The molecular mass of octane is 114.22 g/mol. What is the mass of 22.05 mol of octane?
5.180 g
22.05 g
114.22 g
2,518 g
The correct answer and explanation is:
The correct answer is 2,518 g.
To calculate the mass of 22.05 mol of octane, you can use the formula: Mass=Molar mass×Number of moles\text{Mass} = \text{Molar mass} \times \text{Number of moles}
In this case, the molar mass of octane (C₈H₁₈) is given as 114.22 g/mol, and the number of moles is 22.05 mol. Plugging the values into the formula: Mass=114.22 g/mol×22.05 mol=2,518.4 g\text{Mass} = 114.22 \, \text{g/mol} \times 22.05 \, \text{mol} = 2,518.4 \, \text{g}
Rounding to the appropriate significant figures (since the number of moles is given to three significant figures), the mass of 22.05 mol of octane is approximately 2,518 g.
This calculation uses the concept of molar mass, which tells you how much one mole of a substance weighs. By multiplying the molar mass by the number of moles, you can determine the total mass of a given quantity of a substance. The unit of grams is used because the molar mass is in grams per mole. Therefore, this method ensures that the mass is expressed in grams.
Understanding how to use the molar mass to find the mass of a substance is important in chemistry, especially when working with reactions, stoichiometry, or when preparing chemical solutions.