Final answer:
The mole fraction of I2 in a solution made by dissolving 139 g of I2 in 245 g of hexane is calculated by finding the number of moles of each substance and dividing the moles of I2 by the total moles. It results in a mole fraction of 0.161.
Step-by-step explanation:
To determine the mole fraction of I2 in a solution, you first need to calculate the moles of I2 and the moles of hexane, C6H14. The molar mass of I2 is roughly 253.8 g/mol (126.9 g/mol per iodine atom).
The moles of I2 are calculated as follows:
Moles of I2 = 139 g / 253.8 g/mol = 0.547 moles.
The molar mass of hexane (C6H14) is calculated by adding the molar masses of its individual atoms: 6 carbon atoms (6 x 12.01 g/mol) + 14 hydrogen atoms (14 x 1.008 g/mol) which equals approximately 86.18 g/mol.
Moles of hexane = 245 g / 86.18 g/mol = 2.842 moles.
The mole fraction of I2, XI2, is the moles of I2 divided by the total moles of both substances:
XI2 = 0.547 moles of I2 / (0.547 + 2.842) moles of total substance = 0.547 / 3.389 = 0.161.
Therefore, the mole fraction of I2 in the solution is 0.161.