Author Topic: Organic Chemistry - Percentage of Yield (Read 1212 times) Tweet Share

aakritisharma · « **on:** May 06, 2013, 07:33:46 pm »

hey guys. im having slight troubles with a question.

q. calculate the percentage yield if 5.0g of ethanol is oxidised to produce 4.8g of ethanoic acid.

now i thought that you had to go 4.8/5.0 x 100 but apparently not.
can someone explain?

clıppy · « **Reply #1 on:** May 06, 2013, 08:04:03 pm »

I'm pretty sure you need to set up an equation and see if ethanol and ethanoic acid are stoichiometrically balanced.
From what I remember to solve this kind of equation you need to find the calculated mass of the product divided by the actual mass of the product * 100 which will give you the percentage yield

kaiipoo_ · « **Reply #2 on:** May 06, 2013, 08:27:22 pm »

wouldn't the percentage yield be:

mass of product/the expected mass of product x100?

Alwin · « **Reply #3 on:** May 06, 2013, 08:38:30 pm »

Quote from: aakritisharma on May 06, 2013, 07:33:46 pm

hey guys. im having slight troubles with a question.

q. calculate the percentage yield if 5.0g of ethanol is oxidised to produce 4.8g of ethanoic acid.

now i thought that you had to go 4.8/5.0 x 100 but apparently not.
can someone explain?

$n(C_2 H_5 OH) = \frac{5.0}{2 \times 12 + 6 \times 1 + 16}$
$n(C_2 H_5 OH) = 0.108696 mol$

$\text{From stoichiometry, }n(C_2 H_5 OH) = n(CH_3 COOH)$
$n(CH_3 COOH) = 0.108696 mol$
$m(CH_3 COOH) = 0.108696 \times (2 \times 12 + 4 \times 1 + 2 \times 16)$
$m(CH_3 COOH) = 6.52176 g$

$\text{So, in theory 6.52176g of ethanoic acid should be produced.}$
$\text{percentage yield}=\frac{\text{experimental yeild}}{\text{theoretical yeild}} \times 100\%$
$\text{percentage yield}=\frac{4.8}{6.52176}\times 100\%$
$\text{percentage yield}=73.6\%$

Hopefully I haven't made some silly error somewhere in there haha. Also, if significant figures matter, round to 74% (2 sig fig)

aakritisharma · « **Reply #4 on:** May 06, 2013, 08:56:52 pm »

ohhhh. that makes so much sense. thank you soo much

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Author Topic: Organic Chemistry - Percentage of Yield (Read 1212 times) Tweet Share

aakritisharma

Organic Chemistry - Percentage of Yield

clıppy

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kaiipoo_

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Alwin

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