I need help solving this

Question

Air weighs about 8.0 lb per 100. Cubic feet.What is the density of air in

a) gram per cubic feet

b) gram per cubic liter

Answer 1

This is a problem of conversions and probably should use dimensional analysis.

Conversion factors needed are:

lbs to grams (454 g = 1 lb)

cubic feet to liters (I'm assuming you meant liters because we really don't have such units as cubic liters): 1 ft3 = 28.3 L

(a) 8.0 lb/ft³ x 454 g/lb = 3632 g/ft³ = 3600 g/ft³ (to 2 sig. figs.)

(b) 3600 g/ft3 x 1 ft3/28.32 L = 127 g/L = 130 g/L (to 2 sig. figs.)