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 fabrication facility, nitrogen gas is used to purge wafer transport pods. In 1.0 hour1.0\text{ hour}1.0 hour, the facility uses 18 m318\text{ m}^318 m3 of nitrogen gas at a pressure of 140 kPa140\text{ kPa}140 kPa and a temperature of 21∘C21^\circ\text{C}21∘C.
Show that the number of moles nnn of nitrogen used per hour is about 103010301030.
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 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 2.5 kg2.5\text{ kg}2.5 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.