Question

50 g of a sample of S on heating gives 7 Litre SO2 at NTP.
Calculate the % amount of S in the sample.
(S = 32, 0 = 16)
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Answer 1

It has given that, 50g of a sample of S on heating gives 7 L SO2 at NTP.

we have to calculate the % amount of S in the sample.

solution : when sulphur burns in the presence of oxygen, S + O2 => SO2

i.e., 32g of sulphur burns and give 22.4 L of SO2 at NTP.

or, 22.4 L of SO2 produces when 32g of sulphur is burnt.

⇒7L of SO2 will produce when 32/22.4 × 7 g of sulphur is burnt.

= 32/22.4 × 7 g = 10 g of sulphur

Therefore mass of sulphur in 50g of a sample is 10g

so, percentage mass of sulphur in the sample = mass of sulphur/mass of the sample × 100

= 10/50 × 100

= 20 %

Therefore 20% amount of S in the sample.