Short Answer Solutions

[thushan]

Any mistakes, let me know!

https://word.office.live.com/wv/WordView.aspx?FBsrc=https%3A%2F%2Fwww.facebook.com%2Fattachments%2Ffile_preview.php%3Fid%3D1686959474884652%26time%3D1447131174%26metadata&access_token=1090179778%3AAVI6nb8tk3Oa6crDa7pOcgyFY-4o5DkWhp6Gak_9FNkBwg&title=%28680208047%29+2015+Chemistry+Exam+%282%29.docx

EDITS:
MPa question - should be 6.9 kg, my mistake.

With the Br2 question, my mistake too - Q should be 0.2.

[zsteve]

thanks so much! *stops doing physics paper*
Ouch - got the ester question wrong (downfield septet)

Out of interest - for the methyl ester question (got that right, but still curious), is it valid to compare peak areas between different substances? I mean, you can't compare between different substances, it's only proportional to concentration for the same substance. Is it right to assume that they are comparable because the molecules are so big?

[jyce]

In regards to Section B Question 7b: shouldn't Q = 0.2 M^-1?
You squared the concentration of Br₂, but it's coefficient in the equation is 1.

[mtse]

For some reason I can't open the sample answers (all I see is the first two pages of the exam over and over again). Help anyone? Thank you

Edit: Nvm. It's working now

[boingo]

I think with the last part of Q10, you need to multiply the 70 by 1000? because 1 Mpa=1000kPa?

[odeaa]

I think with the last part of Q10, you need to multiply the 70 by 1000? because 1 Mpa=1000kPa?

the 1000 cancelled out the kilograms, so it works out anyway

[thushan]

MPa question - should be 6.9 kg, my mistake.

With the Br2 question, my mistake too - Q should be 0.2.

[boingo]

the 1000 cancelled out the kilograms, so it works out anyway

Ah makes sense. He left his answer in kgs. All cool (y)

[Splash-Tackle-Flail]

I got 0.0019blah blah for Question 2ci and ii. But I swear I did the same thing as you (can't remember ahh)- could you explain please how to do it?

[warya]

who else drew butan-2-ol like an idiot ahhhhhhahahahhah

[JaidynM]

thanks so much! *stops doing physics paper*
Ouch - got the ester question wrong (downfield septet)

Out of interest - for the methyl ester question (got that right, but still curious), is it valid to compare peak areas between different substances? I mean, you can't compare between different substances, it's only proportional to concentration for the same substance. Is it right to assume that they are comparable because the molecules are so big?

I think it's because the relevant chromatography technique will have a similar sensitivity to similar compounds. So although you can't really compare between different compounds, two large methyl esters that are pretty much the same structurally are similar enough that their peak areas can be compared.

[sunshine98]

Isnt the oxygen in the thermochemical equation supposed to be 49/2 not 51/2 , or is it just me?

[zsteve]

In Q4, I read absorbance as 10.0 mmol/L (extra sig fig, but the graph doesn't say anything) (simply my interpretation of the graph). Is this acceptable?

[Splash-Tackle-Flail]

Isnt the oxygen in the thermochemical equation supposed to be 49/2 not 51/2 , or is it just me?

yea i got 49/2, I think you get 51/2 if you forget the two oxygens in the hydrocarbon thing

[dankfrank420]

For the isomer of butanol, do you have to draw butan-1-ol or could you draw something else?

Could glycerol be found in the aqueous layer in question 9a?