According to the 1st law of thermodynamics,the sum of the heat gained by a system and the work done on thatsame system is equivalent to what? Is it internal energychange written as: dU = Q - W Is there a better explanation if this is the correctanswer? According to the 1st law of thermodynamics,the sum of the heat gained by a system and the work done on thatsame system is equivalent to what? Is it internal energychange written as: dU = Q - W Is there a better explanation if this is the correctanswer?
Explanation / Answer
Amount of heat given to the system is utilised into twoparts 1. some amount of heat is used to increse the temperature ifthe system i.e., to increse internal K.E of the system( U " ) 2.some energy is used to done a work against attractive forcesi.e., to increase internal potential energy ( U ' ) 3.remaining energy is used to do external work ( W) so, heat given Q = U " + U ' + W = U + W where U = change in internal energy So, change in internal energy U = Q - W