1. Chemical Equations
Unit 5.1

2. Baking Soda and Vinegar Reaction
NaHCO3 (s) + HC2H3O2(l)  → CO2(g) +  H2O(l) + NaC2H3O2 (aq )

3. Chemical Equations
Chemical Equation- describes a chemical change using symbols; the reactant side is on the left, the product side is on the right
Reactants - substances that react in a chemical reaction.
Products - new substances that are produced in a chemical reaction.
Coefficient – tells you how many molecules of a substance there is

4. What’s a molecule?
Molecule: the smallest unit of a substance that still keeps the physical and chemical properties of that substance
Describe the following...
CF4 = 2 elements, 5 atoms, 1 molecule, pure substance, compound
H2 = 1 element, 2 atoms, 1 molecule, pure substance
2HCl = 2 elements, 4 atoms, 2 molecules, pure substance, compound
H2O + NaCl (salt water) = 4 elements, 5 atoms, 2 molecules, mixture, 2 compounds

5. Symbols You Will See When Writing Chemical Equations
+ : plus
(s) : solid
(l) : liquid
(aq) : aqueous- means dissolved in water
(g) : gas
→ : yields or produces
the reaction is reversible

6. Symbols You Will See When Writing Chemical Equations
The element symbol above the arrow indicates a catalyst was used to change the reactants.
A catalyst is something that
1. Speeds up a chemical reaction
2. Lowers the activation energy- the energy required to start a chemical reaction
Other Common Catalysts
the reactants are changed by heat
the reactants are changed by light
the reactants are changed by electricity

7. Graph Showing the Change in Energy in a Chemical Reaction

8. Practice… Describe the following reaction by…
Listing how many atoms of each element are on the reactant and the product side
Writing a sentence describing the entire reaction