Question

Calculate the volume of Oxygen gas at 17°C and 800 torr that may be obtained by complete decomposition of 50.5 g of KNO3. (Atomic mass; K = 39, N =14, O = 16) (8) 2KNO3 = 2KNO2 + O2

Answer 1

Answer:

Answer

Correct option is

B

101 g

S+O

2

⟶SO

2

Moles of S =

32g/mol

16g

=0.5 mol

0.5 mol of S requires 0.5 mol of oxygen.

So, we know that sulphur burns in 0.5 mol oxygen.

The thermal decomposition of Pottasium nitrate:

2KNO

3

⟶2KNO

2

+O

2

1 mol of O

2

is produced by 2 mol of KNO

3

0.5mol of O

2

will be produced by 1 mol of KNO

3

Thus, 1 mole of KNO

3

is required to produce the given amount of oxygen.

1 mol of KNO

3

= molar mass of KNO

3

=101 g

Hence, option B is correct