stonecold's chem questions :)

[stonecold]

(2.998 × 10^8 ms–1) / (4.347 × 10^–6 m) = 6.897 × 10^14 Hz = 6.9 × 10^14 Hz

someone please tell me the textbook is wrong, and that the answer should read to the power of 13...

[superflya]

calculator says 6.897 x 10^13

[the.watchman]

calculator says 6.897 x 10^13

Definitely looks like it!
The power should be 13, not 14

[stonecold]

thanks.

also, this question for propan-1-ol only please.

a)   the number of different types or environments of protons in the molecule
b)   the number of peaks into which the signal due to the proton marked with (*) would be split

i get a)3  and b)4

[chem-nerd]

for propan-1-ol

a) 4 different proton environments (the two CH₂ groups are not equivalent)

b) technically the signal would be split into 12 peaks ( (3+1) x (2+1) ) because the neighbouring CH₃ and CH₂ protons are not equivalent. However, there will be some overlapping of peak splits so all 12 will probably not be clearly defined.

[stonecold]

for b) the book says 1 with a hash next to it...the other two didn't have hashes, so i don't know what that means lol...
nmr is sooo complicated

[vexx]

thanks.

also, this question for propan-1-ol only please.

a)   the number of different types or environments of protons in the molecule
b)   the number of peaks into which the signal due to the proton marked with (*) would be split

i get a)3  and b)4

yeah there are four hydrogen environments

and so for b)
it is asking how many of those four 'peak's or environments are affected (split) by the presence of that *hydrogen.

i drew this quickly and saw that only the *hydrogen is connected to a carbon that links to two other carbons and one hydrogen. so the only neighbouring hydrogens it has, is the one opposite the carbon it is attached to.

therefore, for that single neighbouring hydrogen: to find the number of peaks it has, it would be split due to presence of that *hydrogen.

so the answer is 1, as no other hydrogens are affected from the "signal" the proton *hydrogen produces.
does that make sense?

hope this is right lol i haven't looked into this specific stuff for about 2 months, so my wording may be a little sketchy.

[stonecold]

yeah, i get your reasoning.
thanks.

but why does this logic not apply for the other two?

[vexx]

yeah, i get your reasoning.
thanks.

but why does this logic not apply for the other two?

what are the other two?

[chem-nerd]

for b) the book says 1 with a hash next to it...the other two didn't have hashes, so i don't know what that means lol...
nmr is sooo complicated

the # is next to the tartaric acid answer
and either the answer for propan-1-ol (b) is incorrect or they've put the asterisk over the wrong proton

and so for b)
it is asking how many of those four 'peak's or environments are affected (split) by the presence of that *hydrogen.

i drew this quickly and saw that only the *hydrogen is connected to a carbon that links to two other carbons and one hydrogen. so the only neighbouring hydrogens it has, is the one opposite the carbon it is attached to.

therefore, for that single neighbouring hydrogen: to find the number of peaks it has, it would be split due to presence of that *hydrogen.

so the answer is 1, as no other hydrogens are affected from the "signal" the proton *hydrogen produces.
does that make sense?

hope this is right lol i haven't looked into this specific stuff for about 2 months, so my wording may be a little sketchy.

^^ vexx I think you've misinterpreted the question here

[stonecold]

okay, thanks

how do you go about writing this equation.
i've ogt no idea how the book gets its answer:

Blood alcohol content can also be determined by using a fuel
cell. Write half equations describing the oxidation of ethanol
and reduction of oxygen in an acidic electrolyte.

[Mao]

Unit 4 material

[stonecold]

Okay thanks Mao.  Stupid text put that question in AoS 1 for Unit 3.

[vexx]

^^ vexx I think you've misinterpreted the question here

ah eek, the question is really badly worded then as i thought it read something else.. haha

[stonecold]

^ yeah that question really stunk!

(CH3)₂CHCH₂CH₃

that is 2-methylbutane yeah?

book says it is 1-methylbutane, which correct me if I am wrong, is not possible?

edit: also, is this (CH₃)₂C=CH₂  2-methyl-prop-1-ene ?