Convert 56.78 grams of Ca (OH) _2 to moles

Answer: 0.77 mole

Explanation:

Atomic mass of Ca = 40g/mol

Atomic mass of O = 16g/mol

Atomic mass of H = 1

Therefore,

1 mole of Ca (OH) _2 contains

40+[16+1]2

= 40+34

=74g/mole

Hence,

1 mole of Ca (OH) _2 = 74g

Let x mole of Ca (OH) _2 = 56. 78

x = 56.78/74

x = 0.77 mole