Question

A cylinder contains 68 g of ammonia gas at STP.

1) What is the volume occupied by this gas?

2) How many moles of ammonia are present in the cylinder?

3) How many molecules of ammonia are present in the cylinder?

[N = 14, H = 1]

Answer 1

A cylinder contains 68 g of ammonia gas at STP.

1) Molecular weight of ammonia = 17 g/mole

68 g of ammonia gas at STP = ?

1 mole = 22.4 dm³

∴ 4 mole = 22.4 × 4 = 89.6 dm³

2) 4 moles of ammonia gas is present in the cylinder

3) 1 mole = 6.023 × 10²³ molecules

4 moles = 24.092 × 10²³ molecules