, where b≠0 and d≠ 0.
Chem 101 with Math Reactivation
In chemistry, setting up equations as proportions is a quick and efficient way to solve many different problems.
Proportions
A proportion is two equal ratios, that is
, where b≠0 and d≠ 0.
For example, 
.
Proportion Property
In any proportion if
, then ad = bc.
Proof: Multiply both sides of the proportion by its common denominator
ad = bc
1. Solve:
a)
b)
3∙8 = 5x 7∙2 = 20x
x = 4.8 0.7 = x
2. If 100 grams of ice cream contains 13 grams of fat, how much fat is in 350 grams of ice cream?
or 
3. A 60 mL aqueous (in water) solution contains 25 mL of alcohol. If 1.0L of alcohol in water solution is to have the same concentration of alcohol, how much alcohol must it contain?
4. The density of titanium is 4.54 g/cm3. What is the volume of 77.2 g of titanium?
