A closed, rigid tank contains a two-phase liquid-vapor mixture of Refrigerant-22 initially at −18°C with a quality of 50.9%. Energy transfer by heat into the tank occurs until the refrigerant has become purely a saturated vapor. What is the final temperature, in [°C]? (2°C) What is the net amount of heat per unit mass of refrigerant to/from the tank, in [kJ/kg]? (103 kJ/kg)

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.