Mass Balance Help?

[匿名]

2016-09-10 8:51 pm

1000 kg of a 20percent by wt mixture of acetone in water is separated by multistage batch distillation. The top product (distillate) contains 95percent by wt. acetone and the still contains 2percent acetone. Calculate the amount of distillate.

回答 (1)

Roger the Mole

2016-09-10 9:25 pm

✔ 最佳答案

20% of 1000 kg = 200 kg acetone
1000 kg total - 200 kg acetone = 800 kg water
Let z be the mass of water in the distillate.
Then 800-z is the mass of water in the still.
Let y be the mass of acetone in the distillate.
Then 200-y is the mass of acetone in the still.
(All masses above and below measured in kilograms.)
Given:
y / (y + z) = 0.95 [distillate]
(200 - y) / (200 - y + 800 - z) = 0.02 [still]
Solve these two simultaneous equations algebraically:
y ≈ 183.871 kg and z ≈ 9.67742 kg
So the mass of distillate = y + z:
183.87 kg + 9.677 kg = 194 kg total distillate

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