Answer to Question #204295 in Molecular Physics | Thermodynamics for abdul rahman

Question

A combustion engine is to be used for gas compressor in the cylinder. Initial expansion,internal energy is 1000kJ/kg. At the end of the process, the internal energy has been decreased by 700kJ/kg. Calculate the heat transfer if the work done to the system is

0.2MJ/kg and state either the heat is rejected or transferred to the system.

Answer 1

Gives

$U_i=1000kJ/kg$

$U_f=700kJ/kg$

W=0.2MJ/kg =200kJ/kg

We know that

$∆Q=∆U+∆W$

$∆Q=(U_f-U_i)+∆W$

$∆Q$ =(700-1000)+200 kJ/kg

$∆W=$ -300+200=-100 kJ/kg

$∆Q=-100KJ/kg$

Heat is rejected for the system