This equation shows how the volume of gas in dm3 at rtp is related to the number of moles:
Calculate the volume of 0.5 mol of carbon dioxide at rtp.
volume = 0.5 × 24 = 12 dm3
Remember that 1 dm3 = 1 000 cm3 so the volume is also 12 000 cm3
The equation can be rearranged to find the number of moles, if the volume of gas at rtp is known:
number of moles = volume of gas at rtp ÷ 24
Calculate the number of moles of hydrogen that occupy 6 dm3 at rtp.
number of moles = 6 ÷ 24 = 0.25 mol