Textbook Question
A solution is made containing 20.8 g of phenol (C6H5OH) in 425 g of ethanol (CH3CH2OH). Calculate (a) the mole fraction of phenol,
14. Solutions
Mole Fraction of Solutions
Multiple Choice
Calculate the mole fraction of sucrose (molar mass = 342.3 g/mol) in an aqueous solution that is 1.80 M sucrose? The density of solution is 1.08 g/mL.
A
0.0300
B
0.0653
C
0.0699
D
0.9347
E
0.9700
Verified step by step guidance1
Start by understanding the concept of mole fraction, which is the ratio of the number of moles of a component to the total number of moles in the solution.
Calculate the number of moles of sucrose in 1 liter of solution using the molarity. Since the solution is 1.80 M, there are 1.80 moles of sucrose per liter.
Determine the mass of the solution using its density. The density is given as 1.08 g/mL, which is equivalent to 1080 g/L. This is the mass of 1 liter of the solution.
Calculate the mass of sucrose in the solution using its molar mass. Multiply the number of moles of sucrose (1.80 moles) by the molar mass of sucrose (342.3 g/mol) to find the mass of sucrose.
Find the mass of water in the solution by subtracting the mass of sucrose from the total mass of the solution. Then, convert the mass of water to moles using the molar mass of water (18.02 g/mol). Finally, calculate the mole fraction of sucrose by dividing the moles of sucrose by the total moles of sucrose and water.
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