Bell Ringer
 Find the empirical formula for a 40.0 gram compound
that contains 8 grams of calcium and the rest bromine.
 Find the molecular formula of a compound whose
empirical formula is OH. The compound has a formula
mass of 34.00 g/mol and consists of 7.92 grams of O
and 1.44 grams of H.
 Balance this equations:
P4 + H2 = PH3
Mr. Schlamb
Grade Yourself Quiz
 What do the following symbols mean? You can answer
in your notes or bell ringers.
(s)
(l)
(g)
(aq)
What is on the left side of an equation
What is on the right side of an equation
Answers
 Solid
 Liquid
 Gas
 Aqueous (dissolved)
 Yields
 Indicates a reversible reaction (used in place of yields)
 Reactants
 Products
Why Balance
 The equations must represent known facts
 The equation must contain the correct formulas for
the reactants and products
 The law of conservation of mass must be satisfied
 If these are violated you may kill someone!!!!!
Practice
 ____CO2+___H2O yields ____C6H12O6+ ____O2
 3CO2+4H2O yields _____C3H8+_____O2
Exit Slip
 Answer these on a separate sheet of paper.
 Balance NO2 + H2O = NH3 + O2
 What should be put in the place of = in the equation
above?
 What are the three reasons we balance chemical
equations?
 What is on the left side of a chemical equation?
 What is on the right side of a chemical equation?