Toluene, C6H5CH3, is a liquid similar to benzene, C6H6. It is the starting material for other substances, including trinitrotoluene (TNT). Find the molality of toluene in a solution that contains 26.2 g of toluene and 132 g of benzene.
To find the molality of toluene in the solution, we need to first determine the number of moles of toluene and the mass of the solvent (benzene).
1. Calculate the number of moles of toluene:
The molar mass of toluene (C6H5CH3) is:
(6 * atomic mass of carbon) + (5 * atomic mass of hydrogen) + (1 * atomic mass of methyl group)
= 6(12.01 g/mol) + 5(1.01 g/mol) + 1(15.03 g/mol) = 92.14 g/mol
Now, we can calculate the number of moles of toluene:
Moles of toluene = Mass of toluene / Molar mass of toluene
= 26.2 g / 92.14 g/mol
2. Calculate the mass of benzene:
Mass of benzene = 132 g
3. Calculate the molality of toluene in the solution:
Molality (m) = Moles of solute / Mass of solvent (in kilograms)
= Moles of toluene / (Mass of benzene / 1000 g/kg)
Now, let's plug in the values and calculate the molality:
Moles of toluene = 26.2 g / 92.14 g/mol
≈ 0.284 mol
Mass of benzene = 132 g
Molality (m) = 0.284 mol / (132 g / 1000 g/kg)
= 0.284 mol / 0.132 kg
≈ 2.152 mol/kg
Therefore, the molality of toluene in the solution is approximately 2.152 mol/kg.