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What will be the mole fraction of ethanol in a sample of spirit containing 85% ethanol by mass?
- a)0.69
- b)0.82
- c)0.85
- d)0.60
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
What will be the mole fraction of ethanol in a sample of spirit contai...
Mass of C2H5OH = 85 g
Molar mass of C2H5OH = 46 g/mol
nC2H5OH = 85/46 = 1.85 mol
Mass of water = 100 - 85 = 15 g
nH2O = 15/18 = 0.833 mol
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What will be the mole fraction of ethanol in a sample of spirit contai...
The mole fraction of a component in a mixture is defined as the ratio of the number of moles of that component to the total number of moles in the mixture. In this case, we need to determine the mole fraction of ethanol in a sample of spirit containing 85% ethanol by mass.
To solve this problem, we can use the concept of mass percent and convert it to mole fraction using the molar mass of ethanol.
Step 1: Convert mass percent to mass fraction
Given that the spirit contains 85% ethanol by mass, we can calculate the mass fraction of ethanol as follows:
Mass fraction of ethanol = mass of ethanol / total mass of the mixture
Since the total mass of the mixture is not given, we can assume a convenient value such as 100 grams.
Mass of ethanol = 85 grams (given)
Total mass of the mixture = 100 grams (assumed)
Mass fraction of ethanol = 85 grams / 100 grams = 0.85
Step 2: Convert mass fraction to mole fraction
To convert the mass fraction to mole fraction, we need to know the molar mass of ethanol. The molar mass of ethanol (C2H5OH) can be calculated as follows:
Molar mass of ethanol = (2 * atomic mass of carbon) + (6 * atomic mass of hydrogen) + atomic mass of oxygen
The atomic masses of carbon, hydrogen, and oxygen are approximately 12 g/mol, 1 g/mol, and 16 g/mol, respectively.
Molar mass of ethanol = (2 * 12 g/mol) + (6 * 1 g/mol) + 16 g/mol = 46 g/mol
Now, we can calculate the mole fraction of ethanol using the mass fraction and molar mass:
Mole fraction of ethanol = mass fraction of ethanol / (molar mass of ethanol / total molar mass of the mixture)
The total molar mass of the mixture can be calculated by considering the molar mass of all the components present. Since the composition of the mixture is not given, we can assume that ethanol is the only component present, and hence the total molar mass is equal to the molar mass of ethanol.
Total molar mass of the mixture = molar mass of ethanol = 46 g/mol
Mole fraction of ethanol = 0.85 / (46 g/mol / 46 g/mol) = 0.85
Therefore, the mole fraction of ethanol in the spirit sample is 0.85, which corresponds to option (a).
To solve this problem, we can use the concept of mass percent and convert it to mole fraction using the molar mass of ethanol.
Step 1: Convert mass percent to mass fraction
Given that the spirit contains 85% ethanol by mass, we can calculate the mass fraction of ethanol as follows:
Mass fraction of ethanol = mass of ethanol / total mass of the mixture
Since the total mass of the mixture is not given, we can assume a convenient value such as 100 grams.
Mass of ethanol = 85 grams (given)
Total mass of the mixture = 100 grams (assumed)
Mass fraction of ethanol = 85 grams / 100 grams = 0.85
Step 2: Convert mass fraction to mole fraction
To convert the mass fraction to mole fraction, we need to know the molar mass of ethanol. The molar mass of ethanol (C2H5OH) can be calculated as follows:
Molar mass of ethanol = (2 * atomic mass of carbon) + (6 * atomic mass of hydrogen) + atomic mass of oxygen
The atomic masses of carbon, hydrogen, and oxygen are approximately 12 g/mol, 1 g/mol, and 16 g/mol, respectively.
Molar mass of ethanol = (2 * 12 g/mol) + (6 * 1 g/mol) + 16 g/mol = 46 g/mol
Now, we can calculate the mole fraction of ethanol using the mass fraction and molar mass:
Mole fraction of ethanol = mass fraction of ethanol / (molar mass of ethanol / total molar mass of the mixture)
The total molar mass of the mixture can be calculated by considering the molar mass of all the components present. Since the composition of the mixture is not given, we can assume that ethanol is the only component present, and hence the total molar mass is equal to the molar mass of ethanol.
Total molar mass of the mixture = molar mass of ethanol = 46 g/mol
Mole fraction of ethanol = 0.85 / (46 g/mol / 46 g/mol) = 0.85
Therefore, the mole fraction of ethanol in the spirit sample is 0.85, which corresponds to option (a).
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What will be the mole fraction of ethanol in a sample of spirit containing 85% ethanol by mass?a)0.69b)0.82c)0.85d)0.60Correct answer is option 'A'. Can you explain this answer? for NEET 2025 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about What will be the mole fraction of ethanol in a sample of spirit containing 85% ethanol by mass?a)0.69b)0.82c)0.85d)0.60Correct answer is option 'A'. Can you explain this answer? covers all topics & solutions for NEET 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for What will be the mole fraction of ethanol in a sample of spirit containing 85% ethanol by mass?a)0.69b)0.82c)0.85d)0.60Correct answer is option 'A'. Can you explain this answer?.
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