1. Chapter 11.1 Pages 321-324

2. Chemical Reactions Occur everywhere and all the time Rusting iron, Break down of glucose, Exploding hydrogen Evidence of chemical reactions Color change pH change Energy change (gets hotter or colder) Precipitate formation Gas formation

3. Chemical Equations A representation of a chemical reaction Example: H 2 + O 2  2H 2 O Reactants = H 2 + O 2 Products = 2H 2 O  = Yields or Produces

4. Chemical Sentences and Word Equations Names of elements or compounds are used to indicate substances and the amounts used in a reaction Example: H 2 + O 2  2H 2 O Chemical Sentence One molecule of hydrogen gas reacts with one molecule of oxygen gas to produce (yield) two molecules of water.

5. Chemical Sentences and Word Equations Names of elements or compounds are used to indicate substances and the amounts used in a reaction Example: H 2 + O 2  2H 2 O Word Equation Hydrogen gas + Oxygen gas  Water

6. Practice Fe (s) + O 2(g)  Fe 2 O 3(s) What are the products? What are the reactants? What is the chemical sentence? What is the word equation?  H2O H2O

7. Other Symbols to know… (s) = substance is in a solid state (l) = substance is in a liquid state (aq) = aqueous solution - substance is dissolved in water (g) = substance is in a gaseous state

8. Other Symbols to know… + = used to separate two reactants or two products  = separates reactants from products  = for reversible reactions  or  = indicate that heat is used in the reaction  = A formula (could be any – in this case platinum) indicates it is used as a catalyst Pt  Heat

9. Catalyst A substance that speeds up a chemical reaction but is not used in the reaction Example: Fe (s) + O 2(g)  Fe 2 O 3(s) What are the catalysts in this reaction? What phase state is each substance in for this reaction?  H2O H2O