Question

The mass of a litre of dry air at N.T.P is 1.293
g. Find the mass of 3 litres of air at 117°C and
a pressure of 4 atmospheres ?
1) 10.86 g
2) 5.6 g
3) 6.4 g
4) 7.2 g

Answer 1

The mass of a litre of dry air at N.T.P is 1.293g. Find the mass of 3 litres of air at 117°C and a pressure of 4 atmospheres ?

answer : option (1) 10.86g

explanation : The mass of one litre of dry air at NTP , m = 1.293g

at NTP, temperature, T1 = 273K , pressure , P1 = 1atm and given, volume of dry air , V = 1L

we have to find mass of air

when pressure of air , P2 = 4atm

volume of air, V2 = 3Litre

and temperature , T = 117°C = 390K

using formula, P1V1/m1T1 = P2V2/m2T2

or, (1atm × 1L)/(1.293g × 273K) = (4atm × 3L)/(m2 × 390K)

or, 1/(1.293 × 273) = 12/(390m2)

or, m2 = (1.293 × 273 × 12)/390

= 10.86 g

hence mass of air is 10.86g

Answer 2

Answer:

10.86

Explanation:

1.293×273×12/390

10.86