An open flask sitting in a lab fridge looks empty, but we know that actually it is filled with a mixture of gases called air. if the flask volume is 1.50 l, and the air is at standard temperature and pressure, how many gaseous molecules does the flask contain?
use ideal gas law PV=nRT at STP, pressure is 1atm and temperature is 273K (0 Celsius) 1×1.5L=n × 0.0821 × 273 n is moles and R is ideal gas law constant, always 0.0821 moles= 14.9422(6.02×10^23 molecules)=9.0×10^24 molecules
