predict the products & write the balanced equation including physical states, if no reaction give reasons why *classify the reaction type.?

Question

23. Aqueous lithium sulfide is added to chloric acid.

24. Aqueous iron(III) chloride and aqueous sodium carbonate are mixed.

25. Liquid naphthalene (C10H8) burns.

Answer 1

Li₂S(aq) + 2HClO₃ (aq) --> 2LiClO₃ (aq) + H₂S (aq) Double replacement

2FeCl₃ (aq) + 3Na₂CO₃ (aq) --> Fe₂(CO₃)₃ (s) + 6NaCl (aq) Double replacement

C₁₀H₈ (l) + 12O₂ (g) --> 10CO₂ (g) + 4H₂O (l) Combustion

For each equation, you must know the ionic charges and the charges of polyatomic ions in order to form products where the total charge of the compound is neutral. Li +1 ClO₃ -1 ; H+1 S-2 Since the charges do not cancel out, you must "swap and drop" to get the proper formula of H₂S.

In the second equation, you must use a solubility chart to see that Carbonate ions are not soluble with Iron ions so that is why it forms a precipitate. Although this is a double replacement reaction, some teachers want to realize that a precipitate is formed and call this a "precipitation" reaction.

The last equation starts with a compound that contains only carbon and hydrogen. These are referred to as hydrocarbons. When hydrocarbons burn, they require oxygen and ALWAYS produce carbon dioxide and water. This is called a combustion reaction.