1. What mass of ethanol be added to 10 kg water to have the mole fraction of ethanol equal to 0.207
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Answers
Step-by-step explanation:
Let the mass of Ethanol be 'x' g.
We need the mole fraction of ethanol to be equal to 0.2.
Thus, no. of moles of ethanol / no. of moles of ethanol + water = 0.2
First, let us calculate the no. of moles of Water.
We are given that the mass of water is 1 kg, i.e. 1000 g.
No. of moles = Gram Mass/ Molar Mass
Molar Mass of Water ( H_{2} OH
2
O ) is 18.
Thus, no. of moles = 1000/18 = 55.55
We know that the molar mass of Ethanol (C_{2} H_{5} OHC
2
H
5
OH ) is 46.
Thus,
\frac{x/46}{x/46 + 55.55}
x/46+55.55
x/46
= 0.2
x/46 = x/230 + 11.11
x/46 - x/230 = 11.11
Simplifying further, we get
5x/230 - x/230 = 11.11
4x/230 = 11.11
4x = 230 * 11.11
4x = 2555.3
x = 2555.3 / 4
x = 638.825
Thus, approximately 638.825 g of Ethanol must be added to make its mole fraction 0.2.
Answer:
Let the mass of Ethanol be 'x' g.
We need the mole fraction of ethanol to be equal to 0.2.
Thus, no. of moles of ethanol / no. of moles of ethanol + water = 0.2
First, let us calculate the no. of moles of Water.
We are given that the mass of water is 1 kg, i.e. 1000 g.
No. of moles = Gram Mass/ Molar Mass
Molar Mass of Water ( H_{2} OH
2
O ) is 18.
Thus, no. of moles = 1000/18 = 55.55
We know that the molar mass of Ethanol (C_{2} H_{5} OHC
2
H
5
OH ) is 46.
Thus,
\frac{x/46}{x/46 + 55.55}
x/46+55.55
x/46
= 0.2
x/46 = x/230 + 11.11
x/46 - x/230 = 11.11
Simplifying further, we get
5x/230 - x/230 = 11.11
4x/230 = 11.11
4x = 230 * 11.11
4x = 2555.3
x = 2555.3 / 4
x = 638.825
Thus, approximately 638.825 g of Ethanol must be added to make its mole fraction 0.2.
Step-by-step explanation:
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