Question

3.49g of ammonia at stp occupies volume of 4.48 dm3 calculate the molar mass of ammonia

Answer 1

volume = 4.48 dm3 = 4.48 L

gram molecular mass = 22.4 L at STP

so, 4.48 L of ammonia gas weighs= 3.49 g

22.4 L of ammonia weighs = 22.4 x 3.49 /4.48

= 17.45 g

Answer 2

Relative molar mass of ammonia is to be calculated instead of molar mass.

4.48 dm³ = 4.48 L

As we know,

Gram molecular mass = 22.4 L at STP

Thus we can say that,

4.48 L of ammonia gas weighs 3.49 g

22.4 mL of gas will weigh = 22.4 × 3.49 ÷ 4.48

= 17.45 g

Hence relative molar mass of gas Ammonia is 17.45 g