9/8/11 As you come in… Turn in ionic compound sheet and page 50, 19 & 20. Have out flashcards. Pick up 3 handouts. Objectives I can describe the processes of forming an aqueous solution and a precipitate. I can define polarity and give examples that show water is a polar molecule. Catalyst Using page 40 of your book, name the following compounds. Fe3P2 2. K3PO4 Give the formula for the following compounds 3. Cadmium Nitrate 4. Copper (II) Sulfite

C. Polarity 1. electrons are not evenly distributed around the molecule a. molecules have positive parts and negative parts b. these + and – parts are attracted to their opposites in other molecules 2. Water is a polar molecule a. Animation b. video

D. Dissolving ionic compounds 1. Ionic compounds are… a D. Dissolving ionic compounds 1. Ionic compounds are… a. made up of anions (-) and cations (+) b. arranged in a 3D network called a crystal c. held together by positive and negative attractions between ions d. when put in water, disassociate (cations and anions separate) i. now an aqueous (aq) solution 2. Dissolving animation

NaCl + H2O H2O + Na+ Cl-

RULES FOR COUNTING ATOMS SUBSCRIPTS only refer to the atom that they are BEHIND. For example… H2S There are TWO atoms of HYDROGEN and only ONE atom of SULFUR.

PARENTHESES 2. If elements or compounds are inside of PARENTHESES, then the SUBSCRIPT behind the parentheses applies to everything inside. Ba(OH)2 ATOMS OF BARIUM: ATOMS OF OXYGEN: ATOMS OF HYDROGEN: 1 2 2

COEFFICIENTS 3. COEFFICIENTS apply to the entire compound. You MULTIPLY the coefficients and SUBSCRIPTS. 2 H2S ATOMS OF HYDROGEN: ATOMS OF SULFUR: 4 2 IF THERE ISN’T A SUBSCRIPT BEHIND AN ELEMENT, ASSUME THERE IS ONLY ONE ATOM OF THAT ELEMENT!

THIS COULD BE A LITTLE TRICKY… Ca3(PO4)2 Atoms of Calcium: Atoms of Phosphorus: Atoms of Oxygen: 3 2 8 Al2(SO4)3 Atoms of Aluminum: Atoms of Sulfur: Atoms of Oxygen: 2 3 12

What about this BAD BOY??? 2Ca3(PO4)2 Atoms of Calcium: Atoms of Phosphorus: Atoms of Oxygen: 6 4 16

Balancing Equations Law of Conservation of Matter: In a chemical reaction, matter cannot be created or destroyed The number of atoms of each type of element must be the same on each side of the equation

Balancing Equation H2 + O2 H2O Count the atoms on each side. Reactant side: 2 atoms H and 2 atoms O Product side: 2 atoms H and 1 atom O

Balancing Equations H2 + O2 H2O Just like ions, these molecules cannot be changed. The subscripts cannot change, so adjust the number of molecules by changing the coefficients.

Balancing Equations H2 + O2 2H2O Reactants: 2 atoms of H and 2 atoms of O Products: 4 atoms of H and 2 atoms of O H is no longer balanced!

Balancing Equations 2H2 + O2 2H2O Reactant side: 4 atoms of H and 2 atoms of O Product side: 4 atoms of H and 2 atoms of O It’s Balanced!

Nitrogen + hydrogen ammonia Balancing Equations N2 + H2 NH3 Nitrogen + hydrogen ammonia Count atoms. Reactants: 2 atoms N and 2 atoms H Products: 1 atom N and 3 atoms of NH3

Balancing Equations N2 + H2 2NH3 Nothing is balanced. Balance the nitrogen by placing a coefficient of 2 in front of the NH3. N2 + H2 2NH3

Balancing Equations N2 + 3H2 2NH3 Hydrogen is not balanced. Place a 3 in front of H2. Reactant side: 2 atoms N, 6 atoms H Product side: 2 atoms N, 6 atoms H N2 + 3H2 2NH3

Balancing Equations Ca3(PO4)2 + H2SO4 CaSO4 + H3PO4 In this equation, the ion groups do not break up. Instead of counting individual atoms, ion groups may be counted. Ca3(PO4)2 + H2SO4 CaSO4 + H3PO4

Balancing Equations Ca3(PO4)2 + H2SO4 CaSO4 + H3PO4 Reactants: Ca2+ – 3, PO43- - 2, H+ – 2, SO42+ - 1 Products: Ca2+ - 1, SO42- - 1, H+ - 3, PO43- - 1

Balancing Equations Ca3(PO4)2 + H2SO4 3CaSO4 + H3PO4 Balance the metal first by placing a coefficient of 3 in front of CaSO4. Products: Ca – 3 atoms, SO42- - 3 groups Ca3(PO4)2 + H2SO4 3CaSO4 + H3PO4

Balancing Equations Ca3(PO4)2 + 3H2SO4 3CaSO4 + H3PO4 Three sulfate groups are needed on the reactant side so place a coefficient of 3 in front of H2SO4. 3H2SO4 gives 6 H+ and 3 SO42-. Neither phosphate nor calcium is balanced. Ca3(PO4)2 + 3H2SO4 3CaSO4 + H3PO4

Balancing Equations A coefficient of 2 placed in front of H3PO4 which balances both hydrogen and phosphate. Ca3(PO4)2 + 3H2SO4 3CaSO4 + 2H3PO4

Balancing Equations Balancing hints: Balance the metals first. Balance the ion groups next. Balance the other atoms. Save the non ion group oxygen and hydrogen until the end. Use the lowest possible coefficients!