1 g of water at atmospheric pressure has volume of 1 cc and when boiled it becomes 1681 cc of steam. The heat of vaporisation of water is 540 cal / g . Then the change in its internal energy in this process is

Step-by-step solution

( aligned & Initial volume of water =V₁=1 ~cm ^3 & Volume of steam =V₂=1681 ~cm ^3 & Change in volume dV = V ₂- V ₁=1681 & =168 ocm ^3 & =168 o 10⁻⁶ ~m ^3 & Pressure p=10^5 ~N / m ^2 & dQ = mL =1 540 4.2 & =22.68 ~J & dW = pdV & =10^5 168 o 10⁻⁶=168 & Internal energy dU =2268-168=2100 ~J & =500 cal aligned )