1. 9 th Grade Science Chapter 24 Section 1

2. Chemical Changes  Chemical change: Atoms change bonds and form new materials  Chemical reaction: Process of chemical change Reactants: Products: Written as chemical equation ○ Reactants  Products

3. Law of Conservation of Mass  Antoine Lavoisier (1743 – 1794) Tested great many experiments Mass of products equals mass of reactants Law: matter cannot be created or destroyed in a chemical reaction Matter (atoms) is just rearranged in reaction

4. Chemical Equation  Equation describes what happens in chemical reaction  Uses formulae and coefficients to indicate type and amount of reactants and products  Example: nickel (II) chloride dissolved in water reacts with sodium hydroxide dissolved in water to produce solid nickel (II) hydroxide and sodium chloride dissolved in water