(a)

The
fuel coal is mainly
.
(b)


Oil is a
of many molecules which are compounds of carbon and
and are known as
.
(c)

When fuels burn the carbon and hydrogen atoms combine with the
in air to form
and
vapour.
(d) In a chemical reaction the atoms of the reactants are
to give the
.
(e)

The number of atoms of each
must be the same in the products as in the
.
(f) This is known as the law of
of mass, that is, the mass of reactants
the mass of products.
(g) The properties of the reactants and products are
.
(h)

methane +
==>
+
Per molecule of methane, the reaction illustrated above involves
atom(s) of carbon,
atom(s) of hydrogen,
atom(s) of oxygen and
atoms all together.