Introduction to Chemical Equations

1. Introduction to Chemical Equations Chemistry Ms. Piela

2. Chemical Equation Background Reactants – Starting substances in a chemical reaction Products – Substances formed in a chemical reaction Often, physical states are included for added information….

3. Chemical Equation Background

4. Chemical Equation Background • Coefficients - numbers placed in front of molecules that indicate how many take part in a reaction • Example: O2 + 2 H2→2 H2O

5. 5 Main Types of Chemical Reactions A + B → AB 6 Fe (s) 2 O2(g) 2 Fe3O2(s) • Synthesis Reactions • Reaction in which two or more substances combine • Basic Form: • Example: + →

6. 5 Main Types of Chemical Reactions AB → A + B 2 H2O (l) 2 H2(g) O2(g) • Decomposition Reactions • Single compound which breaks down to form two or more simpler compounds • Basic Form: • Example: → +

7. 5 Main Types of Chemical Reactions A + B X → A X + B 2 Al (s) 3 2(aq) Cu Cl 2 3(aq) Al Cl 3 Cu (s) • Displacement Reactions • Sometimes called “single displacement” or “single replacement” • Single element reacts with a compound and displaces another element • Basic Form: • Example: + →+

8. 5 Main Types of Chemical Reactions A X + B Y → B X + A Y 3 2(aq) Cu Cl 2 4(aq) Na3 PO 6 Na Cl Cu3 (PO4)2 (s) • Double Displacement Reactions • Two atoms or ions exchanged between to compounds • Basic Form: • Example: +→+

9. 5 Main Types of Chemical Reactions CxHyOz + O2 → CO2 + H2O 2 C3H7OH (l) 9 O2(g) 3 CO2 (g) 4 H2O (g) • Combustion • Oxidation reaction in which heat is released • Basic Form: • Example: + →+