A constant volume gas theremometer using helium, records a pressure of `20.0 kPa` at the triple point of water and pressure of `14.3 kPa` at the temperature of dry ice. What is the temperature of dry ice.?

Explanation

Given `V_(1)=V_(2),P_(1)=20kpa,T_(1)=273.15K`
`P_(2)=14.3kpa,T_(2)=?`
Using Gay Lussac Law,
`(P_(1))/(P_(2))=(P_(2))/(T_(2))` at constant volume we get
`(20xx10^(3))/(273.15)=(14.3xx10^(3))/(T_(2))" "ie.T_(2)=(14.3xx273.15)/(20)`
`T_(2)=195.3K`
Temperature of dry ice is 195.3K `(=-77.7^(@)C)`.