 7 and 8

Re: Midterm

Re: Sig Figs number [ENDORSED]

Re: In Person Friday's For Online Students

Exam Dates

Re: Homogeneous and Heterogenous Reactions

Re: changes in concentration

Re: Kc vs Kp vs K