2018 - JAMB Chemistry Past Questions and Answers - page 2

N\(_{2(g)}\) + 3H\(_{2(g)}\) ⇔ 2NH\(_{3(g)}\) In the Haber process, the forward reaction is exothermic and the backward reaction is endothermic. If the temperature is decreased, the yield from the exothermic direction is increased i.e. the forward reaction is increased.

Formula for enthalpy change: ΔH = ΔU + Pex(ΔV)

  The enthalpy change is zero because both terms on the right are zero in free expansion of an ideal gas.

  There is no external pressure in a free expansion, so P (ex) = 0. And the internal energy change, ΔU of free expansion in a closed system is zero since no inter molecular forces have to be overcome. The temperature remains constant and no heat is absorbed or released.

Alkanones (also known as ketones) have the general formula R\(_2\)CO

Clay minerals are hydrous aluminium phyllosilicates, sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces.