download the exercise with solution: ideal gas law
A bottle with volume 3 m3 is filled with oxygen gas. Its temperature is 20°C and pressure equals 1.45 bar. The molar mass of oxygen is M=32 g/mol. Oxygen gas here is assumed to be ideal gas. Please determine:
1) the mass of gas in bottle;
2) the number of oxygen gas molecules.
1) We first determine the specific gas constant for oxygen gas:
where R=8.314 J/mol∙K is the universal gas constant.
Then we calculate the gas mass through the ideal gas law:
2) We should first calculate the mole of gas in bottle: n=m/M Here NA is Avogadro constant and equals 6.022∙1023mol-1