CHEMISTRY COMMUNITY

Doris Cho 1D

Draw the Lewis structure of boric acid, B(OH)3. (a) Is resonance important for its description? (b) The proton transfer equilibrium for boric acid is given in a footnote to Table 6C.1. In that reaction does boric acid act as a Lewis acid, a Lewis base, or neither? Justify your answer by using Lewis ...

Doris Cho 1D

Decide whether an aqueous solution of each of the follow- ing salts has a pH equal to, greater than, or less than 7.
e) AlCl3?
can someone explain why this is acidic and the chemical equation.

Doris Cho 1D

what exactly did we need to know about the difference between clean and dirty coal?

Doris Cho 1D

Which is the stronger base, the hypobromite ion, BrO2, or morphine, C17H19O3N? Justify your answer.

what are you supposed to be looking for to determine which is the stronger base?

Doris Cho 1D

i'm just checking to make sure i did it right because i think there are some problems with the solutions manual, but for (iv) does:
[H30+] = 5.62x10^-15
[OH-]=1.78
pH=14.25
pOH=.75 ?

also, for (iii), does [OH-] = 5.62 x 10^-14 or -15?

Doris Cho 1D

Suggest an explanation for the different strengths of (a) acetic acid and trichloroacetic acid; (b) acetic acid and formic acid.

can someone explain what you should think about when answering this?

Doris Cho 1D

what are qualities you can identify in a base to know if it's very strong or weak?

Doris Cho 1D

How can you tell if something is a lewis acid or base based on the lewis structure?

Doris Cho 1D

Write the chemical equations of the two proton transfer equilibria that demonstrate the amphiprotic character of (a) HCO 2; (b) HPO4^2- . Identify the conjugate acid–base pairs in each case.

can someone explain how I would start off by doing this?

Doris Cho 1D

Which of the following can be classified as reactions between Brønsted acids and bases? For those that can be so classified, identify the acid and the base. (Hint: It might help to write the net ionic equations.) (a) NHI(aq)1HO(l)SNH(aq)1HO1(aq)1I2(aq) (b) NHI(s)SNH(g)1HI(g) 43 (c) CH3COOH(aq)1NH3(a...

Doris Cho 1D

I'm not sure about either, but considering the final is going to be 3 hours instead of 2, probably a few more than the midterm.

Doris Cho 1D

how can you determine if an isomer is able to for chelating complexes?

Doris Cho 1D

I'm still not quite sure the concept of cisplatin, like what do we need to know about it? Can someone give me a brief explanation of its importance?

Doris Cho 1D

How do you determine if a ligand can be polydentate?

Doris Cho 1D

Yes, I believe the final should include the biological functions of transition metals

Doris Cho 1D

for c. BH4-, where does the one lone pair come from to make the hybridization of B sp3d?

Doris Cho 1D

Can someone explain letter b to me?

Doris Cho 1D

how can you tell if a molecule is nonpolar or polar based on its lewis structure? or can you only tell from the difference in electronegativity?

Doris Cho 1D

how do you know the bond angle would be about 107 degrees instead of about (slightly less than) 109.5 degrees?

Doris Cho 1D

for a. does it matter if, for the lewis structure, the hydrogens are drawn vertically above and below the carbon atoms instead of diagonally like how it is in the book?

Doris Cho 1D

for d, why would XeO3 not be considered T-shaped instead of trigonal pyramidal?

Doris Cho 1D

for letter b (how many different OSCI bond angles are there?) I understand what the answer is saying, but I don't get how it answers the question, can someone explain it to me?

Doris Cho 1D

how are the two related, how would a dipole moment affect intermolecular forces?

Doris Cho 1D

Which of the following molecules are likely to form hydrogen bonds: (a) PH3; (b) HBr; (c) C2H4; (d) HNO2?

what should i be looking at first to answer this?

Doris Cho 1D

For which of the following molecules will dipole–dipole interactions be important: (a) CH4; (b) CH3Cl; (c) CH2Cl2; (d) CHCl3; (e) CCl4?

what am i supposed to be looking at when determining this?

Doris Cho 1D

Identify the types of attractive intermolecular interactions that might arise between molecules of each of the following substances: (a) NH2OH; (b) CBr4; (c) H2SeO4; (d) SO2.

i'm not sure what to really look at first when finding the different types...

Doris Cho 1D

I still don't quite understand the difference between the two, can someone explain it to me?

Doris Cho 1D

Can someone explain parts a and b for me? I just don't understand conceptually

Doris Cho 1D

how would you show that a molecule is ionically bonded or covalently bonded through a lewis structure?

Doris Cho 1D

when it asks which structure most likely to, what does it mean? "most likely to...?" I know which it's the one where the formal charges are closest to zero but what exactly and i trying to find?

Doris Cho 1D

for the material that's covered on the midterm, is it everything in chemical bonds too? or does it only go up to a certain point in chem bonds?

Doris Cho 1D

for part b, why are p and k3 separated instead of bonded together?

Doris Cho 1D

Can someone explain to me how to even get the resonance structure from a lewis structure? for example, NH4+, what is it supposed to look like?

Doris Cho 1D

I just don't understand how to go about c.

"How many values of ml are allowed for an electron in a 3p subshell?"

Doris Cho 1D

Can someone explain just c and d?

Doris Cho 1D

How many orbitals can have the following quantum numbersinanatom:(a) n=2,l=1;(b)n=4,l=2,ml=-2; (c)n=2;(d)n=3,l=2,ml = +1?

How would you go about doing this?

Doris Cho 1D

I'm just need some clarification because I think I understand but I'm not sure. is the magnetic quantum # for each orbital basically the + and - values of whatever l is and 0?
For example: is 5f values -3,-2,-1,0,+1,+2,+3 because l=3?

Doris Cho 1D

Is this something you just have to know, how do you know how many orbitals are present when l = a certain number?

Doris Cho 1D

i was kind of confused from friday's lecture but, for example, how do you get that Carbon is 1s^2 2s^2 2p^2 or that Sc is 3d^1 4s^2?

Doris Cho 1D

we'll probably have to know the more used ones like from microwaves to x-rays...

Doris Cho 1D

so the speed is + or - 5 m/s so how do you know to multiply the mass (8.00 kg) by 10 instead of just 5 m/s?

Doris Cho 1D

for parts b and c where do you find out that to convert the atoms to joules it's a multiplication of 3.37x10^-19? I can't find that conversion anywhere...

Doris Cho 1D

I peeked at the solutions manual and was confused where the 64 J came from to find the number of protons. I found the 4.733 x 10^-19 J/photon^-1 but how do you know to divide 64 J by it? also, just for clarification, when you find the amount of moles, is Avogadro's number used because photons are ac...

Doris Cho 1D

Not sure what the question is even asking... I understand what the answer is saying but I don't understand the question (?) if anyone knows what I mean...

Doris Cho 1D

I matched up the right radiation to each event but I only figured out the 3.3 x 10^-19 J to microwaves because of process of elimination... does it need to be converted to Hz or nm for me to see that it goes with microwaves?

Doris Cho 1D

thought I knew how to start this problem, looked at the solutions manual and was very wrong. How do you know to start looking for the mass of oxygen from the first reaction if it's asking for the limiting reactant of the second formation (P4O10)? Are you even supposed to do anything with the P4O10? ...

Doris Cho 1D

I've worked out most of the problem, but when I look at the solutions manual, I'm confused where they got the mole ratio of 2 mol NaOH over 1 mol Cu(NO3)2? so when you're finding them oles of NaOH required to react with .04 mol Cu(NO3)2 in part B, how do you know there's 2 mols of NaOH? also is some...

Doris Cho 1D

Solve this exercise without using a calculator. The reaction 6 ClO2(g) 1 2 BrF3(l) -> 6 ClO2F(s) 1 Br2(l) is carried out with 12 mol ClO2 and 5 mol BrF3. (a) Identify the excess reactant. (b) Estimate how many moles of each product will be produced and how many moles of the excess reactant will rema...

Doris Cho 1D

Not really sure where to even start for the problem, but would you use the formula n=m/M and the m would be = to the 70 g.mol-1 and replace the M with the atomic mass of gallium, then multiply by Avogadro's number to the find the number of moles and then do something similar for finding the amount o...

Doris Cho 1D

I'm also confused by this, but it may have to do with the work that's done for the problem? so when you divide the 25.92 x 10^-3 by 20.01 mol and get 1.30 x 10^-3 the answer for this part (1.30 x 10^-3) has 3 sig figs, which is the least amount of sig figs in part, so this might be why the final ans...

Doris Cho 1D

the formula unit is basically the empirical formula, so it's the lowest whole number ratio of ions in an ionic compound.
we divide 5.15 by the total mass of Epsom salts because of the formula of finding the number of moles, n=m/M, then, in this case, you multiply by Avogadro's number.

Doris Cho 1D

Would it be fine if my final answer is off by a little? my rounding gets mixed up in the middle when I do problems and I end up with an answer that's a thousandth/hundredth of a number too high/low... For example in the problem F1, the mass I get for hydrogen ends up as 10.58% but the answer says it...

Doris Cho 1D

I'm having trouble determining how many sig figs should be in my final answer and there aren't any numbers in the problem to tell me the least amount of sig figs to use. For example, in F5, I rounded the percentages to 4 sig figs but the answers have either 4 or 5 sig figs... is it just a trial and ...

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