Two sealed flasks with the same volume are left side by side. Flask A contains 4.0 × 10−3 mol of methane.
Flask B contains 340 mg of a different gas.
Both gases are at the same temperature and pressure. Which gas could be in Flask B?
M2 = m2/n2 = 0,34/0,004 = 85 g/mol
If the temperature is higher then 40°C, gas in 2-th flask is a CH2Cl2.