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

=? g Air

A:

B:

A: 3.33 mol Air

B: 28.97 g Air

C: 1 mol Air

Mass = 96.47 g

Solution:

Data Given:

M. Mass = 28.97 g. mol⁻¹

Moles = 3.33 mol

Mass = ?

Formula Used:

Moles = Mass : M. Mass

Solving for Mass,

Mass = Moles * M. Mass

Putting values,

Mass = 3.33 mol * 28.97 g. mol⁻¹

Mass = 96.4701 g

Rounding to four significant numbers,

Mass = 96.47 g