Answer:
The percentage yields are as follows :
a) 64.28%
b) 58.03%
c) 69.46%
d) 79.31%
Explanation:
The percentage yield is the ratio of the actual yield of a product to the expected or theoretical yield expressed as a percentage.
Percent yield = actual yield/theoretical yield x 100%
a) from the question, expected yield is 68.3 g whilst the actual yield is 43.9 g
therefore,
Percentage yield = 43.9 g/68.3 g x 100%
= 0.64275 x 100%
= 64.28%
b) From the question, expected yield is 0.0722 mol while the actual yield is 0.0419 mol. Therefore
Percentage yield = 0.0419 /0.0722 x 100%
= 0.58033 x 100%
= 58.03%
c) A limiting reactant is the reactant is is completely used in a recation to form a product. That is, it is the reactant that is not in excess.
From the equation of the reaction :
CH3COOH + CH3CH2OH --> CH3COOCH2CH3 + H2O
1 mole of ethanol reacts with 1 mole of acetic acid to give 1 mole of ethyl acetate.
From the question, ethanol is the limiting reactant because it is not in excess. Hence,
4.29 mole of ethanol should produce 4.29 mole of ethyl acetate (expected yield).
However only 2.98 mol of ethyl acetate is produced (actual yield)
Percentage yield = 2.98mol/4.29 mol x 100%
= 0.69463 x 100%
= 69.46%
d) From the question, acetic acid is in excess hence ethanol is the limiting reactant
therefore from the equation of the reaction:
1 mole of ethanol reacts with 1 mole of acetic acid to give 1 mole of ethyl acetate.
0,58 mol of ethanol should produce 0.58 mol of ethyl acetate (expected yield)
But 0.46 mol of ethyl acetae was produced (actual yield)
Percentage yield = 0.46mol /0.58 mol x 100%
= 0.79310 x 100%
= 79.31%
