Answer:
To calculate the mole fraction of benzene in a solution containing 30% by mass benzene, you will need to know the molar mass of benzene and the mass of the solution.
First, calculate the mass of the benzene in the solution. If the solution is 30% by mass benzene, then the mass of the benzene is 30% of the total mass of the solution. Let's say the mass of the solution is 100 grams. The mass of the benzene in the solution would be 100 g * 30% = 30 g.
Next, calculate the moles of benzene in the solution. You can use the following formula to do this:
Moles = Mass / Molar mass
The molar mass of benzene is 78.11 g/mol, so the number of moles of benzene in the solution is:
Moles = 30 g / 78.11 g/mol = 0.385 moles
To calculate the mole fraction of benzene, you will need to divide the number of moles of benzene by the total number of moles in the solution. To find the total number of moles, you will need to convert the mass of the carbon tetrachloride to moles using the molar mass of carbon tetrachloride. Let's say the mass of the carbon tetrachloride is 70 g. The number of moles of carbon tetrachloride in the solution is:
Moles = 70 g / 153.82 g/mol = 0.455 moles
The total number of moles in the solution is the sum of the moles of benzene and the moles of carbon tetrachloride:
Total moles = 0.385 moles + 0.455 moles = 0.840 moles
To find the mole fraction of benzene, divide the number of moles of benzene by the total number of moles:
Mole fraction of benzene = 0.385 moles / 0.840 moles = 0.457
This means that the mole fraction of benzene in the solution is approximately 45.7%.
Step-by-step explanation: