Basic Units of Measurement and Conversions - Basic Mathematics for Water and Wastewater Operators - page 27

■ Example 2.44
Problem: The label states that the ferric chloride solution has a specific gravity of
1.58. What is the weight of 1 gal of ferric chloride solution?

Solution :

8.34 lb/gal × 1.58 = 13.2 lb/gal

■ Example 2.45
Problem: If we say that the density of gasoline is 43 lb/ft 3 , what is the specific grav-
ity of gasoline?

Solution: The specific gravity of gasoline is the comparison (or ratio) of the density
of gasoline to that of water:

3

Densityofgasoline
Density

43 lb/ft
62.4 lb/ft

Specificgravity = = = 069 .

3

of water

Note: Because the specific gravity of gasoline is less than 1.0 (lower than the spe-
cific gravity of water), it will float in water. If the specific gravity of gasoline were
greater than the specific gravity of water, it would sink.

■ Example 2.46
Problem : The density of SAE 30 motor oil is 56 lb/ft 3 . Find its specific gravity.

Solution:

3

Densityofmotor oil
Densit

56 lb/ft
62.4 lb/ft

Specificgravity = = = 090 .

3

yyofwater

■ Example 2.47
Problem : A liquid chemical has a density of 11.2 lb/gal. What is its specific gravity?

Solution :

Densityofliquidchemical 112 lb/gal

8.34 lb/gal

Specificgravity = = =1.4

Density of water

■ Example 2.48
Problem : The density of chlorine gas (Cl 2 ) is 0.187 lb/ft 3 , and the density of air is
0.075 lb/ft 3 . What is the specific gravity of Cl 2 ?
Solution :

3
3

DensityofCl
Densityofa

0.187 lb/ft
0.075 lb/ft

2

Specificgravity = = = 249 .

ir