# Percentage YieldWatch

#1
heyy,

If the percentage yield for a reaction is 100%, 60g of reactant A would make 80g of prodcut C. How much of reactant A is needed to make 80g of product C if the percentage yield of the reaction is only 75%?

im not entirely sure how to do this qusstion, because it is different from the traditional style percentage yield Q's.

I got 105g of reactant A is needed if the percentage yield is 75%. I figured 1% of 60g is 0.6g, therefore 75% is 45, 60+45=105g. Is this correct?

thank you!
0
9 years ago
#2
take the info from the 100% and...
Product / Reactant = Yield (grams)

then take the yield (grams) and multiply with the new percentage yield (75%)
Yield (grams) x 0.75 (percentage yield) = New Yield (grams)

now take your new yield and multiply it with the amount of product required to find the amount of reactant you need
New Yield (grams) x 80g = Reactant required (grams)

As per usual I'm sure there are normal or simpler ways of doing it but that is how I've always done it in my head.
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