How many grams of calcium hydroxide Ca (OH) 2 are needed to make 532.0 mL of a 1.90M solution?

Answer: m = 74.7 g Ca (OH) 2

Explanation: To solve this problem we will use the formula for Molarity which is M = n / L, where n is the number of moles and L represents volume in liters. Derive for n to find moles then convert it to mass using the molar mass of the compound.

First convert mL to L

532.0 mL (1 L / 1000 mL) = 0.532 L

n = M L

= 1.90 M (0.532 L)

= 1.01 moles Ca (OH) 2

Convert moles to mass:

= 1.01 moles Ca (OH) 2 x 74 g Ca (OH) 2 / 1 mole Ca (OH) 2

= 74.7 g Ca (OH) 2