/0's Chem Questions

[/0]

You get ethan-diol
That's the 20th MC on NEAP amirite?

Lol nah it's from heinemannnnn which NEAP were u referring to?

[TrueTears]

I've got the test, and heaps of others, cept it's on hard copy sigh...

[/0]

lol oh well

I might as well actually learn the course before i do practice exams

[/0]

You get ethan-diol
That's the 20th MC on NEAP amirite?

So anyway, if you were to oxidise this somehow, would it become ethan-dioic acid or something lol?

[dekoyl]

You get ethan-diol
That's the 20th MC on NEAP amirite?

So anyway, if you were to oxidise this somehow, would it become ethan-dioic acid or something lol?

Sorry, I'm not sure but I don't think we need to know that far.
Could be, though.
http://en.wikipedia.org/wiki/Oxalic_acid

[TrueTears]

lol oh well

I might as well actually learn the course before i do practice exams

Yes, consolidate and memorise all your facts then do the exams/tests. Or else it's a waste flipping through your book for information while doing the exams.

[chem-nerd]

Consider the following reaction pathway:
ethene -> chloroethane -> ethanol -> ethanoic acid


Is this possible? If you do addition on ethene you get 1,2-dichloroethane but this can't be used to get ethanol, can it?

yes it's possible

ethene + HCl -> chloroethane + OH^- -> ethanol + Cr₂O₇^2-/H⁺ -> ethanoic acid

[kurrymuncher]

Consider the following reaction pathway:
ethene -> chloroethane -> ethanol -> ethanoic acid


Is this possible? If you do addition on ethene you get 1,2-dichloroethane but this can't be used to get ethanol, can it?

I think you've gone straight to 1,2-dichloroethane. The chlorination happens step by step, so it would go from chloroethane first, then to 1,2-dichloroethane, if there is excess Cl2.

can anyone confirm this?

[chem-nerd]

ethene + Cl₂ goes straight to 1,2-dichloroethane

the step by step process you're thinking of is when you react ethane with Cl₂ in the presence of UV light

[kurrymuncher]

ethene + Cl₂ goes straight to 1,2-dichloroethane

the step by step process you're thinking of is when you react ethane with Cl₂ in the presence of UV light

ahhhhk my bad

[/0]

Consider the following reaction pathway:
ethene -> chloroethane -> ethanol -> ethanoic acid


Is this possible? If you do addition on ethene you get 1,2-dichloroethane but this can't be used to get ethanol, can it?

yes it's possible

ethene + HCl -> chloroethane + OH^- -> ethanol + Cr₂O₇^2-/H⁺ -> ethanoic acid

chloroethane is different from 1,2-dichloroethane though.
If you add OH you would get 2-chloroethan-1-ol
If you add two OHs you would get ethan-diol as dekoyl said
And you would not get ethanoic acid, but maybe something like oxalic acid

[chem-nerd]

^^
if you have an addition reaction between ethene and HCl you will produce 1-chloroethane
there's no need to worry about 1,2-dichloroethane in this reaction pathway

[/0]

oh my bad, I haven't seen that reaction before
thankyou

[/0]

Some /q/s:

What are the units of m/v? I thought it was just g/L but my teacher said it was 1g/100mL?
e.g. In NEAP 2009, a question asked what 32mg/L was equivalent to:




I know from elimination that the answer is C, but I don't know how to reach it directly

Also from NEAP 2009:
Selenium dioxide () is an improtant reagent in organic syntheses, as it is both an oxidant and weaaaakly acidic. In a certain reaction, 0.142g of selenium dioxide reacted with exactly 25.52mL of 0.100M chromium(II) sulfate, . In the reaction, the ions were oxidised to . To what oxidation state was the ion converted in this reaction?

/thx/!

[d0minicz]

isnt m/V mass per 100mL
soo its 3.2mg/100mL
=> 0.0032g/100mL
= 0.0032% (w/v)