Question

1) Find number of moles present in 7.4g of Ca(OH)2.
2) Volume occupied by 35.5g of chlorine gas.

Please answer with full explanation.

Answer 1

no of mole = given wt/ molecular wt

= 7.4 g/74 g = 0.1

2) mole = 35.5/71 = 1/2

so, mole = volume/22.4 L
1/2 = volume/22.4 L

volume = 11.2 L

Answer 2

1)
Given mass = 7.4 grams
Molar mass of Ca(OH)₂ = 40 + 2× 16 + 2× 1  = 74 grams

No : of moles = Given mass  ÷ Molar mass  
                      = 7.4 ÷ 74
                      = 0.1 moles

2)
No : of moles = Given volume ÷ Molar Volume

Given mass = 35.5 grams
Molar mass of Chlorine Gas (Cl₂) =  2 × 35.5 = 71 grams

No : of moles = Given mass ÷ Molar mass 
                      = 35.5 ÷ 71
                      = 0.5 moles

Molar Volume is a fixed value = 22.4 Litres

No : of moles = Volume ÷ Molar volume

Volume = No : of moles × Molar volume
             = 0.5 × 22.4
             = 11.2 Litres