Question

If 0.15 moles of water react, how many grams of calcium hydroxide are formed? (5.6)

Answer 1

Ca(s) + 2H2O(l) --->Ca(OH)2(aq) + H2(g)

1 : 2 1 : 1

n H2O = 0.15 moles

for every 2mole ratio of H2O = 0.15 moles

relate to the mole ratio of calcium hydroxide.

2 mole ratio = 0.15moles

1 mole ratio = ?

= 0.075 moles.

from,

n = mass/molar mass

Molar mass of Ca(OH)2 = 74g/mol

n Ca(OH)2 = 0.075moles

m Ca(OH)2 = 74*0.075

m Ca(OH)2 = 5.55grams.

The grams of calcium hydroxide formed are 5.55g.