dasda
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No idea how to start this question.

.In a reaction to form biodiesel, one mole of a vegetable oil reacts with an excess of
methanol to form two moles of an ester with molecular formula C19H34O2 and one
mole of an ester with molecular formula C19H36O2
Draw the structure of the vegetable oil showing clearly the ester links.
You should represent the hydrocarbon chains in the form CxHy where x and y are
the actual numbers of carbon and hydrogen atoms
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dasda
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charco
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charco
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(Original post by dasda)
No idea how to start this question.

.In a reaction to form biodiesel, one mole of a vegetable oil reacts with an excess of
methanol to form two moles of an ester with molecular formula C19H34O2 and one
mole of an ester with molecular formula C19H36O2
Draw the structure of the vegetable oil showing clearly the ester links.
You should represent the hydrocarbon chains in the form CxHy where x and y are
the actual numbers of carbon and hydrogen atoms
1. Do you know the general structure of a fat or oil?
2. Do you know what an ester linkage looks like?
3. Do you know how methanol/NaOH reacts with oils to form biodiesel?
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dasda
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(Original post by charco)
1. Do you know the general structure of a fat or oil?
2. Do you know what an ester linkage looks like?
3. Do you know how methanol/NaOH reacts with oils to form biodiesel?
yes. when glycerol is added to a fatty acid of R chain length
o-c=0
not sure about the last one
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charco
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(Original post by dasda)
yes. when glycerol is added to a fatty acid of R chain length
o-c=0
not sure about the last one
Taking the first one.

Yes, there is a glycerol "backbone" which has ester links to three long hydrocarbon chains.

Name:  oil_generic.png
Views: 85
Size:  18.4 KB

As there are three hydrocarbon chains they can be hydrolysed to produce up to three different long chain fatty acids.

When the oil is heated with NaOH and methanol the ester link breaks and the methanol esterifies the fatty acid. Propan-1,2,3-triol (glycerol) is also formed.

This mixture of fatty acid methyl esters is called "biodiesel.

Name:  biodiesel.png
Views: 77
Size:  36.1 KB
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dasda
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(Original post by charco)
Taking the first one.

Yes, there is a glycerol "backbone" which has ester links to three long hydrocarbon chains.

Name:  oil_generic.png
Views: 85
Size:  18.4 KB

As there are three hydrocarbon chains they can be hydrolysed to produce up to three different long chain fatty acids.

When the oil is heated with NaOH and methanol the ester link breaks and the methanol esterifies the fatty acid. Propan-1,2,3-triol (glycerol) is also formed.

This mixture of fatty acid methyl esters is called "biodiesel.

Name:  biodiesel.png
Views: 77
Size:  36.1 KB
Thanks for helping me. chemistry goat
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lhh2003
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(Original post by dasda)
No idea how to start this question.

.In a reaction to form biodiesel, one mole of a vegetable oil reacts with an excess of
methanol to form two moles of an ester with molecular formula C19H34O2 and one
mole of an ester with molecular formula C19H36O2
Draw the structure of the vegetable oil showing clearly the ester links.
You should represent the hydrocarbon chains in the form CxHy where x and y are
the actual numbers of carbon and hydrogen atoms
What year are you in and what spec ?
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dasda
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(Original post by lhh2003)
What year are you in and what spec ?
year 13. AQA.
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