A solution is made by mixing 35.0 mL of toluene C6H5CH3d=0867gmL with 125.0 mL of benzene C6H6d=0874gmL. Assuming that the volumes add upon mixing, the molarity (M) and molality (m) of the toluene are
Molarity=molestoluene/volumesolutioninliters
molality= molestoulene/(kg benezene)
Do you have any questions on how to do these?
how do you get the volume of the solution
and how do you get moles of toluene? please
To find the molarity (M) and molality (m) of the toluene solution, we first need to calculate the number of moles of toluene (C6H5CH3) in the solution.
Step 1: Calculate the mass of toluene in grams.
The density of toluene is given as 0.867 g/mL. So, the mass of 35.0 mL of toluene can be calculated as:
Mass of toluene = volume × density = 35.0 mL × 0.867 g/mL = 30.345 g
Step 2: Convert the mass of toluene to moles.
To find the moles of toluene, we need to know its molar mass. The molar mass of toluene (C6H5CH3) can be calculated by adding up the atomic masses of all its atoms:
Molar mass of toluene = (6 × atomic mass of carbon) + (5 × atomic mass of hydrogen)
The atomic mass of carbon (C) is 12.01 g/mol, and the atomic mass of hydrogen (H) is 1.01 g/mol.
Molar mass of toluene = (6 × 12.01 g/mol) + (5 × 1.01 g/mol) = 92.15 g/mol
Now, we can find the number of moles of toluene by dividing the mass by the molar mass:
Moles of toluene = mass / molar mass = 30.345 g / 92.15 g/mol = 0.3298 mol
Step 3: Calculate the molarity (M) of the toluene solution.
Molarity is defined as the number of moles of solute (toluene) per liter of solution.
To find the molarity, we need to know the total volume of the solution. The total volume is the sum of the volumes of toluene and benzene, which is 35.0 mL + 125.0 mL = 160.0 mL = 0.160 L (since 1 L = 1000 mL).
Molarity (M) = Moles of toluene / Total volume of solution
M = 0.3298 mol / 0.160 L = 2.06 M (rounded to two decimal places)
Step 4: Calculate the molality (m) of the toluene solution.
Molality is defined as the number of moles of solute (toluene) per kilogram of solvent (benzene).
To find the molality, we need to convert the mass of benzene to kilograms.
Mass of benzene = volume × density = 125.0 mL × 0.874 g/mL = 109.25 g
Mass of benzene in kg = 109.25 g / 1000 = 0.10925 kg
Molality (m) = Moles of toluene / Mass of benzene in kilograms
m = 0.3298 mol / 0.10925 kg = 3.02 m (rounded to two decimal places)
Therefore, the molarity (M) of the toluene solution is 2.06 M and the molality (m) is 3.02 m.