One mole of any gas always occupies 24 dm3 (=24,000 cm3)
at room temperature and pressure (RTP: 25 degree celcius and 1 atmosphere)
Volume (dm3)= moles of gas x24
Volume (dm3)= (mass of gas/relative atomic mass of gas) x24
Whats the volume of 4.5 moles of chlorine at RTP?
4.5 x 45 dm3= 108 dm3