Explanation:
12)
a) Sodium + oxygen = ?
When sodium reacts oxygen its forms sodium oxide as a product.
[tex]4Na(s)+O_2(g)\rightarrow 2Na_2O(s)[/tex]
b) magnesium + fluorine = ?
When magnesium reacts with fluorine its forms magnesium fluoride as a product.
[tex]Mg(s)+F_2(g)\rightarrow MgF_2(s)[/tex]
13)
a) [tex]2HgO(s)\overset{\Delta }\rightarrow 2Hg(l)+O_2(g)[/tex]
Decomposition of mercury(II) oxide on heating gives out mercury and oxygen gas.
b)[tex]2H_2O(l)\overset{Electricity}\rightarrow 2H_2(g)+O_2(g)[/tex]
The electrolytic decomposition of water gives out hydrogen gas amd oxygen gas.
