Focus Question: What are chemical equations?

Mixtures and Solutions

Chemical Reactions 3-3

Questions from Chemical Formulas• Use chemical formulas to write the

equation for the reaction between carbon and oxygen

• C + O2 CO2

• Use chemical formulas to write the equation for the reaction between oxygen and hydrogen

• 2H2 + O2 2H2O

• What happens to hydrochloric acid when it reacts with baking soda?

Reaction Review• What were the reactants that produced

the fizzing in Cup 1?

• What were the products from Cup 1?

• Atoms rearrange during reactions. No atoms are destroyed and not atoms are created, just rearranged.

Chemical Equations• A chemical equation is a diagram of a

chemical reaction. The equation shows the reactants on the left side of an arrow and the products on the right side of the arrow.

• The number of atoms on one side of the equation has to equal the number of atoms on the other side of the equation.

Reactant Sheets• Bag of atom disks that are small

versions of the magnetic ones on the board.

• Work in pairs with a set of atom disks to explore how reactant atoms can rearrange to form product molecules.

Water Reaction• The first reaction has two reactants, one

oxygen molecule and two hydrogen molecules. Work with partner to complete the equation to show how the reactants rearrange to form the substance water, H2O.

• Start by putting oxygen and hydrogen atom disks from your set on top of the oxygen and hydrogen circles on the Reactant Sheet.

• Make product molecules on the product side of the equation by moving the atom disks to the product side of the arrow.

• Make sure no atoms are left over.

Calcium-Chloride Reaction• Look at reaction 2 on the Reactant

Sheet.

• It has two molecules of baking soda and one molecule of calcium chloride as reactants.

• Work with your partner, using the atom disks, to product the products you observed in the experiment.

• You must account for all atoms. No atoms can be left over.

Chemical Equations Worksheet

• Identify and represent four reactions– First using drawings of atom disks– Then using chemical formulas

• Complete Response Sheet - Fizz Quiz

Vocabulary• Chemical Equation - used by scientists

to represent chemical reactions.

Content• What does a chemical equation tell

you?

• How the atoms in the reactants and products rearrange during a chemical reaction.

• Your questions?

• Homework - read “Reactants=Products” page 34- and answer questions