CHEMISTRY COMMUNITY

Arthur Mkrtchyan 2K

Hey! So it is usually a good idea to switch and celsius numbers to Kelvin as most equations refer to the temperature in Kelvin. If it is not changed, your answer will be incorrect. So yeah, it would be the safe bet to switch them over in any question. If, by any chance, you need the temperature in c...

Arthur Mkrtchyan 2K

Hey! so concentration cells work by both parts of the galvanic cell being the same type of solution. In one side, the solution is less concentrated while in another, it is higher in concentration. Because of this discrepancy, the concentration will go from the higher amount to the lower amount throu...

Arthur Mkrtchyan 2K

Hey!

So the n in the equation references the number of electrons that need to be in the balanced redox reaction. This means that both the oxidized and the reduced n values should be the same value because when added together, they need to cancel each other out

hope this helps!

Arthur Mkrtchyan 2K

Hey! So during a reaction, the catalyst would be used up as you call it. This just means that it will change its molecular structure for the reaction to occur and then get recreated at the end. If it was used during the first reaction, it will not be present in the next reaction. It will then reappe...

Arthur Mkrtchyan 2K

Hey! So im going to use the example from lecture. Take a diamond for example. It is unstable, it wants to be graphite but because the reaction happens sooooo slow, it essentially can be called stable thermodynamically. But, it is not kinetically because it still wants to go towards another form of c...

Arthur Mkrtchyan 2K

Hey!

So a salt bridge will allow for the two solutions to remain neutral when going through the reactions. This is so that there will not be a more negative side of the galvanic cell which will allow for the electrons to flow through the cell.

Arthur Mkrtchyan 2K

Hey! So the only way we can know which one will be the cathode or the anode will be based on the given E values. You will know this because the added values need to add up to a positive value. Since that is the case, the larger value will need to be flipped which will make it the oxidation reaction ...

Arthur Mkrtchyan 2K

Hey! using the zero-order reaction relationship between time and concentration we can get : [A]t=−kt+[A]0 where At is the concentration at the desired time. k is the rate of reaction. t is the time in seconds. A0 is the initial concentration. Plugging in all the variables from the given values shoul...

Arthur Mkrtchyan 2K

Hey! From what I understand about the differences between both, your statement is correct but the reaction would take such a long time to occur that we can generally say that it does not occur. Additionally, some reactions may be favorable but need to overcome an initial action potential barrier tha...

Arthur Mkrtchyan 2K

Hey!

A Salt bridge will allow the solutions of both the cathode and the anode to remain neutral while the electrons are flowing through the galvanic cell!

Arthur Mkrtchyan 2K

Hello!

I am still pretty unsure about the differences in delta g naught vs delta g. I have heard the explanation from multiple people but the idea is still unclear. Anyone have a good way of understanding it?

Thank you!

Arthur Mkrtchyan 2K

hey!

so you can go through either way to get the answer because the traditional equation accounts for both equations' reduction potentials. I personally use the numbers given from the list and plug them into the equation because it saves me from having to switch the signs in the first place.

Arthur Mkrtchyan 2K

Hey!

I also want to add that although platinum is the metal we choose to use in this class, other metals can accomplish the same goal that platinum does. This means that something like gold would accomplish the same thing because they do no oxidize as easily compared to other metals.

Arthur Mkrtchyan 2K

The salt bridge and the porous disk will allow the solutions to remain neutral so, without either a salt bridge or a porous disk, the cell would only run for a short period before the charges of the solutions would not promote the flow of electrons.

Arthur Mkrtchyan 2K

Hey! You can also understand the E value as the distance between the two reactions. Because it is an intensive property, this would mean that the distance doesn't change between the amount of E but rather both would increase or decrease at the same amount allowing the in-between distance to remain t...

Arthur Mkrtchyan 2K

Hey!

So I can mainly only answer question 1 but the switch would be using a manual system to allow the wires to connect letting the electrons flow. Similarly, the voltmeter is just a device used to measure the volts traveling through the wire after the switch is turned on.

Arthur Mkrtchyan 2K

Hey for part a, you would get the work from the equation w = -nRT ln (Vfinal/Vinital). And the n will be from the ideal gas law. So that would be n = PV/RT

For part b, you would use the equation: W = P(external) * (Delta V)

Arthur Mkrtchyan 2K

Spontaneity also implies that the reaction is favorable or will occur naturally without needing to put external work into the system. I also just like to assume that a negative H value will be exothermic and which means it is a spontaneous reaction.

Arthur Mkrtchyan 2K

Hey Guys!

I have been having a bunch of trouble with this question. From my understanding, you must add the total delta H and delta S after swapping the equations to match the final. Then, input all the numbers into the Free energy equation but my final answer isn't working.

Any thoughts?

Arthur Mkrtchyan 2K

Hey! The change in internal energy is not necessarily always positive. This just happens to be in this case because in all three situations, there is more energy coming into the system as represented by the arrows. regardless if it's done by q or w, there is a net increase in the amount of internal ...

Arthur Mkrtchyan 2K

Hey!

A heat capacity is the amount of heat required to raise the temp of an object by 1 degree C. The Specific heat capacity is the heat required to raise the temp 1 gram of a specific substance by 1 degree C.

Arthur Mkrtchyan 2K

Hey!

A positive entropy means that the reaction is endothermic, absorbing heat. In contrast, a positive entropy is exothermic, releasing heat to the environment—the concept of being spontaneous means that the reaction is exothermic or occurs without any extra energy.

Arthur Mkrtchyan 2K

Hey!

They are in there standard states when they have 1atm of pressure against them and are at 25 degrees C.

Arthur Mkrtchyan 2K

Hey, the midterm will cover topics from week 1 and 2 so most of the questions will be like the ones from class and the textbook. The achieve questions are also a good example of questions. I do not believe he has commented on whether Theory will be present.

Arthur Mkrtchyan 2K

When solving the problem, if you are solving for a base, the x value will be given to you as a the -log of pOH. In contrast, when solving for an x for an acid, the -log will come out as a pH.

Arthur Mkrtchyan 2K

Hey! The x value needs to be smaller than -10^3 to be ignored because we would be assuming that it is not large enough to affect the value of our initial concentrations.

Arthur Mkrtchyan 2K

All content through Friday week 3. So the first week's equilibrium, the acid and bases, and the first week of thermochemistry.

Arthur Mkrtchyan 2K

Hey everyone,

I was doing the chem Homework tonight and I had a quick question.

I do not understand when to use the reverse or forward reactions to get the X values in the C portion of the ICE chart.

Is it to do with the final equilibrium or more information in the question?

Thank you>

Arthur Mkrtchyan 2K

Ive heard a TA say that the midterm will be in class, but they are still unsure as well.

Arthur Mkrtchyan 2K

Hey, I find that a good way to look at it is just by using the exponent of the initial value. Since its in the form of a log, it will always turn into the pH of the solution.

Arthur Mkrtchyan 2K

Hey, Most the solutions are at the back of the text book!

Arthur Mkrtchyan 2K

I've also heard that the book has some of the answers online with step-by-step solutions, but I have been unable to find it.

Arthur Mkrtchyan 2K

Why can you never trust an atom?

They make up literally everything.

Arthur Mkrtchyan 2K

Hey Maddie,

I believe it is three times a week to get full credit and replying to other people's posts will get you credit towards the three total.

CHEMISTRY COMMUNITY

Search found 34 matches

Re: Using Degrees C versus K

Re: Concentration Cells

Re: E° Cell equation

Re: Week 10- Enzymes in equations

Re: Week 8- Kinetically vs thermodynamically stable

Re: Purpose of a salt bridge

Re: Standard reaction potential for non-Galvanic cells

Re: weeks 8-10 #8

Re: Kinetics vs thermodynamics

Re: Salt bridge

delta g naught vs delta g

Re: flipping sign of reduction potential for oxidation half-rxn

Re: Platinum Electrode

Re: No needing a salt bridge or porous disk

Re: E not value

Re: Some galvanic cell questions, voltmeter, switch and external energy

Re: Achieve week 5 and 6 (Question #3)

Re: Spontaneity

Achieve Week 5 and 6 #15

Re: Weeks 3/4 Achieve #20

Re: Defintion- Heat capacity vs. Specific heat capacity

Re: Entropy

Re: Standard States

Re: Types of Questions on Midterm 1

Re: Ka vs Kb and pH vs pOH

Re: small x-value

Re: Midterm 1

When to use a negative X value or a positive X value during the ICE chart.

Re: Class on Midterm days?

Re: Ka vs PKa

Re: Solutions for textbook problems

Re: Syllabus Problem Answers Topic is endorsed

Re: Post All Chemistry Jokes Here

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