Synthesis: Two or more
substances combine to make a
single substance.
Two or more substances combine
to make a single substance.
Decomposition: a substance breaks
down into two or more substances
Decomposition: forms Calcium
oxide and carbon dioxide
Single Displacement: One
substance takes the place of
another.
Single displacement: Iron takes the
place of Copper here
Double Displacement: The
compounds ‘switch partners’
Mid-switch:
Final products:
Combustion: a substance rapidly
combines with oxygen.
Forms oxides and releases
energy!
11.1
Describing Chemical Reactions
On May 6, 1937, the huge airship
Hindenburg erupted into a fireball.
Within a short time, 210,000 cubic
meters of hydrogen had burned and
the airship was destroyed. The
chemical reaction that occurred is
“hydrogen combines with oxygen to
produce water.” You will learn to
represent this chemical reaction by a
chemical equation.
[What is a chemical reaction?]
A.
B.
C.
D.
[Option 1]
[Option 2]
[Option 3]
[Option 4]
11.1
Writing Chemical Equations
Writing Chemical Equations
How do you write a word equation?
11.1
Writing Chemical Equations
Word Equations
To write a word equation, write the
names of the reactants to the left of the
arrow separated by plus signs; write the
names of the products to the right of the
arrow, also separated by plus signs.
Reactant + Reactant  Product + Product
11.1
Writing Chemical Equations
Methane + Oxygen  Carbon dioxide + Water
11.1
Writing Chemical Equations
iron + oxygen
iron(III) oxide
11.1
Writing Chemical Equations
Hydrogen Peroxide  Water and Oxygen
11.1
Writing Chemical Equations
Chemical Equations
A chemical equation is a representation of a
chemical reaction; the formulas of the
reactants (on the left) are connected by
an arrow with the formulas of the products
(on the right).
11.1
Writing Chemical Equations
How do you write a skeleton equation?
11.1
Writing Chemical Equations
Write the formulas of the reactants to
the left of the yields sign (arrow) and
the formulas of the products to the
right.
11.1
Writing Chemical Equations
A skeleton equation is a chemical equation
that does not indicate the relative amounts
of the reactants and products.
Here is the equation for rusting:
Fe + O2  Fe2O3
11.1
Writing Chemical Equations
A catalyst is a substance that speeds up the
reaction but is not used up in the reaction.
Without Catalyst
With Catalyst
11.1
Writing Chemical Equations
for Conceptual Problem 11.1
Problem Solving 11.2 Solve Problem
2 with the help of an interactive guided
tutorial.
11.1
Balancing Chemical Equations
Balancing Chemical Equations
What are the steps in writing a balanced
chemical equation?
11.1
Balancing Chemical Equations
To write a balanced chemical equation,
first write the skeleton equation. Then
use coefficients to balance the equation
so that it obeys the law of conservation
of mass.
11.1
Balancing Chemical
Equations
This is a balanced equation for making a
bicycle. The numbers are called
coefficients—small whole numbers that
are placed in front of the formulas in an
equation in order to balance it.
11.1
Balancing Chemical
Equations
A chemical reaction is also described by a
balanced equation in which each side of the
equation has the same number of atoms of
each element and mass is conserved.
Balancing Chemical Equations
Simulation 11
Sharpen your skills by balancing chemical
equations.
for Conceptual Problem 11.2
Problem Solving 11.4 Solve Problem
4 with the help of an interactive guided
tutorial.
for Conceptual Problem 11.2
Problem Solving 11.6 Solve Problem
6 with the help of an interactive guided
tutorial.
11.1 Section Quiz.
1. Propane gas reacts with oxygen to produce
water vapor and carbon dioxide. Choose the
correct word equation for this reaction.
a. propane + carbon dioxide
oxygen
water +
b. propane + oxygen + water
dioxide
carbon
c. propane + oxygen + water + carbon
dioxide
d. propane + oxygen
dioxide
water + carbon
11.1 Section Quiz.
2. Which of the following is a skeleton equation?
a. H2 + CO
b. 2H2 + CO
c. 2H2 + CO2
CH3OH
CH3OH
CH3OH
d. hydrogen + carbon monoxide
methanol
11.1 Section Quiz.
3. What coefficient for H2SO4 is required to
balance the following equation?
Ca3(PO4)2 + ____ H2SO4
a. 1
b. 2
c. 3
d. 4
3CaSO4 + 2H3PO4
END OF SHOW