1. CHAPTER 8 Section 1

2. Chemical Reaction – the process by which one or more substances are changed into one or more different substances Reactants – the original substances Products – the resulting substances Chemical Equation – represents with symbols and formulas the identity of the substances and the relative amounts of the reactants and products in a chemical reaction.

3. Indications of a Chemical Reaction Heat and Light  Match Gas produced  HC 2 H 3 O 2 and NaHCO 3 Formation of a Precipitate  Precipitate (ppt) – a solid produced in a chemical reaction  NaCl and AgNO 3 Color Change  NaOH and Phenolphthalein

4. Characteristics of Chemical Equations The equation must represent known facts The equation must contain correct formulas for reactants and products The law of conservation of mass must be satisfied  Coefficient – a small whole number that appears in front of a formula in a chemical equation

5. Equations Word Equation- an equation in which the products and reactants in a chemical reaction are represented by words Methane + oxygen → carbon dioxide + water → - yields, produce, or form

6. Equations Formula equation – represents the reactants and products of a chemical reaction by their symbols or formulas CH 4 (g) + O 2 (g) → CO 2 (g) + H 2 O(g) (g) represents state

7. → - yields ↔ - reversible rxn (s) - solid (g) - gas (l) - liquid (aq) - aqueous (dissolved in water) → - rxn heated, other specific conditions examples Symbols Δ

8. Law of Conservation of Mass and Formula Equations CH 4 (g) + O 2 (g) → CO 2 (g) + H 2 O(g) not balanced CH 4 (g) + 2O 2 (g) → CO 2 (g) + 2H 2 O(g) balanced

9. Practice CS 2 (l) + O 2 (g) → CO 2 (g) + SO 2 (g) NaCl(aq) + AgNO 3 (aq) →NaNO 3 (aq) + AgCl(s) PbCl 2 (aq)+Na 2 CrO 4 (aq) → PbCrO 4 (s) +NaCl(aq)

10. Practice CS 2 (l) + 3O 2 (g) → CO 2 (g) + 2SO 2 (g) NaCl(aq) + AgNO 3 (aq) →NaNO 3 (aq) + AgCl(s) PbCl 2 (aq) + Na 2 CrO 4 (aq) → PbCrO 4 (s) + 2NaCl(aq)

11. Balancing equations Write formula equations – make sure you have correct formulas Balance elements that appear only once on each side Balance polyatomic ions as single units (in most cases) Balance H and O last Examples

12. Magnesium and hydrochloric acid react to produce magnesium chloride and hydrogen. Nitric acid reacts with magnesium hydroxide to produce magnesium nitrate and water When copper reacts with silver nitrate, the products are copper(II) nitrate and silver The reaction between iron(III) oxide and carbon monoxide gas produces iron and carbon dioxide.

13. Practice Solid calcium reacts with solid sulfur to produce solid calcium sulfide Hydrogen gas reacts with fluorine gas to produce hydrogen fluoride gas Solid aluminum metal reacts with aqueous zinc chloride to produce solid zinc metal and aqueous aluminum chloride