CHEMISTRY COMMUNITY

Alyssa Parry Disc 1H

Depending on the order of the reaction which should be given, you would use the integral of the rate law equation.

Alyssa Parry Disc 1H

When you want to find k, A, Ea, or sometimes T, when you have other parameters. But since there are many forms of the equation it can be hard to tell

Alyssa Parry Disc 1H

I think that you only have to sublimize when you have only two molecules in different states and nothing else

Alyssa Parry Disc 1H

Or you could think of it like this units of k=M^(1-n).s-1 where n is the order.

Alyssa Parry Disc 1H

I'm not quite sure why they don't use that specifically but I am pretty sure that coefficients don't really affect anything

Alyssa Parry Disc 1H

We are given the rate law and all we are doing is proving that it is correct and logical and no the second order has nothing to do with the coefficient 2

Alyssa Parry Disc 1H

Basically you take the rate law (rate=k[a] for first order) and the units of rate are always mol.L-1.s-1 and then the units of concentration are always mol.L-1 and then you plug those in to find units of k, which would be s-1.

Alyssa Parry Disc 1H

Can you clarify what you mean by how the answers are constructed?

Alyssa Parry Disc 1H

E naught is standard reduction potential and E is the potential of a reaction

Alyssa Parry Disc 1H

You just look in the back of the book in Appendix 2B and then find the best half reaction with Mno4- and the best half reaction for Fe2+

Alyssa Parry Disc 1H

I think it is because Tl+ is more stable than Tl3+

Alyssa Parry Disc 1H

I think its just based off whats in Appendix 2B

Alyssa Parry Disc 1H

You have to look at the other molecules and their typical oxidation states like in this one you would look at the oxidation states of H and O, Usually +1 and -2 respectively and then look at the total charge of both molecules, I think in this case its 0 for both and then you just do algebra. Like fo...

Alyssa Parry Disc 1H

I think just the ones for group 1(+1), group 2(+2), group 6(-2), group 7(-1), etc.

Alyssa Parry Disc 1H

I think that was just for Chem 14A

Alyssa Parry Disc 1H

I think we should be getting it

Alyssa Parry Disc 1H

Why is the deltaH fusion negative though? I don't understand

Alyssa Parry Disc 1H

Is this formula ever negative?

Alyssa Parry Disc 1H

This is because reversible reactions basically means it is at equilibrium so that means that Stotal would be 0.

Alyssa Parry Disc 1H

Im pretty sure that that is just a typo in the solutions manual and it should have an l because if you look at the value they use it is the value for H20(l) not (aq)

Alyssa Parry Disc 1H

In this question they ask you to calculate deltaG but they give no temperature and the solutions manual uses 298K so does that mean we are supposed to use room temperature when T is not given?

Alyssa Parry Disc 1H

This is because you are calculating the two things, the ice that melts into water and the liquid water that you started with, separately.

Alyssa Parry Disc 1H

I'm pretty sure it increases the amount of energy

Alyssa Parry Disc 1H

Why when calculating bond enthalpies are reactants positive and products negative but then when calculating standard enthalpies of formation are reactants negative and products positive?

Alyssa Parry Disc 1H

For question 8.99 can someone tell my why in the last step the solutions manual uses 800g, like where did that come from?

Alyssa Parry Disc 1H

In this question why are there no h-c bonds broken or formed? Are they just unimportant?

Alyssa Parry Disc 1H

This because the reaction enthalpies are give in simply kJ, but they are meant for one mole of the reaction so for this question you need to acknowledge the units to get kJ in the answer

Alyssa Parry Disc 1H

This is because there are more atoms which makes it possible to have more possible bond vibrations that can absorb added heat.

Alyssa Parry Disc 1H

What are bond enthalpies and what are they used for?

Alyssa Parry Disc 1H

In the answer for 8.31a, what is the significance of Cp,m=5/2R. Is that supposed to be the molar heat capacity? If so, how would we calculate that using that formula?

Alyssa Parry Disc 1H

Do lone pairs affect polarization? If so which way is the dipole towards the lone pair or towards the bonding atom?

Alyssa Parry Disc 1H

Ligands are pretty much only put in order in alphabetical order although I am not sure about the prefixes bis, tris, etc.

Alyssa Parry Disc 1H

I'm pretty sure since there weren't a lot if any problems about Molecular Orbital Theory that we don't need to know it for the test.

Alyssa Parry Disc 1H

How can you figure out whether or not a command is bidentate, tridentate, polydentate, etc.? Or do you just have to memorize them?

Alyssa Parry Disc 1H

On the first module it asks two different questions on whether it shifts to the right or lies to the right and with left also. Is there a difference between saying shifts or lies to the right/left? If so, which is better?

Alyssa Parry Disc 1H

Because the angle is large between the equatorial atoms at 120 degrees while if it were on the axial it would only be 90 degrees between the axial atom and the equatorial atom

Alyssa Parry Disc 1H

I believe that it means there are two oxalates

Alyssa Parry Disc 1H

You have to take into account the regions of electron density when hybridizing orbitals which includes the lone pairs so you have to take them into account

Alyssa Parry Disc 1H

When writing the hybridization in what order does it go in? I've seen it as both sp2d and as dsp2. Which is best or which is correct?

Alyssa Parry Disc 1H

For question 4.81 which asks to predict the composition of the hybrid orbitals used by each B and N atom for the compound borazine, will we have to know this for the test? I don't think Lavelle went over this in class so I want to make sure it's not super important.

Alyssa Parry Disc 1H

This is because sulfur has a lower ionization energy than nitrogen and fluorine

Alyssa Parry Disc 1H

In the review session today why does the Lewis Structure have three double bonds for three of the O atoms instead of just one bond for each O atom?

Alyssa Parry Disc 1H

Covalent bonds are stronger in terms of intermolecular bonds, but in terms of intramolecular bonds ionic bonds are stronger. This is because in terms of intermolecular bonds, there is only electrostatic energy holding the atoms together but with covalent bonds the atoms are sharing electrons which m...

Alyssa Parry Disc 1H

Q: I heard oxygen And magnesium were going out
A: And I was like OMg

Alyssa Parry Disc 1H

Q: Why do chemists like nitrates so much?
A: They're cheaper than day rates.

Alyssa Parry Disc 1H

This is because like copper right above it, the half full or full d subshells (4d5 or 4d10) are more stable than 4d4 or 4d9 so the electron is in the 4d subshell rather than the 5s subshell

Alyssa Parry Disc 1H

For the upcoming test 3, what exactly do we need to know about Shrodinger's Equation? Is it just concepts or is there calculations we need to know?

Alyssa Parry Disc 1H

Yes because in the example he gave in class he specified what type of p orbitals. So I think we will need to do that for the test.

Alyssa Parry Disc 1H

Yes, for example if the energy of the incoming photon matches the energy difference between n=3 and n=1 then the electron will move to n=1, but if the energy of the incoming photon matches the energy difference between n=3 and n=2 then the electron will only move to n=2.

Alyssa Parry Disc 1H

I am just a little bit confused on when to use DeBroglie's equation. I'm not quite sure when to use it, so can someone please explain it to me?

Alyssa Parry Disc 1H

I was curious as to why we don't use the Rydberg equation from the book and why it is better to use -hR/n^2? Doesn't it kind of do the same thing?

Alyssa Parry Disc 1H

The way I solved this problem was finding the limiting reactant in the first reaction (P4) and then using the leftover O2 and the amount of P406 as the amounts given for the second reactant and then I was able to find the limiting reactant for the formation of P4O10. I did this because the question ...

Alyssa Parry Disc 1H

Hi I also had a question about this problem too. In the answer after they divided each substance by 0.0113 mmol, they then multiplied by 6. I understand that you have to multiply by a whole number to get whole number ratios, but I am very confused why they used 6 and not another number like 5. If so...

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