1. Ionic equations
A chemical equation shows the number of atoms and molecules of the reactants and products.
Also shows physical state of reactants and products.
However, does not show clearly the reactions of ionic compounds.

2. Ionic equations
An ionic equation shows only the ions taking part in the reaction and leaves out the ions that do not react.

3. Writing ionic equations
Procedure is similar as writing chemical equations.
A) Ionic compounds when dissolved in water dissociate completely into ions.
B) Spectator ions i.e ions that do not take part in the reaction are omitted on both sides of the ionic equation.

4. Writing ionic equations Example 1
Step 1
Write word equation and chemical formula.
Silver nitrate + sodium chloride  silver chloride + sodium nitrate
AgNO3 (aq) + NaCl (aq)  AgCl (s) + Na NO3 (aq)

5. Writing ionic equations Example 1
Step 2
Write formula of ions formed
AgNO3 (aq) + NaCl (aq)  AgCl (s) + Na NO3 (aq)
Ag+ (aq) + NO3- (aq) + Na+ (aq) + Cl- (aq)  AgCl (s) + Na+ (aq) + NO3- (aq)
Not able to dissolve in water to form ions

6. Writing ionic equations Example 1
Step 3
Omit spectator ions (NO3- and Na+ appear both sides. Do not take part in the reaction. Can be cancelled)
Ag+ (aq) + NO3- (aq) + Na+ (aq) + Cl- (aq)  AgCl (s) + Na+ (aq) + NO3- (aq)
Ag+ (aq) + Cl- (aq)  AgCl (s)

7. Writing ionic equations Example 2
Step 1
Write word equation and chemical formula.
Sodium hydroxide + hydrochloric acid  sodium chloride + water
NaOH (aq)+ HCl (aq)  NaCl (aq) + H2O (l)

8. Writing ionic equations Example 2
Step 2
Write formula of ions formed
NaOH (aq)+ HCl (aq)  NaCl (aq) + H2O (l)
Na+ (aq) + OH- (aq) + H+ (aq) + Cl- (aq)  Na+ (aq) + Cl- (aq) + H2O (l)
Covalent compound. Does not form ions

9. Writing ionic equations Example 2
Step 3
Omit spectator ions (Na+ and Cl- appear both sides. Do not take part in the reaction. Can be cancelled)
Na+ (aq) + OH- (aq) + H+ (aq) + Cl- (aq)  Na+ (aq) + Cl- (aq) + H2O (l)
H+ (aq) + OH- (aq)  H2O (l)

10. Writing ionic equations Example 3
Step 1
Write word equation and chemical formula.
Sodium carbonate + dilute hydrochloric acid  sodium chloride + water + carbon dioxide
Na2CO3 (aq)+ 2HCl (aq)  2NaCl (aq) + H2O (l) + CO2 (g)

11. Writing ionic equations Example 3
Step 2
Write formula of ions formed
Na2CO3 (aq)+ 2HCl (aq)  2NaCl (aq) + H2O (l) + CO2 (g)
2Na+ (aq) + CO3- (aq) + 2H+ (aq) + 2Cl- (aq)  2Na+ (aq) + 2Cl- (aq) + H2O (l) + CO2 (g)

12. Writing ionic equations Example 3
Step 3
Omit spectator ions (Na+ and Cl- appear both sides. Do not take part in the reaction. Can be cancelled)
2Na+ (aq) + CO3- (aq) + 2H+ (aq) + 2Cl- (aq)  2Na+ (aq) + 2Cl- (aq) + H2O (l) + CO2 (g)
2H+ (aq) + CO3- (aq)  CO2 (g) + H2O (l)

13. QUESTION 1 Magnesium + sulfuric acid  magnesium sulfate + hydrogen
Write balanced chemical equations and then the ionic equations (with state symbols) for the following questions.
1 Magnesium + sulfuric acid  magnesium sulfate + hydrogen
2 Sodium hydroxide + nitric acid  Sodium nitrate + water

14. QUESTION
Write balanced chemical equations and then the ionic equations (with state symbols) for the following questions.
3 Magnesium oxide + hydrochloric acid  Magnesium chloride + water
4 Silver nitrate solution + potassium iodide solution  silver iodide (AgI is insoluble) + potassium nitrate

15. Answers in red box
(take a peek only after you’ve done the questions in your notes. Your integrity counts!)

16. 1. Magnesium + sulfuric acid  magnesium sulfate + hydrogen
Mg (s) + H2SO4 (aq)  MgSO4 (aq) + H2 (g)
Mg (s) + 2H+ (aq) + SO42- (aq)  Mg2+ (aq) + SO42- (aq) + H2 (g)
Mg (s) + 2H+ (aq)  Mg2+ (aq) + H2 (g)

17. 2. Sodium hydroxide + nitric acid  Sodium nitrate + water
NaOH (aq) + HNO3 (aq)  NaNO3 (aq) + H2O (l)
Na+ (aq) + OH- (aq) + H+ (aq) + NO3- (aq)  Na+ (aq) + NO3- (aq) + H2O (l)
OH- (aq) + H+ (aq)  H2O (l)

18. 3. Magnesium oxide + hydrochloric acid  Magnesium chloride + water
MgO (s) + 2HCl (aq)  MgCl2 (aq) + H2O (l)
MgO (s) + 2H+ (aq) + 2Cl- (aq)  Mg2+ (aq) +
2Cl- (aq) + H2O (l)
MgO (s) + 2H+ (aq)  Mg2+ (aq) + H2O (l)

19. Ag+ (aq) + I- (aq)  AgI (s)
4. Silver nitrate + potassium iodide  silver iodide + potassium nitrate
AgNO3 (aq) + KI (aq)  AgI (s) + KNO3 (aq)
Ag+ (aq) + NO3- (aq) + K+ (aq) + I- (aq) 
AgI (s) + K+ (aq) + NO3- (aq)
Ag+ (aq) + I- (aq)  AgI (s)