CHEMISTRY COMMUNITY

san_2F

He doesn't always necessarily have to curve the class so I think if everyone does well there will be no curve.

san_2F

I think the final will be posted as an online quiz on ccle so I think you just hit submit after your done.

san_2F

I think there will be no partial credit given because it is multiple choice/ fill in the blank and they can't really assess our work. This means we have to be extra careful when working through these problems to make sure we make no mistakes.

san_2F

I think Lavelle makes the final and the midterm but I think the TA makes the tests because our TA in discussion mentioned once that each TA writes one question on the tests.

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He just sent out an email saying that we actually have 3 and a half hours to do it (11:15 - 2:45).

san_2F

I think it's either multiple choice or fill in the answer but I don't think any work will have to be shown.

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There should be a folder on the left label "FINAL" tomorrow. It opens up 11:15 and closes 2:45.

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If you are talking about kinetics and thermodynamics, I would think that he would specify which one to consider as they both represent separate things.

san_2F

The best way to study in my opinion is to do all the homework problems. In regards to review sessions, I would go to the final review sessions only for the topics that you need. I would also go to Lyndon's workshop on Monday because he goes through the topics in depth and give good practice problems.

san_2F

The one with the lower cell potential represents the oxidation half reaction and the one with the higher cell potential represents the reduction half reaction.

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The three equations for delta G.
delta G= -nFE
delta G= -RTlnK
delta G= delta H - T*delta S

You can delta the top two delta G's together.
You can also set the second equation equal to the third equation and solving for the Vant Hoff Equation.

san_2F

I would still know how to derive each of the equations as it might show up on the final.

san_2F

I remember being confused on this problem too. What I ended up doing was looking at the reduction half reactions table at Appendix 2A and going from there. I looked at the equations and found which one had O2 and H+ in one equation and O2 and OH- in another equation and manipulated to to result in t...

san_2F

What I usually do is take notes on the textbook, go through the notes from lecture, and then do all the homework problems. I also do the worksheets that my TA gives me over again.

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Test 2 is the last half of outline 4 and all of outline 5.

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in appendix 2B, the reduction values are given, so when you need oxidation values, you have to flip the sign, but rather than E cell= E cathode- E anode, it would be E cell= E cathode + E anode.

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If the E cell value is positive, the delta G is negative, and K is greater than one. If the E cell value is negative, the delta G is positive, and K is less than one.

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Appendix 2B but make sure that to manipulate the values when the reaction is flipped.

san_2F

Gibbs free energy is the best and most accurate way to tell whether a reaction is spontaneous, but using the equation delta G= delta H- T*delta S, it is possible to see what values of delta H and delta S gives a a negative delta G value.

san_2F

In most reactions, something gets oxidized and reduced. When the product of a reaction gets reduced, the reactant is the oxidizing agent. If the product of a reaction is oxidized, then the reactant is the reducing agent.

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Voltage is what drives current and it is the result of the potential difference between two electrodes.

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An electrode is a conductor in which electricity is able to travel through. In this way, electricity is able to be transferred from one place to another.

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A state function is a property that states that the path that something takes is irrelevant, the only thing that matters is the final result or final state. d

san_2F

if delta G is less than 0, that means the reaction is spontaneous. You can also think of spontaneity in terms of the equation delta G= delta H - T*Delta S in order to assess which values of delta H and delta S can produce a spontaneous reaction with a negative delta G.

san_2F

Delta G is the greatest determiner of whether a reaction will be spontaneous or not. If delta G is negative, then the reaction is spontaneous. You could also use the equation DeltaG= DeltaH- T*DeltaS, given either DeltaH or DeltaS, to see what values need to be in order to produce a spontaneous reac...

san_2F

An adiabatic reaction is when theres no heat being released or transferred into or from the system. Usually in these cases, q=0 and delta U = w

san_2F

We were given the entropy values on the midterm so I'm assuming the same will happen for the rest of the tests from here on out.

san_2F

I really hopes he curves the midterm because it was more difficult than expected. However, I wouldn't put too much hope in that because he also could easily not curve the midterm.

san_2F

I think it depends on your TA. Some TAs check at the very end of the 10 weeks while some check every week by Sunday night. My TA last quarter checked at the very end.

san_2F

I completely agree. This test was much harder than expected. I personally felt very prepared for the midterm. I did all the practice and went through them almost three times and attended the review session. Even then, I thought the test was definitely tricker than expected. I think the best way to a...

san_2F

I think the best problems are the ones at the very end (chapter exercises). They combine all the topics together really well and they are typically much harder so I think if you can do these, you're pretty prepared.

san_2F

There are three parts of to this problem. First you would have to find the change in enthalpy from the He volume change, the change in enthalpy from the Krypton volume change, and then the change in entropy from the temperature change. You would add all these entropies together to get the total.

san_2F

I would briefly look over it but in my opinion, I don't think he would put very difficult questions on that because we just went over it on the last day for like 20 minutes.

san_2F

I usually look at what they're asking me to find, write down all the equations we know that relate it, and see which equation to use based off the information given to me in the problem.

san_2F

Usually, it should give you the concentration of the reactant or some way to calculate the concentration. If not, I don't think it would be possible to assume there is a concentration when it doesn't explicitly say it in the problem so I am assuming you just put zero but not too sure.

san_2F

Also it might say something like the reaction is a free expansion in which case it would have the same effect as a reaction occurring in a vacuum.

san_2F

P= pressure, V=volume, n=moles, R=gas constant, T=temperature

san_2F

According to the internet, a photon is the only thing the human eye can see.

san_2F

I recommend only going to the review sessions for the topics you need help on. Also definitely do the homework problems because 1 out 8 of the midterm questions will come from the homework problems.

san_2F

If there are multiple equations, you should Hess's Law. If bond enthalpies are given, use the method where you calculate each of the broken bonds. If they give you enthalpies for the each of the products and reactants, use the method where you subtract the sum of reactant enthalpies from those of th...

san_2F

I first try to reorganize the equations so that they can cancel out, meaning that I put all the products on the product side and all the reactants on the reactant side. Then I see if the equations need to be multiplied by a coefficient. Then I apply the same actions to the delta Hs of each equation.

san_2F

he posted an email saying our finals were ready for pickup on Friday. However, there was some talk about how if it wasn't picked up on that day, they would be disposed of, although I'm not too sure how true that is.

san_2F

There are four main "states": solid, liquid, gas, and aqueous. In the equilibrium equation, you would include the gases and aqueous solutions, but you would exclude solids and liquids.

san_2F

I don't think there are any extra credit opportunities for 14 A or 14 B unfortunately :(

san_2F

Endothermic reactions require heat in chemical reactions and delta H is positive whereas exothermic reactions release heat in chemical reaction and delta H is negative.

san_2F

enthalpy is the amount of heat that is released or absorbed in a reaction whereas entropy is the degree of disorder. Generally, it takes energy to go from more disordered to less disordered, and energy is released when you go from less disorder to more disorder. Enthalpy and entropy are related in t...

san_2F

When they tell you to use partial pressures, you have to use the given information and plug into PV=nRT to find bars/atmospheres. When it's partial concentration, then you would just find moles over liters.

san_2F

When delta H is negative, it's exothermic and when delta H is positive, the reaction is endothermic.

san_2F

All of outline 1 and outline 2 will be on this test, which includes ICE table, Ka, Kb, and Le Chatlier's. The best way to study is to do the outline problems.

san_2F

You can use PV=nRT given moles and volume and you solve for P.

san_2F

We use ICE tables when a system was disturbed and you want to find the new equilibrium concentrations given the Kc.

san_2F

You know whether you are calculating for a base or for an acid based on whether there is OH being produced or H3O+.

san_2F

You use the Chatlier's Principle any time a reaction at equilibrium is disturbed. This includes when concentrations of either reactants are products are increased or decrease, when pressure is increased or decreased, and when temperature is increased or decreased.

san_2F

K is the fixed equilibrium constant value for a certain reaction. Q is the reaction quotient and is used when it is certain that the reaction is not at equilibrium yet. For example, if you add more products, the reaction will not be at equilibrium the moment you add more products, so you would calcu...

san_2F

ICE table only involve gases and aqueous substances. We assume the the concentrations of solids and liquids are 1.

san_2F

K is the equilibrium constant. The keyword there is constant meaning that for a certain reaction, no matter how much the initial concentration, the K value will always be the same for that reaction.

san_2F

I think it will be things from both outline one and outline two since we covered the main ideas from outline one this week.

san_2F

A neutralization reaction involves a strong acid and strong base and produces a salt and water. Both the salt and water are neutral.

san_2F

I think it was for BeO and Al2O3. These are amphoteric oxides. That's just something you know or don't because it's hard to determine that.

san_2F

I think all atoms in a molecule have hybrid orbitals and this is determined by the number of regions of electron densities there are.

san_2F

H3O+ is a tetrahedral molecule and has bond angle of 120

san_2F

yes, they are the same thing and can be used interchangeably.

san_2F

Bent and angular are the same thing and produce the same shape. However, be careful of the bond angles because are two different bond angles depending on how many electron density fields there are.

san_2F

I think what helped me most for the final was doing all the textbook problems and readings as well as really understanding the lecture notes.

san_2F

he just said that it affects normal healthy cells and either damages them or stops the replication fo them.

san_2F

I think that the grades get curved after inputing the final and assessing the final grade. Also, I have heard that he doesn't necessarily always curve the class, for example if everyone does well on the final.

san_2F

Ferrate is used when the overall complex has a negative charge and there is Iron in the complex. the same concept works for copper and cupperate.

san_2F

He supposedly curves after he determines final grades but he also doesn't necessarily always curve.

san_2F

I think we were just supposed to know the formulas for acid rain. There are two formulas invovlving SO3 and CO3 but both didn't end up showing up on the test.

san_2F

Strong Acids: HCl, HI, HBr, H2SO4, HClO4, HNO3
Strong Bases: NaOH, KOH, LiOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

san_2F

I'm pretty sure the heme complex has 4 ligands that are composed of N atoms.

san_2F

That is not necessarily true. The most stable lewis structure is when the formal charge is 0 with all the atoms in the molecules.

san_2F

yes carbon monoxide can bind to the heme complex the same way CN- binds to the heme complex

san_2F

its cumulative so it's all the main topics from the beginning of the year

san_2F

t shapes have two lone pairs and 3 bondes pairs

san_2F

a strong base produces more oh ions

san_2F

sigma bonds would be stronger

san_2F

he will be continuing from where he left off

san_2F

The greater the electronegativity difference between the elements, the stronger the bond and therefore the shorter the bond length.

san_2F

We will get test 2 back during the discussion of week 10. The final is cumulative, so it covers everything from week 1.

san_2F

Sigma bonds overlap horizontally while pi bonds overlap vertically.

san_2F

Nothing actually changes when you draw the lewis structures. You just have to acknowledge that if there's more than one bond, than one of them is sigma and the rest are pi.

san_2F

In regards to studying intermolecular forces, I would say the best way is to read the chapter in the book about them and then do practice problems.

san_2F

No they are not considered because double bonds and triple bonds are not visually represented in vsper models.

san_2F

We would only need to draw the lewis structures, not the 3D model.

san_2F

For the upcoming tests, a good way to memorize all the shapes, angles, and generla information would be to make a chart or study the pre-made charts that already exist on google.

san_2F

He spoke on this topic in my lecture when a student asked this question. He said to look at the individual molecules around it and determine each of their shape, and from there to arrange them.

san_2F

In regards to the specific molecule that he talked about during lecture, the trans molecule was when the r group was on opposite sides of the molecule and the cis molecule was when the r group was on the same side of the molecule. In addition, the trans isomer is non-polar while the cis isomer is po...

san_2F

I think it's fine to just put the number next to the atom. That's what a lot of the TAs did too during review sessions are office hours.

san_2F

Like everyone said, I think it's easier to take it after taking 14b because you already know the material so you will have a better idea of what you are going into.

san_2F

Resonance structures are all the possible lewis structures a molecule can have given its in the same position. In a resonance structure, all the bonds are the same length.

san_2F

The limit would have to do with number of electrons an entire molecule can have and the formal charges.

san_2F

We are allowed to turn in homework from chemical bonds I'm pretty sure and I think test two is week 8.

san_2F

It is not going to be on the midterm.

san_2F

The reason that Ne doesn't have higher electron affinity is because Ne already has 8 valance electrons so it doesn't want more electrons. I think the only exception is with the noble gases.

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san_2F

Only if the lewis structure can have multiple ways to draw it, then you need to draw resonance.

san_2F

If there are multiple ways to draw the same lewis structure with all the atoms in the same position, then the molecule has resonance structures.

san_2F

I would go back through your calculations and make sure that your units are what they are supposed to be. For example, make sure you're converting grams to kilograms since some of the units are in kg. Also make sure you are finding unit per atom when they give it to you in unit per mole.

san_2F

When electromagnetic radiation is emitted from the photon, the energy is released from that photon so the energy of the photon is decreased.

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