Moles help

Help! I don’t get why they multiplied the moles of the CA by 100/25 (which is 4) because isn’t it a 1:1 ratio between the haloalkane and CA ??
I drew it and it’s a 1:1 ratio, plz help

And for this question for stage 1 I converted it into a primary alcohol and then for stage 2 I converted it into CA by heating under reflux which worked but the markscheme does CN

(edited 1 year ago)

Reply 1

George H.

The percentage yield is 25%, so for every mole of compound A you need 4 moles of (chloromethyl)benzene.

Reply 2

Alevelhelp.1

Original post by Alevelhelp.1

Help! I don’t get why they multiplied the moles of the CA by 100/25 (which is 4) because isn’t it a 1:1 ratio between the haloalkane and CA ??
I drew it and it’s a 1:1 ratio, plz help

And for this question for stage 1 I converted it into a primary alcohol and then for stage 2 I converted it into CA by heating under reflux which worked but the markscheme does CN

Original post by George H.

The percentage yield is 25%, so for every mole of compound A you need 4 moles of (chloromethyl)benzene.

Hey thanks is there an equation for this I’m so confused, because in other qs it comes up too and I need an equation 😭 or else I’ll forget and lose 6 marks

Reply 3

George H.

I'm not sure if there is an equation for this, other than Percentage Yield = Actual Yield / Theoretical Yield. Although I probably confused it by talking about moles. You can just calculate the theoretical yield of compound A by mass and then use the 1 : 1 mole ratio without doing anything else with yield. (This is the 'using mass' method in the mark scheme instead of the 'using moles' method.)

Also I think they used CN instead of converting to a primary alcohol because otherwise there would be too few carbon atoms.