the specific gravity of ferric chloride solution

Question

The specific gravity of ferric chloride solution equals 1.3.  How much does one gallon of ferric chloride weigh?

 Solution:  ρ_{ferric chloride} /ρ_water = 1.3      

Conversions:  7.48 gal/ft³ of liquid

8.34 lb/gal of water = 81.12 lb/ft3

ρ_{ferric chloride} = (1.3)(62.4 lb/ft³)

 (81.12 lb/ft³) / (7.48 gal/ft³) = 10.84 lb/gal   OR   (8.34 lb/gal) (1.3)