Chemical and Nuclear Reactions - Chemistry - page 174

Examples of Single Replacement Reactions
K (s) + NaCl (aq) KCl + Na (s)

Cl 2(g) + 2LiBr (aq) 2LiCl (aq) + Br 2(l)

potassium replaces sodium chlorine replaces bromine

F 2(g) + 2NaI (aq) 2NaF (aq) + I 2(s) Zn (s) + 2HCl (aq) ZnCl 2(aq) + H 2(g)

fluorine replaces iodine zinc replaces hydrogen

A double replacement reaction occurs when two ionic compounds react
in an aqueous solution, and an ion from one compound replaces the similar
ion from the other compound. The general format for a double reaction is:
AB + CD CB + AD

compound + compound compound + compound

Double replacement reactions can be misleading, as they are written,
because the compounds that are written as “products” do not always form.
You should pay attention to subscripts to see the form of the products. If
the phase is solid, liquid, or gas, then the product will actually form, at least
to some extent. If the subscript is “aq” (for “aqueous”), it means that the
ions are dissociated in water. Double replacement reactions are also called
double displacement reactions.

Examples of Double Replacement Reactions
Ba(OH) 2(aq) + H 2 SO 4(aq) BaSO 4(s) + 2H 2 O (l)

Ca(OH) 2(aq) + Na 2 CO 3(aq) 2NaOH (aq) + CaCO 3(s)

3CaCl 2(aq) + Al 2 (SO 4 ) 3(aq) 3CaSO 4(aq) + 2AlCl 3 (aq)

AgNO 3(aq) + NaCl (aq) AgCl (aq) + NaNO 3(aq)

A combustion reaction occurs when a hydrocarbon, which is an organic
compound that contains only hydrogen and carbon, reacts with oxygen to
produce water and carbon dioxide. In some ways, combustion reactions
are the easiest of the types of chemical reactions to identify, because oxy-
gen is always a reactant and the products are always carbon dioxide and
water. The general form for a combustion reaction is shown here:
hydrocarbon + oxygen carbon dioxide + water