What is the mole fraction of ethanol in a mixture of 18 g water and 46 g ethanol?
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Answer and explanation
Correct answer: 0.50
Use moles rather than masses in the mole-fraction formula. Water contributes 18/18 = 1 mol, and ethanol contributes 46/46 = 1 mol, using their approximate molar masses. Total moles are 2, so ethanol mole fraction = 1/2 = 0.50. A mole fraction has no unit; it is not obtained by directly dividing 46 by the total mass.
Frequently asked questions
What is the correct answer to this question?
0.50
Why is this the correct answer?
Use moles rather than masses in the mole-fraction formula. Water contributes 18/18 = 1 mol, and ethanol contributes 46/46 = 1 mol, using their approximate molar masses. Total moles are 2, so ethanol mole fraction = 1/2 = 0.50. A mole fraction has no unit; it is not obtained by directly dividing 46 by the total mass.
Which subject and chapter does this question cover?
This is a Class 11 Chemistry question. Chapter: Chapter 01: Solutions.
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