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
