Balancing Equations Goal Practise balancing and classifying chemical equations. What to Do Answer the questions in each section in the space provided. Balancing Formation Reaction Equations 1. Balance each equation for a formation reaction. (a) K (s) + O 2(g) K 2 O (s) (b) P 4(s) + Cl 2(g) PCl 5(s) (c) Cu (s) + S 8(s) CuS (s) (d) Mg (s) + O 2(g) MgO (s) (e) Fe (s) + O 2(g) Fe 2 O 3(s) (f) P 4(s) + S 8(g) P 2 S 5(s) (g) C (s) + O 2(g) CO (g) (h) N 2(g) + O 2(g) NO 2(g) (i) Li (s) + N 2(g) Li 3 N (s) (j) S 8(s) + O 2(g) SO 2(g) 2. Write a balanced chemical equation to represent each reaction described below. (a) Solid aluminum metal reacts with oxygen gas to form solid aluminum oxide. (b) Metallic zinc combines with elemental sulfur to form zinc sulfide. Balancing Decomposition Reaction Equations 3. Balance each equation for a decomposition reaction. (a) NaCl (s) Na (s) + Cl 2(g) (b) CaBr 2(s) Ca (s) + Br 2(l) (c) CCl 4(l) C (s) + Cl 2(g) (d) NCl 3 (g) N 2(g) + Cl 2(g)
(e) P 4 O 10(s) P 4(s) + O 2(g) (f) Ag 2 O (s) Ag (s) + O 2(g) (g) HCl (aq) H 2(g) + Cl 2(g) (h) KI (s) K (s) + I 2(s) (i) AlCl 3(s) Al (s) + Cl 2(g) (j) CuO (s) Cu (s) + O 2(g) 4. Write a balanced chemical equation to represent each reaction described below. (a) Rubidium oxide decomposes into its elements. (b) Calcium chloride decomposes into its elements. Balancing Single Replacement Reaction Equations 5. Balance each equation for a single replacement reaction. (a) K (s) + H 3 PO 4(aq) K 3 PO 4(aq) + H 2(g) (b) Fe (s) + H 2 S (aq) Fe 2 S 3(s) + H 2(g) (c) Cl 2(g) + MgBr 2(aq) MgCl 2(aq) + Br 2(aq) (d) Cu (s) + Ag 2 CO 3(s) CuCO 3(s) + Ag (s) (e) Br 2(g) + KI (aq) I 2(aq) + KBr (aq) (f) Mg (s) + Zn 3 (PO 4 ) 2(s) Mg 3 (PO 4 ) 2(s) + Zn (s) (g) K (s) + Al(NO 3 ) 3(aq) Al (s) + KNO 3(aq) (h) Ca (s) + H 2 O (l) Ca(OH) 2(s) + H 2(g) (i) Na (s) + H 2 SO 4(s) Na 2 SO 4(aq) + H 2(g) (j) K (s) + H 2 O (l) KOH (aq) + H 2(g)
6. Write a balanced chemical equation to represent each reaction described below. (a) Silver reacts with gold(iii) nitrate. (b) Copper reacts with lead(ii) sulfate. Balancing Double Replacement Reaction Equations 7. Balance each equation for a double replacement reaction. (a) Na 2 SO 4(aq) + BaCl 2(aq) BaSO 4(s) + NaCl (aq) (b) HNO 3(aq) + Ba(OH) 2(aq) H 2 O (l) + Ba(NO 3 ) 2(aq) (c) Na 2 CO 3(aq) + Fe(NO 3 ) 3(aq) Fe 2 (CO 3 ) 3(s) + NaNO 3(aq) (d) CaCl 2(aq) + K 3 PO 4(aq) Ca 3 (PO 4 ) 2(s) + KCl (aq) (e) Al 2 (SO 4 ) 3(aq) + Ba(OH) 2(aq) Al(OH) 3(s) + BaSO 4(s) (f) NaOH (aq) + H 2 SO 4(aq) H 2 O (l) + Na 2 SO 4(aq) (g) Na 3 PO 4(aq) + Ag 2 SO 4 (s) Na 2 SO 4(aq) + Ag 3 PO 4(s) (h) Na 2 CrO 4(aq) + Cu(NO 3 ) 2(aq) NaNO 3(aq) + CuCrO 4(aq) (i) H 3 PO 4(aq) + KOH (aq) H 2 O (l) + K 3 PO 4(aq) (j) Na 2 CO 3(aq) + HNO 3(aq) H 2 CO 3(aq) + NaNO 3(aq) 8. Write a balanced chemical equation to represent each reaction described below. (a) Solutions of sodium hydroxide and hydrochloric acid react. (b) A silver nitrate solution reacts with a sodium chloride solution.
Balancing Combustion Reaction Equations 9. Balance each equation for a combustion reaction. (a) C 2 H 6(g) + O 2(g) CO 2(g) + H 2 O (g) (b) C 3 H 8(g) + O 2(g) CO 2(g) + H 2 O (g) (c) C 6 H 14(g) + O 2(g) CO 2(g) + H 2 O (g) (d) C 8 H 18(g) + O 2(g) CO 2(g) + H 2 O (g) (e) C 2 H 2(g) + O 2(g) CO 2(g) + H 2 O (g) (f) C 2 H 4(g) + O 2(g) CO 2(g) + H 2 O (g) (g) ZnS (s) + O 2(g) ZnO (s) + SO 2(g) (h) CH 3 NO 2(l) + O 2(g) CO 2(g) + H 2 O (g) + NO 2(g) (i) NH 3(g) + O 2(g) NO 2(g) + H 2 O (g) (j) C 2 H 5 SH (g) + O 2(g) CO 2(g) + H 2 O (g) + SO 2(g) 10. Write a balanced chemical equation to represent each reaction described below. (a) Candle wax, C 25 H 52, is burned to produce carbon dioxide and water. (b) Sucrose, C 12 H 22 O 11, is burned to produce carbon dioxide and water.
Classifying and Balancing Equations 11. Classify each reaction as a formation (F), decomposition (D), single replacement (SR), double replacement (DR), or combustion (C) reaction. Then balance each equation. Reaction Classification Li (s) + AlCl 3(aq) Al (s) + LiCl (aq) NH 3(g) N 2(g) + H 2(g) K (s) + Br 2(l) KBr (s) C 10 H 22(l) + O 2(g) CO 2(g) + H 2 O (g) NH 4 OH (aq) + H 2 CO 3(aq) H 2 O (l) + (NH 4 ) 2 CO 3(aq) H 2 O (l) H 2(g) + O 2(g) Al (s) + Cl 2(g) AlCl 3(s) Zn (s) + SnF 4(aq) Sn (s) + ZnF 2(aq)