Question

Six kilograms of nitrogen at 30 °C are cooled so that the internal energy decreases by 60 kJ. Find the final temperature of the gas. Assume that the specific heat of nitrogen is 0.745 kJ / kg °C.

Answer 1

Final temperature will be 16.57°C

Step-by-step explanation:

We have given mass of nitrogen m = 6 kg

Initial temperature
`T_1=30^(\circ)`

Decrease in internal energy
`\Delta U=-60KJ`

Specific heat of nitrogen
`c_v`= 0.745 KJ/kg

Let final temperature is
`T_2`

Change in internal energy is given by
`\Delta U=mc_v\Delta T=mc_v(T_2-T_1)`

`-60=6* 0.745(T_2-30)`

`T_2=16.57^(\circ)C`

So final temperature will be 16.57°C