An airplane is flying at an altitude at which its temperature and pressure are 255 k and 4.72x10^4 pa. calculate the following altitudes to the nearest 100 m. a) pressure altitude b) temperature altitude c) density altitude

Ahe-xe mixture containing a 0.75 mole fraction of helium is used for cooling electronics in an avionics application. at a temperature of 300 k and atmospheric pressure, calculate the mass fraction of helium and the mass density, molar concentration and molecular weight of the mixture. if the cooling capacity is 10 l, what is the mass of the coolant?