A fixed mass of nitrogen changes phase from liquid to gas at a constant temperature.
Explain the change in the total internal energy of the nitrogen.
In a semiconductor manufacturing facility, nitrogen gas is used to create an inert atmosphere. In 1.0 hour1.0\text{ hour}1.0 hour, the facility uses 14 m314\text{ m}^314 m3 of nitrogen gas at a pressure of 125 kPa125\text{ kPa}125 kPa and a temperature of 12∘C12^\circ\text{C}12∘C.
Show that the number of moles nnn of nitrogen used per hour is about 740740740.
Calculate the mass of nitrogen gas used in one hour.
molar mass of nitrogen=0.028 kg mol−1\text{molar mass of nitrogen} = 0.028\text{ kg mol}^{-1}molar mass of nitrogen=0.028 kg mol−1
The volume of nitrogen being used cannot be changed.
State how the rate of mass of nitrogen used can be reduced.
The nitrogen at the facility is stored as a liquid. The liquid expands at constant temperature to form gas in a short section of pipe.
When the surrounding air temperature is 0∘C0^\circ\text{C}0∘C, a thick layer of ice forms on the outside of the pipe from water vapour in the air. In 1.0 hour1.0\text{ hour}1.0 hour, the mass of ice formed is 1.6 kg1.6\text{ kg}1.6 kg at a temperature of 0∘C0^\circ\text{C}0∘C.
Use this data and your answer to (b)(ii) to estimate the specific latent heat of vaporisation LLL of nitrogen.