to find:
the amount of energy absorbed when 240 dm3 of hydrogen, measured at room temperature and pressure, is formed.
solution:
According to Avogadro's law 1 mole of any gas occupies 22.4 L (dm3) at room temperature and pressure.
So the amount of energy absorbed:
(kJ)E=131∗240/22.4
=1403.6(kJ)
1403.6 kJ is absorbed when 240 dm3 of hydrogen, measured at room temperature and pressure is formed.