Sample interview questions: How do you calculate the critical point of a substance?
Sample answer:
The critical point of a substance represents the temperature and pressure conditions at which the liquid and gaseous phases become indistinguishable. To calculate the critical point, follow these steps:
1. Determine the Critical Temperature (Tc):
- Use experimental data or thermodynamic equations of state to determine the boiling point of the liquid at various pressures.
- Plot the data as a graph of pressure versus temperature.
- Extrapolate the data to the temperature where the vapor pressure curve and the liquid-vapor equilibrium curve meet. This point represents the critical temperature (Tc).
2. Determine the Critical Pressure (Pc):
- At the critical temperature (Tc), the vapor pressure curve and liquid-vapor equilibrium curve merge.
- Th… Read full answer