CHEMISTRY COMMUNITY

Celine Hoh 2L

Just to be sure, steady state is not included in finals right?

Celine Hoh 2L

josephperez_2C wrote:Just making sure, n could never equal 0 since there is always a transfer of electrons right?

Yes I think so

Celine Hoh 2L

Tysm Lyndon! Can someone post the answer plss tyyy~

Celine Hoh 2L

Also if it is not in the syllabus, then I don’t think we need to know it.

Celine Hoh 2L

A represents the number of collisions multiplied by the frequency in which they are in the correct orientation, which gives us A the frequency factor.

Celine Hoh 2L

The entropy increases as the temperature increases, hope that helps.

Celine Hoh 2L

Can anyone explain when do we add H+ in cell diagrams?
eg.
Pt I Fe3+, Fe2+ II H+, MnO4-, Mn2+ I Pt

Celine Hoh 2L

Aurbal Popal wrote:Also, to add on to her question, you do not need to put Pt on both sides of the cell diagram if there is a solid on the other side, right?

THAT'S RIGHT

Celine Hoh 2L

I usually just remember one as an opposite of another. If something is being oxidized, then it is the reducing agent.

Celine Hoh 2L

I think we also add Pt when both species of the same kind are in the same solution, say Fe2+ and Fe3+

Celine Hoh 2L

In some of the HW problem solutions, the cell diagram shows Fe2+, Fe3+ II ..., instead of Fe2+ I Fe3+ II...
Is there a difference between using , and I ?

Celine Hoh 2L

For acidic reactions, we balance out the O by adding H2O and balance out the H by adding H+.
For basic reactions, we balance out O by adding H2O and balance out H by adding OH-.

Celine Hoh 2L

If I steal your electrons would I be legally charged?

Celine Hoh 2L

Did you know that you can cool yourself to -273.15˚C and still be 0 K?

Celine Hoh 2L

Karyn Nguyen 1K wrote:For worksheet 4, is the answer for 6a wrong? I did (3/2)(31.9 mol)(8.314 J/Kmol)(311.15 K) = 124 kJ. When I didn't convert the temperature from C to K I got 15.1 kJ which is the answer given in the key.

We don’t have to convert it to kelvin as it is change in temperature (38-0)

Celine Hoh 2L

Doe isothermal expansion ALWAYS mean reversible expansion?
Or is it possible to have isothermal, irreversible expansion as well?

Celine Hoh 2L

Quick question for Worksheet 1 ques8:

When I2 is added, neither products nor reactants is favored as I2 is a solid.
What happens when I2 is removed, does the reaction not shift too?

Celine Hoh 2L

Can someone explain how is deltaU = deltaH -p* deltaV

Celine Hoh 2L

I understand that q=0 in adiabatic situations, but why does w=Cv* deltaT? ( I thought that w is suppose to be work due to expansion of gas)

Celine Hoh 2L

In thermodynamics, a reversible process is a process whose direction can be "reversed" by inducing infinitesimal changes to some property of the system via its surroundings. Throughout the entire reversible process, the system is in thermodynamic equilibrium with its surroundings. Having b...

Celine Hoh 2L

Increasing degeneracy results in an increase in entropy of the system. This is shown by the Boltzmann equation: S=kB*ln(W), where w is the degeneracy and S is entropy. Therefore, an increase in w increases the value of S, which is entropy. This also makes sense because degeneracy is the number of wa...

Celine Hoh 2L

How do we calculate degeneracy caused by heat then?

Celine Hoh 2L

I understand that q=0 as there is no net heat change. But why isn’t W a negative value as the system has done work to expand?

Celine Hoh 2L

For the second equation S=Cln(T2/T1), is q constant then?

Celine Hoh 2L

So is it correct to say that heat is directly proportional to temperature?

Celine Hoh 2L

For last quarter there were many review sessions by both TAs and Lavelle :)

Celine Hoh 2L

I can send you the notes what’s your email?

Celine Hoh 2L

Yes drawing out the structures really worked for me

Celine Hoh 2L

When asked for Q reaction quotient, should we give in terms of pressure or concentration when the chemical equation contains both liquid and gases?

Celine Hoh 2L

And Kp is the pressure constant?

Celine Hoh 2L

I will be doing all the homework problems and going through lecture notes. GOODLUCK everybody!

Celine Hoh 2L

Anyone knows if Karen is still giving out worksheets for this class?

Celine Hoh 2L

Can we submit our hw during discussion?

Celine Hoh 2L

The K values are only affected by the change in temperature.

Celine Hoh 2L

Hi does anyone know what book is this?

CHEMICAL PRINCIPLES (LOOSE-LEAF) & SSM (NEW COPIES W/24MO SAPLING & ETEXT ACCESS)

Cause it was listed as REQUIRED in the UCLA textbook page for Chem 14B but I don’t think it’s the textbook itself coz that was listed separately.

Tqsm!

Celine Hoh 2L

Thank you! Does anyone know which other TAs or UAs post worksheets as well (besides Lyndon and Karen)?

Celine Hoh 2L

Thanks Karen for the helpful worksheets!

Celine Hoh 2L

Thanks! That was really helpful! But what about COOH though... is it one of the few exemptions?

Celine Hoh 2L

Is it safe to assume that the sequence of the chemical formula is a correct representation of the molecular structure itself?

Example: the molecular structure of CNO- is in the sequence C-N-O since the formula is CNO-

Celine Hoh 2L

When the question asks for the shape, can I just give the molecular geometry, or do I have to give both electron and molecular geometry?

Celine Hoh 2L

When the question asks for the Lewis Structure, would I be penalized if I draw out the shape instead (as the shape is just a more “advanced” version of Lewis Structure?

Celine Hoh 2L

Then does a non-wedge bond indicate that the bond goes sideways?

Celine Hoh 2L

Is it true that he will curve if the class finals average is too low?

Celine Hoh 2L

Is the CN bond usually a triple bond?

Celine Hoh 2L

I don't think it matters.

Celine Hoh 2L

I believe that they only happen in covalent bonds as ionic bonds are a complete transfer of electrons without any sharing.

Celine Hoh 2L

Yes I did some from the past sections and some on the newer topics too.

Celine Hoh 2L

Yes, for the reasons above AlCl3 is actually ionic with covalent character.

Celine Hoh 2L

Also make sure that for elements that do not have expanded d orbitals (Period 2 and above) do not exceed their octet shell.

Celine Hoh 2L

Not quite chem related but..
Why do many pre-med students want to donate their bodies to research after they die?

Because that is the only way for them to get into med school.

Celine Hoh 2L

Do we need a blue book for the test?

Celine Hoh 2L

Thank you!

Celine Hoh 2L

Btw does anyone know why is that when calculating the bond length of say BiF4, we only sum up the bond length of Bi and F, instead of summing the lengths of Bi and 4Fs?

Celine Hoh 2L

Cause the electron density is higher?

Celine Hoh 2L

605122791 wrote:But the textbook says that

Number of radial nodes
= n-1-l
Which should give us
=3-1-1
=1

Can someone explain why is the answer 2 instead of 1 please?

For b) the number of radial nodes

Celine Hoh 2L

But the textbook says that

Number of radial nodes
= n-1-l
Which should give us
=3-1-1
=1

Can someone explain why is the answer 2 instead of 1 please?

Celine Hoh 2L

The answer given in the solution manual is
a) 1 nodal plane
b) 2 radial nodes

Celine Hoh 2L

Yes, which is the Avogadro Number.

Celine Hoh 2L

Hi, I was wondering if I am allowed to use different letters when writing down a formula.. eg.for c = v x lamda can I write v = f x lamda instead? I find it confusing as some of the letters in the new equations, means a totally different thing form what I have used to learn. So, would I get penalize...

Celine Hoh 2L

Thank you for the advice!

Celine Hoh 2L

I used the Tune of Happy Birthday song!

Tera Giga Mega
Kilo Hecto Deca
Deci Centi Milli Micro
Nano Pico Hepto

Celine Hoh 2L

My TA said it’s dued by Friday midnight

Celine Hoh 2L

Thanks so much for the chart!

Celine Hoh 2L

Hi guys. May I know what’s included in our test next week?

Is it the whole of the Fundamental section, or just the sections mentioned in Outline 1?

Thanks!

Celine Hoh 2L

Is the conversion between US units and SI units given in the tests?

Thanks!

Celine Hoh 2L

Hi is it ok to not bother about significant figures in the beginning of calculations (by writing down more than the required sf.), and only round it to the correct number of sf. in the last equation?

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