Chemical Reactions
Chapter 11
Do Now- In your own words
Write an explanation for what
Is happening in this picture.
Objective- 11.1 Describing Chemical Reactions
HW – Pg 329 # 9-12
11.1 Describing Chemical Reactions
• Word Equations
11.1 Describing Chemical Reactions
• Word Equations
Reactants → Products
11.1 Describing Chemical Reactions
• Word Equations
Reactants → Products
iron + oxygen → iron(III) oxide
Symbols Used in Chemical Reactions
+
→
↔
(s)
(l)
(g)
(aq)
Heat
Pt
∆
Symbols Used in Chemical Reactions
+
→
↔
(s)
(l)
(g)
(aq)
Heat
Pt
Separates two reactant and two products
“Yields” Separates reactants from products
Reaction is reversible
solid
liquid
gas
aqueous solution
∆ heat was supplied to reaction
Element (Pt) used as catalyst
• Chemical Equations
Reactants → Products
iron + oxygen → iron(III) oxide
Fe + O2 → Fe2O3
+
+
+
→
• Chemical Equations
Reactants → Products
iron + oxygen → iron(III) oxide
Fe + O2 → Fe2O3
4Fe(s) + 3O2(g) → 2Fe2O3 (s)
Magnesium + Oxygen → Magnesium oxide
Magnesium + Oxygen → Magnesium oxide
Mg + O2 → MgO
Magnesium + Oxygen → Magnesium oxide
Mg + O2 → MgO
2Mg + O2 → 2MgO
• Do Now - Write the ionic or molecular formula
for Lithium Oxide
Aluminum Sulfide
Silicon Oxide
• Objective – Balance Chemical Equations
• Homework – finish Pg. 329 # 9 – 12 and
handout
• Do Now - Write the ionic or molecular formula
for Lithium Oxide Li2O
Aluminum Sulfide Al2S3
Silicon Oxide
SiO2
Balancing Chemical Equations
Take the time to write the steps you used to
balance this problem. If you can write the steps
used you can use them to balance any chemical
equation.
Fe
+
O2
→ Fe2O3
1. Determine correct formulas for all
reactants and products.
2. Write a skeleton equation.
3. Determine the number of atoms of
each element on the reactant side
and the product side.
4. Balance the number of atoms of
each element by adding coefficients.
(The subscripts can’t be changed
now)
5. Check that the number of atoms of
each element is the same on both
sides.
6. Check to see that all coefficients
are in lowest whole number ratio
possible.
Iron +
Fe
+
oxygen → iron oxide
O2
→ Fe2O3
1. Determine correct formulas for all
reactants and products.
2. Write a skeleton equation.
3. Determine the number of atoms of
each element on the reactant side
and the product side.
4. Balance the number of atoms of
each element by adding coefficients.
(The subscripts can’t be changed
now)
5. Check that the number of atoms of
each element is the same on both
sides.
6. Check to see that all coefficients
are in lowest whole number ratio
possible.
Iron +
Fe
Fe
O
+
oxygen → iron oxide
O2
→ Fe2O3
Fe
O
1. Determine correct formulas for all
reactants and products.
2. Write a skeleton equation.
3. Determine the number of atoms of
each element on the reactant side
and the product side.
4. Balance the number of atoms of
each element by adding coefficients.
(The subscripts can’t be changed
now)
5. Check that the number of atoms of
each element is the same on both
sides.
6. Check to see that all coefficients
are in lowest whole number ratio
possible.
Iron +
Fe
Fe 1
O 2
+
oxygen → iron oxide
O2
→ Fe2O3
Fe 2
O 3
1. Determine correct formulas for all
reactants and products.
2. Write a skeleton equation.
3. Determine the number of atoms of
each element on the reactant side
and the product side.
4. Balance the number of atoms of
each element by adding coefficients.
(The subscripts can’t be changed
now)
5. Check that the number of atoms of
each element is the same on both
sides.
6. Check to see that all coefficients
are in lowest whole number ratio
possible.
Iron +
Fe
+
oxygen → iron oxide
O2
Fe 1
O 2
Fe
Fe 1
O 2
→ Fe2O3
Fe 2
O 3
+
O2
→ Fe2O3
Fe 2
O 3
1. Determine correct formulas for all
reactants and products.
2. Write a skeleton equation.
3. Determine the number of atoms of
each element on the reactant side
and the product side.
Iron +
Fe
+
oxygen → iron oxide
O2
Fe 1
O 2
4. Balance the number of atoms of
each element by adding coefficients.
(The subscripts can’t be changed
now)
Fe
5. Check that the number of atoms of
each element is the same on both
sides.
6. Check to see that all coefficients
are in lowest whole number ratio
possible.
Fe
Fe 2
O 3
+
O2
Fe 1
O 2
Fe
O
→ Fe2O3
→ Fe2O3
Fe 2
O 3
+
O2
→ Fe2O3
Fe
O
1. Determine correct formulas for all
reactants and products.
2. Write a skeleton equation.
3. Determine the number of atoms of
each element on the reactant side
and the product side.
Iron +
Fe
oxygen → iron oxide
+
O2
Fe 1
O 2
4. Balance the number of atoms of
each element by adding coefficients.
(The subscripts can’t be changed
now)
Fe
5. Check that the number of atoms of
each element is the same on both
sides.
6. Check to see that all coefficients
are in lowest whole number ratio
possible.
4Fe
Fe 2
O 3
+
O2
Fe 1
O 2
Fe 4
O 6
→ Fe2O3
→ Fe2O3
Fe 2
O 3
+
3O2
→ 2Fe2O3
Fe 4
O 6
1. Determine correct formulas for all
reactants and products.
2. Write a skeleton equation.
3. Determine the number of atoms of
each element on the reactant side
and the product side.
Iron +
Fe
oxygen → iron oxide
+
O2
Fe 1
O 2
4. Balance the number of atoms of
each element by adding coefficients.
(The subscripts can’t be changed
now)
Fe
5. Check that the number of atoms of
each element is the same on both
sides.
6. Check to see that all coefficients
are in lowest whole number ratio
possible.
4Fe
Fe 2
O 3
+
O2
Fe 1
O 2
→ Fe2O3
Fe 2
O 3
+
3O2
Fe 4
O 6
4Fe
→ Fe2O3
→ 2Fe2O3
Fe 4
O 6
+
3O2
→ 2Fe2O3