I can write a chemical
equation to describe a
chemical reaction.
reaction.
Warm Up 12/6
What is a chemical change?
Chemical Reactions
List at least 3 signs that chemical change may
be occurring.
Burning Magnesium
Chemical Equations
Chemical Equation
1. List 5 observations about the magnesium before
the reaction.
What substances did we have before the
reaction?
2. What is the mass of the crucible and magnesium
before the reaction?
Magnesium(Mg) and oxygen(O2)
3. List your observations during the reaction.
What substance did the reaction produce?
4. List 5 observations after the reaction.
Magnesium oxide (MgO)
5. What is the mass of the crucible and its contents
after the reaction?
Chemical Equation
Chemical Equation
Mg + O2 → MgO
Mg + O2 → MgO
“magnesium and oxygen react to produce
magnesium oxide”
Mg + O2 are the reactants, substances going in
to the reaction.
MgO is the product, substance coming out of the
reaction.
Chemical Equation
Chemical Equation
Did our equation show conservation of mass?
The Law of Conservation of Mass – mass is not
created or destroyed in chemical reactions.
Mg + O2 → MgO
No,
24 amu + 32 amu → 24 amu + 16 amu
56 amu ≠ 40 amu
Chemical Equation
We can use coefficients to make our equation
show conservation of mass.
A chemical equation that shows conservation of
mass is called a balanced equation.
2Mg + O2 → 2MgO
“Two atoms of magnesium react with one
molecule of oxygen to produce two units of
magnesium oxide.”