The pressure of a gas at the triple point of water is 1.50 atm, which means it is at the temperature and pressure where water can exist as a solid, liquid, and gas simultaneously.
To find the pressure of the gas at the temperature at which CO2 solidifies, we need to know the triple point of CO2. The triple point of CO2 is -56.6°C and 5.1 atm.
If the volume of the gas remains unchanged, then its pressure will change with a change in temperature. Using the ideal gas law, PV = nRT, we can find the new pressure of the gas:
P1V1 = P2V2
At the triple point of water:
P1 = 1.50 atm
V1 = V (unchanged)
T1 = 0.01°C (triple point of water)
At the triple point of CO2:
P2 = 5.1 atm
V2 = V1 (unchanged)
T2 = -56.6°C
Using the ideal gas law and solving for P2:
P2 = P1(T2/T1)
P2 = 1.5 x (-56.6+273.15) / (0.01+273.15)
P2 = 0.818 atm
Therefore, the pressure of the gas at the temperature at which CO2 solidifies is 0.818 atm.