2017 - JAMB Chemistry Past Questions and Answers - page 1

Alkanones also known as ketones have the general formula R₂CO

Constituents of duralumin are: Al, Cu, Mg, Mn.

Constituents of Alnico are: Al, Ni and Co

In 1909, the alloy of duralumin was discovered by Alfred Wilon consisting of 94% Al, 4% Cu, 1% Mg and 1% Mn(Manganese)

Alnico is an acronym referring to a family of iron alloys which in addition to iron are composed primarily of Al, Ni and Co.

The shape of the S-orbital is spherical.

Aluminium hydroxide is used in the dyeing industry as a mordant. It combines with a dye and thereby fixes it in a material.

It is also called weak iodine solution. Tincture solutions are characterized by the presence of alcohol.

Permanent hardness in water= Mg & Ca Sulphate.

Temporary hardness in water= Mg & Ca Carbonate.

Temporary hardness of water is caused by Magnesium and calcium hydrogencarbonate. It is formed when rainwater containing dissolved CO₂ flows over deposit of CaCO₃

i.e CaCO₃ + CO₂ + H₂O → Ca(HCO₃)₂

H₂CO₃ is an example of a weak acid while H₂SO₄ and HNO₃ are examples of a strong acid.

CO₂ combines with water to give a weak trioxocarbonate (IV) acid.

CO₂ + H₂O → H₂CO₃

Resonance involves two forms of a compound.

Isomerism involves two or more forms of an element.

Reforming involves the rearrangement of molecule.

This deals with a two forms of a molecule where the chemical connectivity is the same but the electrons are distributed differently around the structure.

This is used in the preparation of ethyl ethanoate to remove the water present since it serves as a dehydrated agent.

The constituent of air includes O₂, CO₂, N₂ and Noble gases. While for a rusting process to take place, the presence of O₂, H₂O and CO₂ is important.

The constituent of air includes O₂, CO₂, N₂ and Noble gases and for rusting process to take place.

The presence of O₂ and CO₂ as a constituent of air is indispensable