2. Exercise 1 (p. 72) 7.82 g of sulphur dioxide (SO 2 ) and 8.4 g hydrogen sulphide (H 2 S) react to form octasulphur (S 8 ) and water (H 2 O). (a)Write the chemical equation and balance it ? (b) Calculate the amount of sulphur (S) produced in this experiment in grams ? Data: M(C) = 12 g/mol; M(O) = 16 g/mol, M(H) = 1 g/mol and M (S) = 32 g/mol Solution (p. 72 and 74).

3. Exercise 1 (p. 72) Solution (Continue).

4. Exercise 2 (p. 72) In a chemical reaction, 1.54g of Chromium nitrate Cr(NO 3 ) 3, dissolved in 120 mL of 0.1M H 2 S to yield Chromium sulfide Cr 2 S 3 and HNO 3. (a) Write and balance the chemical equation of the reaction? (b) Calculate the mass of the excess reactant? Data: M(Cr) = 52 g/mol; M(S) = 32 g/mol; M(N)=14 g/mol Solution

5. Exercise 4 (p. 72) 25.0 g benzene, C 6 H 6 reacts with nitric acid HNO 3 (in excess) resulted in 21.4g of nitrobenzene C 6 H 5 NO 2 and water (H 2 O). (a) Write and balance the chemical equation of the reaction? (b) Calculate the percentage yield of the reaction? Data: M(C) = 12 g/mol; M(O) = 16 g/mol; M(N)=14 g/mol Solution

6. Exercise 5 (p. 72, exercise 2)) (a) Phenolphthalein (C 20 H 14 O 4 ) can be prepared by the reaction of phthalic anhydride (C 8 H 4 O 3 ) with phenol (C 6 H 6 O). Write and balance the chemical equation of the synthesis of phenolphthalein? (b) If 5.0 g of pure phenolphthalein is isolated from a reaction mixture consisting of 10.0 g of phthalic anhydride and 20.0 g of phenol, what are the limiting reactant and the percentage yield ? Data: M(C) = 12 g/mol; M(O) = 16 g/mol; M(H)=1.0 g/mol Solution

7. Exercise 6 (p. 87, exercise 1) 25.0 mL of a concentrated aqueous ammonia solution (14.8M) is diluted to 500.0 mL. What is the molarity of the diluted solution ? Solution

8. Exercise 6 (p. 87, exercise 1) Aluminium (Al) reacts with sulfuric acid (H 2 SO 4 ) to yield aluminium sulphate Al 2 (SO 4 ) 3 and hydrogen gas (H 2 ) ? (a)Write and balance the chemical equation of the reaction? (b) Calculate the volume of 0.1 M acid sulfuric to react completely with 1 g of aluminum? Data: M(Al) = 27 g/mol; M(S) = 32 g/mol; Solution

9. Exercise 7 (p. 89, exercise 10) The silver nitrate (AgNO 3 ) in 20.0 mL of a certain solution was allowed to react with sodium chloride according to the following reaction: AgNO 3 (aq) + NaCl (aq) → AgCl (s) + NaNO 3 (aq). The AgCl was collected, dried and weighed to give 0.2867g AgCl. What was the molarity of the original AgNO 3 solution ? Data: M(Ag) = 108 g/mol; M(Cl) = 35.5 g/mol; M(Na) = 23 g/mol. Solution