Question

air expands from 5 litres to 10 litres at 2 atm pressure. external work done is

Answer 1

Work done = PdV = P(V2-V1)
1atm=10^5 pascals(approx)
2atm=2x10^5 Pa
workdone=(2x10^5)(10-5)=10x10^5= 10^6joules...
value of atm into pascals is approximate value

hope this helps:)

Answer 2

W=PhD
P=1atm=1×10^5pa
2atm =20×10^5pa
W=P (v2-v1)
W=20×10^5×(10-5)
W=100×10^5
W=10^7J