Question

The molecular mass of air, at standard pressure and temperature, is approximately 28.97 g/mol.

Calculate the mass of 3.33 moles of air.
First, complete the unit conversion using dimensional analysis:
A • B/C
A: answer: 3.33 mil air
B: answer: 28.87 g air
C: answer: 1 mol air

Answer 1

We are given:

Molar mass of air = 28.97 grams/mole

Amount of Air in question = 3.33 moles

Mass of 3.33 moles:

We know that:

mass = molar mass * number of moles

replacing the variables

mass = 28.97
`(grams)/(mol)` * 3.33 moles

[the 'mole' in the numerator and the denominator will cancel out]

mass = 28.97 * 33.3 grams

mass = 96.47 grams