Thermodynamic help! - Steam tables?
For a certain experiment, R-410a vapor is contained in a sealed glass tube at 20°C. It is
desired to know the pressure at this condition, but there is no means of measuring it, since
the tube is sealed. However, if the tube is cooled to −20°C small droplets of liquid are
observed on the glass walls. What is the initial pressure?
- Lee Wang TuiLv 79 years agoFavorite Answer
Pi = ?
Ti = 20°C
Tf = - 20°C = T sat(saturated condition)
Cooling process is a process of decreasing temperature with constant pressure. So, initial pressure and final pressure will be the same.
Tf and Pf are dependent, you can look saturated pressure for saturated condition.
T sat = -20°C, then P sat = 3.99551185 bar, so Pi = 3.9955 bar