Calculate gas density using the ideal gas law and molecular weight
d = PM/RT
d = density, P = pressure, M = molar mass, R = gas constant, T = temperature
1 atm = 101,325 Pa
1 atm = 760 mmHg
1 atm = 14.7 psi
K = °C + 273.15
K = (°F + 459.67) × 5/9