How Does Compressibility Chart Predict Final Pressure in a Heated Rigid Vessel?

[MEAHH]

Thermo Help! Compressbility

Homework Statement

Ethane in a rigid vessel is to be heated from 50 psia and 100 F until its temperature is 600 F. What is the final pressure of the ethane as predicted by the compressibility chart?

Homework Equations

Pr=P/Pcr
Tr=T/Tcr
Pv=zRT

The Attempt at a Solution

this is a constant volume process.
I found the z for the first state to be 0.95
I don't understant hoe to find the final pressure, i tried to solve 2 Pv=RT equations to get

z1T1/P1=z2T2/P2 but i am unable to find the second z factor so i am unable to solve for p2 and i going about this right

 

[Nate810]

? No, you should not be solving this using the ideal gas law. Instead, you should look up the compressibility factor of ethane on a compressibility chart and use it to find the final pressure. The compressibility factor is determined by the temperature and pressure of the gas, so you will need to look up the compressibility factor for the final state of 600 F and 50 psia. The final pressure can then be determined using the equation P = ZPcr, where Pcr is the critical pressure of ethane (47.7 psi).

 

[nlightner]

?I would respond by saying that the compressibility chart is a useful tool in predicting the final pressure of a gas undergoing a temperature change in a rigid vessel. However, in this specific scenario, there are some missing variables that would be needed to accurately calculate the final pressure. For example, the specific gas constant for ethane would be needed to solve the second Pv=RT equation. Additionally, the compressibility chart may not be accurate for extreme temperature changes, as it is typically based on experimental data at standard conditions. Therefore, it would be best to consult other sources or perform further calculations to accurately determine the final pressure of the ethane in this scenario.