Presentation on theme: "Solubility Rules and Precipitation Reactions. Not all ionic compounds dissolve! Instead of doing experiments all the time to see which ones will dissolve,"— Presentation transcript:
Not all ionic compounds dissolve! Instead of doing experiments all the time to see which ones will dissolve, we use The solubility rules.
Solubility Rules 1.All nitrates (NO 3 - ) are soluble. 2.All ammonium (NH 4 + ) or alkali (Li +, Na +, K +, Rb +, Cs +, Fr + ) compounds are soluble. 3.All carbonates (CO 3 2- ), phosphates (PO 4 3 - ) and hydroxides (OH - ) are insoluble except with the cations in Rule #2. 4. All chlorides (Cl - ), bromides (Br - ), and iodides (I - ), are soluble except with Ag +, Pb 2+, or Hg +. 5. All sulphates (SO 4 2- ) are soluble except with Ca 2+, Sr 2+, Ba 2+, Ra 2+, Pb 2+,
Which of the following are soluble in water? a.SrSO 4 b.NaNO 3 c.PbCl 2 Not soluble soluble Not soluble
Precipitation Reactions When a solid doesn’t dissolve it is called insoluble. A solid that forms when two solutions are mixed is called a precipitate.
Predict the products of the following reaction: (if no solid precipitate is formed, there is no reaction) Pb(NO 3 ) 2 (aq) + KI (aq) Pb(NO 3 ) 2 (aq) + 2KI (aq) PbI 2 (s) + 2KNO 3 (aq) We know it is a solid precipitate because it is insoluble according to the solubility rules.
A picture of the reaction: Pb 2+ NO 3 - Because K + and NO 3 - remain dissolved, they are called spectator ions and are not included in the net ionic equation. Net Ionic Equation Pb 2+ (aq) + 2I - (aq) PbI 2 (s) NO 3 - K+K+ I-I- K+K+ PbI 2(s)
Net Ionic Equation Write the balanced chemical and net ionic equation for: Na 2 CO 3 (aq) + CaCl 2 (aq) Step 1: Write the balanced chemical equation Na 2 CO 3 (aq) + CaCl 2 (aq) CaCO 3 (s) + 2NaCl (aq) Step 2: Remove the spectator ions (those that are soluble). Ca 2+ (aq) + CO 3 2- (aq) CaCO 3 (s) Insoluble precipitate