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# percentage yield Watch

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1. an ester is hydrolysed as shown:
RCOOR + h20 ----> RCOOH + ROH
what is percentage yield of RCOOH when 0.5g of RCOOH (mr=100) is obtained from 1g of RCOOR (mr=150)?

please can someone explain how to answer this
2. (Original post by hanakm)
an ester is hydrolysed as shown:
RCOOR + h20 ----> RCOOH + ROH
what is percentage yield of RCOOH when 0.5g of RCOOH (mr=100) is obtained from 1g of RCOOR (mr=150)?

please can someone explain how to answer this
all you need t know is that

n = m / Mr

n is number of moles
m is mass
Mr is relative molecular mass

The first thing to work out is the maximum amount of product that could be made.
Moles of starting material is 1gram/ 150grams per mole = 0.00666 moles.

the reaction converts 1 mole of starting material to 1 mole of products so 0.00666 moles is the maximum amount of product we could obtain.

0.00666 moles of product is equivalent to 0.00666moles x 100 grams per mole = 0.666 grams

We actually only make 0.5grams so the percentage yield is
(0.5/0.666)x100 = 75% yield

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