1. Balancing Equations

2. Law of Conservation of Mass In any chemical reaction, the total mass of the reactants equal the mass of the products (Or, what goes in must come out!) Copy to notes

3. Types of Reactions • 5 types of chemicals reactions: • Synthesis reactions • Decomposition reactions • Single Displacement reactions • Double Displacement reactions • Combustion reactions Copy to notes

4. States of Elements • Solid • Represented by (s) • Liquid • Represented by (l) • Gas • Represented by (g) • Aqueous (dissolved in water) • Represented by (aq) Copy to notes

5. Balancing Equations ___ Al(s) + ____Br2(l)  ___ AlBr3(s) Copy to notes

6. Balancing Equations ___ Ca3P2 + ____Na  ___Ca + ___ Na3P(s) __ LiOH(aq) + __H2(g)  ___Li(s) + ___ HOH(l) Copy to notes

7. Symbols used in Chemical Reactions + used to separate reactants or products  yield sign: used to separate reactants and products Copy to notes

8. Chemical Reactions • Rules for balancing equations: • The law of conservation of mass much be followed • Each side of the equation must have the same number of atoms • Add coefficients to reactants and products (ALWAYS IN WHOLE NUMBERS!) Copy to notes

9. Rules for Balancing Equations __BaCl2(aq) + __H3PO4(aq)  __Ba3(PO4)2(s) + __HCl(aq) Rules: Be sure you have the correct formulas for reactants and products If the same complex ion appears on both sides, then treat is as one group Check for 2 to 3 ratios – do them first! Balance highest (noncomplex ion) #’s next Save single elements for last Check all numbers once you’re done…. Copy to notes