A sealed glass bulb of fixed volume is used as a gas thermometer
PHYSICS · Multi-part · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics
Problem
A sealed glass bulb of fixed volume is used as a gas thermometer. The bulb is filled with nitrogen gas. When the bulb is immersed in an ice–water mixture at 0.00 °C, the pressure inside is measured to be 1.013×105Pa. The bulb is then warmed in successive water baths, and the following data are collected.
Temperature (°C): 20 40 60 80
Corresponding pressure (Pa): 1.09×1051.16×1051.23×1051.31×105
Assume the quantity of gas in the bulb remains constant and the volume of the bulb does not change. Atmospheric pressure is 1.013×105Pa. The universal gas constant is 8.31J mol−1K−1.
(a) Use the trend in the data to predict the pressure inside the bulb when its temperature is raised to 100∘C. Show your reasoning.
(b) On graph paper, sketch a plot of pressure versus absolute temperature based on the data provided. Explain how the shape and intercept of this graph can be used to estimate the temperature at which the pressure of the gas would become zero.
(c) Extrapolate your sketch quantitatively (showing numerical work) to estimate that temperature. Express your answer in degrees Celsius.
(d) Explain, in terms of the microscopic behavior of the gas particles, why the pressure approaches zero at the temperature you found in part (c).