ocr f332 mole ratio

http://www.ocr.org.uk/download/pp_11_jan/ocr_61494_pp_11_jan_gce_f332.pdf

3a.

I got the moles of each, now what? I don't really understand what the markscheme says..

Thanks

Also, for 1g in making propene into a bromoalkane, why is uv radiation necessary? i thought you just neded the aqeous solution of chlorine (hcl) in a seperating funnel, decanting the upper layer off, shaking with sodium hydrogencarbonate, adding anyhdrous sodium sulfate and distilling for purity? none of this was in the mark scheme, but uv radiation and chlorine was...

(edited 11 years ago)

Reply 1

lollage123

in fact upon counting, propene to compound a means HCL was used, due to an extra hydrogen atom, therefore it must have been HCL.. why does the mark scheme say chlorine and UV?or have i gone wrong?

Reply 2

s.aley

Mr KCl= 74.6 Mr NaCl = 58.5

in 100g,

KCl = (1/3)100g NaCl = (2/3)100g

this in moles is

KCl = 100/(3*74.6) NaCl = 200/(3*58.5)

in terms of K and Na is the same cause there is one mole of each in the corresponding compounds

so K:Na = 100/(3*74.6) : 200/(3*58.5)

ok im gonna edit this cause it might look confusing:

for every 1 gram of KCl there will be 2 grams of NaCl (because its two thirds is twice as much as one third)

so this in moles will be

(moles of kcl) 1/74.6 (moles of nacl) 2/58.5

1 mole nacl has 1 mole na, 1 mole kcl has 1 mole k
so the ratio for k:na doesnt change

(edited 11 years ago)

Reply 3

s.aley