Question

Gaseous hydrogen enters a constant-area pipe with a temperature of 300 K, and exits with a temperature of 650 K with no mass accumulation in the pipe. Assuming the hydrogen is an ideal gas and that it has a constant specific heat, how much heat is transferred per unit mass to the hydrogen as it passes through the pipe

Answer 1

Answer:

ΔQ = 5054 KJ/kg.K

Explanation:

First of all, we will find the value of the specific heat of hydrogen. Since it is mentioned that the value of specific heat is constant between 300 K and 650 K. Therefore, we can take it to be the average of values at these two temperatures.

$Constant\ Specific\ Heat\ of\ Hydrogen = C = \frac{Specific\ Heat\ at\ 300\ K + Specific\ Heat\ at\ 650\ K}{2} \\C = \frac{(14.31 + 14.57)KJ/ kg.K}{2}$C = 14.44 KJ/ kg.K

Now, the heat absorbed is given by the following formula:

$\Delta Q = C(T_{f} - T{i})$

where,

T_f = Final Temperature = 650 K

T_i = Initial Temperature = 300 K

$\Delta Q = (14.44\ KJ/kg.K)(650\ K - 300\ K)$

ΔQ = 5054 KJ/ kg.K