Question

How many moles of sebacoyl chloride do you have if you measure out 5 mL of a 9% volume/volume solution in cyclohexane?

Density: Cyclohexane 0.7781 g/mL. Sebacoyl chloride 1.121 g/mL

Molar mass: Cyclohexane 84.16 g/mol. Sebacoyl chloride 239.14 g/mol

Answer 1

Concentration sebacoyl chloride = 9% (v/v) = 9 mL sebacoyl chloride / 100 mL solution

Volume of solution measured = 5 mL

volume of sebacoyl chloride = (Volume of solution measured) * (Concentration sebacoyl chloride)

volume of sebacoyl chloride = (5 mL) * (9 mL sebacoyl chloride / 100 mL solution)

volume of sebacoyl chloride = (5 * 9) / 100 mL

volume of sebacoyl chloride = 0.45 mL

mass sebacoyl chloride = (volume of sebacoyl chloride) * (density of sebacoyl chloride)

mass sebacoyl chloride = (0.45 mL) * (1.121 g/mL)

mass sebacoyl chloride = 0.50445 g

moles sebacoyl chloride = (mass sebacoyl chloride) / (molar mass sebacoyl chloride)

moles sebacoyl chloride = (0.50445 g) / (239.14 g/mol)

moles sebacoyl chloride = 2.1 x 10^-3 mol