5g of a gas is contained in a rigid container and is heated from 15°C to 25°C. Specific heat capacity of the gas at constant volume is 0.172 cal g–1°C–1 and the mechanical equivalent of heat is 4.2 J cal–1. Calculate the change in the internal energy of the gas.
Given:
Mass of the gas(m) = 5g
Change in temperature(dT) = 10°C
Specific heat at constant volume(Cv) = = 0.172 cal g–1°C–1
Mechanical equivalent of heat = 4.2 J cal–1
Formula used:
Change in internal energy = mCvdT
Where,
m = Mass of the gas
Cv = Specific heat at constant volume
dT = Change in temperature
Also, we know,
Heat(Joule)= Mechanical equivalent of heat× Heat(cal)
Putting the values in the above formula, we get
= (5x10x0.172) cal
= 8.6 cal = (8.6x4.2)J
= 36.12 J (Answer)