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)


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