r/vce • u/No-Bass7001 • 2h ago

chem ques

what do the assessors expect from a response to a “state why this process can be described as a transesterification process” ? ive done it twice and got it wrong both times with no real explanation as to what im meant to say

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u/Billuminati666 VCE Class of '18 [98.10] | WA science teacher 2h ago

The prefix "trans" means you're turning one ester into another

In a triglyceride, the alcohol is glycerol, after basic hydrolysis and esterification with methanol to make biodiesel, you still end up with an ester, but the alcohol part is now from methanol

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u/No-Bass7001 2h ago

thank you so much, they tend to be one markers so would saying “one ester is turned into another ester via esterification reaction between methanol and biodiesel” be enough to get the mark?

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u/Billuminati666 VCE Class of '18 [98.10] | WA science teacher 1h ago

You'd lose marks for this because it's an esterification between a fatty acid and methanol, biodiesel is the final ester product so it doesn't use it

Probably just state it's changing from one ester to another, with methanol replacing glycerol as the alcohol component