1. Chemical Equations Chapter 11 Notes

2. Balanced Equation 2 NaCl + F 2  2 NaF + Cl 2 ReactantsProducts Yields is the “equals” Coefficient used to balance the equation Subscript – formula, can NOT be changed!

3. Symbols You Will See reaction is reversible (s)solid (l) liquid (g) gas (aq) aqueous – dissolved in water

4. Symbols You Will See heat added to the reaction Catalyst is added – speeds up the reaction without being used heat Pt Symbol of the catalyst

5. WHY? Law of conservation of Mass (or Matter) – no mass or energy can be created or destroyed What you have in the reactants you must have in the products

6. Equations Yesterday we balanced blocks Same number of each color on each side of arrow Do the same process for chemical equations +

7. Writing Formulas from Words Diatomic Molecules – 2 atoms H Cl I F Br O N When these atoms are alone in nature, they must always have a subscript of 2 When these atoms are in a compound, then you CROSS THE CHARGES. All other elements when by themselves can be “plain”

8. Rules You Need to Follow: Think of polyatomic ions that are present on both sides of the reaction as one unit. Put coefficients IN FRONT OF the formula – DO NOT CHANGE SUBSCRIPTS! DO NOT write a coefficient of 1. Reduce coefficients so they are in the lowest whole-number ratio.

9. Worksheet Writing #1 zinc + lead (II) nitrate yields zinc nitrate + lead ZnPb (NO 3 ) 2  Zn(NO 3 ) 2 ++Pb Balanced!

10. Worksheet Writing #2 Aluminum bromide + chlorine yield aluminum chloride + bromine AlBr 3 +Cl 2  AlCl 3 +Br 2 2233

11. Worksheet Writing #3 sodium phosphate + calcium chloride yield calcium phosphate + sodium chloride Na 3 PO 4 ++CaCl 2  Ca 3 (PO 4 ) 2 NaCl263

12. Worksheet Writing #4 Potassium chlorate when heated yield Potassium chloride + Oxygen gas KClO 3  KCl+O2O2 232