Chapter 6: Chemical Reactions

 Determine if a compound is soluble.

 A compound is soluble in a particular liquid if it dissolves in that liquid.  A compound is insoluble if it does not dissolve in the liquid.

 An aqueous solution is a homogeneous mixture of a substance with water.  When ionic compounds dissolve in water, they usually dissociate into their component ions.

NaCl(s) NaCl(aq)

 A sodium chloride solution, NaCl(aq), does not contain any NaCl units.  Only dissolved Na + ions and Cl − ions are present.  Substances (such as NaCl) that completely dissociate into ions in solution are called strong electrolytes.

 Pure water does not conduct electricity.  Ions in a sodium chloride solution conduct electricity, causing the bulb to light.

AgNO 3 (s) AgNO 3 (aq)

 AgNO 3 (aq) is a strong electrolyte solution.  When compounds containing polyatomic ions such as NO 3 − dissolve, the polyatomic ions dissolve as intact units.

AgCl(s)

 Not all ionic compounds dissolve in water.  AgCl does not dissolve in water.  It does not dissolve into independent ions.

 A compound is soluble in a particular liquid if it dissolves in that liquid; a compound is insoluble if it does not dissolve in the liquid.  For ionic compounds, empirical rules of solubility have been deduced from observations of many compounds.

Soluble CompoundsExceptions NO 3 -, C 2 H 3 O 2 - Li +,Na +, K +, NH 4 + Cl -, Br -, I - Except those containing Ag +, Hg 2 2+, Pb 2+ SO 4 2- Except those containing Ba 2+, Ca 2+, Pb 2+, Sr 2+ Will dissolve in waterWill NOT dissolve in water

 For example:  Ca(NO 3 ) 2 is soluble  LiBr is soluble  Hg 2 Cl 2 is insoluble  CaSO 4 is insoluble

Insoluble Compounds Exceptions S 2- Except those containing Li +, Na +, K +, NH 4 + Ca 2+, Ba 2+, Sr 2+ CO 3 2-, PO 4 3- Except those containing Li +, Na +, K +, NH 4 + OH - Except those containing Li +, Na +, K +, NH 4 + Those containing Ca 2+, Sr 2+, Ba 2+ are slightly soluble Will dissolve in water Will NOT dissolve in water

 For example:  Al 2 S 3 is insoluble  CaCO 3 is insoluble  Pb(OH) 2 is insoluble  K 2 S is soluble  Na 3 PO 4 is soluble  NH 4 OH is soluble

 Use the solubility rules to predict which of the following substances are likely to be soluble in water:  Aluminum nitrate  Magnesium chloride  Rubidium sulfate  Nickel (II) hydroxide  Lead (II) sulfide  Magnesium hydroxide  Iron (III) phosphate  Silver bromide