Chapter 6: Chemical Reactions

 Identify and write equations for gas evolution reactions.

 Gases that are commonly produced are carbon dioxide, hydrogen cyanide, sulfur dioxide, ammonia, and hydrogen sulfide.  2HI(aq) + Li 2 S(aq) → H 2 S(g) + 2LiI(aq)

 Many gas producing reactions occur when a product from a double displacement reaction decomposes.  HNO 3 (aq) + Na 2 CO 3 (aq) → H 2 CO 3 (aq) + NaNO 3 (aq) H 2 O and CO 2

 Begin by writing a skeletal equation that includes the reactants and products that form when the cation of each reactant combines with the anion of the other.  HNO 3 (aq) + Na 2 CO 3 (aq) → H 2 CO 3 (aq) + NaNO 3 (aq)

 You must recognize that H 2 CO 3 (aq) decomposes into H 2 O(l) and CO 2 (g) and write the corresponding equation.  HNO 3 (aq) + Na 2 CO 3 (aq) → H 2 O (l) + CO 2 (aq) + NaNO 3 (aq)

 Finally, balance the equation.  2HNO 3 (aq) + Na 2 CO 3 (aq) → H 2 O (l) + CO 2 (aq) + 2NaNO 3 (aq)

 Write chemical, complete ionic, and net ionic equations for each of the following reactions.  Perchloric acid reacts with aqueous potassium carbonate, forming carbon dioxide gas and water.

 Nitric acid reacts with aqueous sodium carbonate.

 Aqueous hydrobromic acid reacts with aqueous potassium sulfite.