Question

Consider the reaction, C2H4(g) + H2(g) - C2H6(8), where AH = -137 kJ. How many kilojoules are released when 3.5 mol of CH4

Answer 1

Answer: 480 kJ of energy is released when 3.5 mol of $C_2H_4$ reacts.

Explanation:

The balanced chemical reaction is:

$C_2H_4(g)+H_2(g)\rightarrow C_2H_6(g)$  $\Delta H=-137kJ$

Thus it is given that the reaction is exothermic (heat energy is released) as enthalpy change for the reaction is negative.

1 mole of $C_2H_4$ on reacting gives = 137 kJ of energy

Thus 3.5 moles  of $C_2H_4$ on reacting gives = $\frac{137}{1}\times 3.5=480 kJ$ of energy

Thus 480 kJ of energy is released when 3.5 mol of $C_2H_4$ reacts.