Question

A cylindrical air tank has dimensions diameter = 0.2m and height 0.8m. an attached pressure gage reads 200 kPa and the temperature is 27 celcius. an electrical heater is energized inside and it raises the temperature to 147 celius in 2 minutes. Calculate the mass of air in the tank (kg) (have to use ideal gas law, molecular weight of air)

Answer 1

V = 3.1416*(0.1*0.1)*0.8 = 0.025133 m3 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- P V = n R T ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ==> n = P V/(R T) = 200e3*0.025133/(8.314*(27+273)) = 2.0153 moles ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- molar mass of dry air is 0.02897 Kg/mol ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ==> mass = m = 2.0153 * 0.02897 = 0.0584 Kg