Compounds, Formulae and Equations

1. Compounds, Formulae and Equations Balancing Compounds Equations

2. What is a general equation? • A general equation in chemistry is like a general equation in mathematics: • - It shows a general rule • - A + B = C • In chemistry however, we write this in terms of reactants and products: • - Reactants  Products • Examples • - Acid + Base  Salt + Water • - Acid + Oxide  Salt + Water • - Acid + Hydroxide  Salt + Water • - Acid + Carbonate  Salt + Water + Carbon Dioxide

3. What is a word equation? • A word equation is a specific general equation, in that the reactants and the products must be specified: • - Hydrochloric Acid + Sodium Hydroxide  Sodium Chloride + Water • - Sulfuric Acid + Aluminium Oxide  Aluminium Sulfate + Water • - Nitric Acid + Lithium Hydroxide  Lithium Nitrate + Water • - Phosphoric Acid + Calcium Carbonate  Calcium Phosphate + Water + Carbon Dioxide

4. What is a symbol equation? • A formula equation is one that uses symbols to (apparently) abbreviate the equations: • - HCl + NaOH NaCl + H2O • - H2SO4 + Al2O3  Al2(SO4)3 + H2O • - HNO3 + Be(OH)2  Be(NO3)2 + H2O • - H3PO4 + CaCO3  Ca3(PO4)2 + H2O + CO2

5. What is a balanced equation? • A balanced equation is a symbol equation whose atoms in the reactants and products equal. • When a symbol equation has been written, you can only change the number of atoms/compounds (big numbers before the atom/compound) not the compounds themselves (small numbers within the compound) . • - HCl + NaOH NaCl + H2O (already balanced!) • - 3H2SO4+ Al2O3  Al2(SO4)3 + 3H2O • - 2HNO3+ Be(OH)2  Be(NO3)2 + 2H2O • - 2H3PO4+ 3CaCO3 Ca3(PO4)2 + 3H2O + 3CO2

6. Balanced equations and balanced formulae are not the same thing!!!

7. Balanced Formula • … are balanced compounds. • (ionic or covalent)

8. Balanced equations • … have reactants and products.