CHEMICAL REACTIONS New Topic In a chemical reaction the substances on the left of the arrow are the reactants and on the right are the products. Hydrogen + Oxygen -> Water Reactants react together and Products are produced after the reaction REACTANTS AND PRODUCTS In a chemical reaction nothing is created or destroyed. The atoms are simply rearranged LAW OF CONSERVATION OF MASS Sodium + water -> sodium hydroxide + hydrogen A word equation summarises the equation Reactants _________________ Products __________________ A WORD EQUATION 2Na + 2H2o -> 2NaOH + H2 This tells formulas of all the substances involved and the ratio in which they react Nothing has been created or destroyed, only the atoms have been re-arranged A CHEMICAL EQUATION Reacting Hydrogen and Oxygen 1) write out the word equation Hydrogen + Oxygen -> Water 2) write the simplified chemical equation H2 + O2 -> H2O 3) we need the same number of atoms on each side of the arrow WRITING CHEMICAL EQUATIONS Types of atom – Number of atom – Balancing it BALANCING THE EQUATION Question 5 – page 159 COMPLETE