Question

A volume of 1.50 L of argon gas is confined in a cylinder with a movable piston under a constant pressure of 1.22 x 10^5 Pa. when 1.25 kJ of energy in the form of heat is transferred from the surrounding to the gas, the internal energy of the gas increases by 1.11 kJ. What is the final volume of Argon gas in the cylinder?

Answer 1

From first law of thermodynamcis

delU =Q+W

where del U= Change in internal energy . =1.11Kj

heat is transferred from surroudings to system and hence positive, Q= 1.25 Kj

1.11 =1.25 + W

W= -0.14 Kj

but W= -P dV = -P* (V2-V!1) where P is pressure and dV is change in volume=V2-V1

P =1.22X10⁵ Pa= 1.22*10⁵/1000 Kpa=122 KPa

Initial volume,V1= 1.5 liters =1.5/1000 =0.0015m³

122*(V2-0.0015)=-0.14

V2-0.0015 =-0.14/122=-.00115

V2= 0.0015-0.00115=0.000352 m3 =0.000352*1000=0.35 liters