Question

determine the heat evolution inside a horizontal tube heated at the bottom at a temperature of 40 degree celsius, diameter of the tube is negligible and tube length is 1m, v =1cm/sec

Answer 1

Heat evolution is the measure of enthalpy $(\triangle h)$

$(\triangle h) =u+PV$ , but u, the internal energy is zero

$(\triangle h) =Pv$

$\frac{P}{T}=k \implies P=kT, if \space k=1, P=T=40+273=313K$

$(\triangle h) =313 \times \frac{1cm}{sec} \times\frac{1m}{100cm} \times 1kg=3.13 kg/ms$

$(\triangle h)=31.3 J$