Chemistry Ch 11.1
Describing Chemical Reactions
• Big Idea: Reactions
• Big Questions:
• 1. How do chemical reactions obey
the law of conservation of mass?
• 2. How can you predict the products
of a chemical reaction?
Objectives:
• Describe how to write a word equation.
• Descri e how to write a skeleton
equation.
• Balance chemical reactions using the
law of conservation of mass.
• Describe the steps for writing a
balanced chemical equation.
Vocabulary:
• chemical equation
• skeleton equation
• catalyst
• coefficients
• balanced equation
• (Law of Conservation of Mass)
Key to Presentation
• Letters on “slides” are for questions to
answer after reading and discussion of
section 11.1
• Numbers on “slides” refer to problems
on Section Assessment on pg 329
• Practice Problems should be answered
on the output page in notebook.
A. How do you write a word equation?
B. How do you write a skeleton
equation?
C. What is a catalyst and how do you
include it in an equation?
Practice Problems: Writing a Skeleton
Equation, pg 324
• 1. Write a sentence that describes this
chemical reaction.
• Na(s) + H2O(l)
NaOH(aq) + H2(g)
Practice Problems: Writing a Skeleton
Equation, pg 324
• 2. Sulfur burns in oxygen to form sulfur
dioxide. Write a skeleton equation for
this chemical reaction. Include
appropriate symbols from Table 11.1
10. Write skeleton equations for these
reactions
• a. Heating copper(II) sulfide in the presence
of diatomic oxygen produces pure copper
and sulfur dioxide gas.
• Cu+ O2
Cu + SO2
• b. When heated, baking soda (sodium
hydrogen carbonate) decomposes to form
the products sodium carbonate, carbon
dioxide, and water.
• NaHCO3
Na2CO3 + CO2 + H2O
D. Describe the steps in writing a
balanced chemical equation.
E. What are coefficients?
F. What is a balanced equation?
G. What is the law of conservation of
mass?
Practice Problems: Writing a Balanced
Chemical Eqution
• Balance each equation:
• a. 2AgNO3 + H2S
Ag2S + 2HNO3
• b. 3Zn(OH)2 + 2H3PO4
6H2O
Zn3(PO4)2 +
11. Write and balance equations for the
following reactions
• a. Iron metal and chlorine gas react to form solid
iron(III) chloride.
• 2Fe(s) + 3Cl2(g)
2FeCl3(s)
• b. Solid aluminum carbonate decomposes to form
solid aluminum oxide and carbon dioxide gas.
• Al2(CO3)3(s)
Al2O3(s) + 3CO2(g)
• c. Solid magnesium reacts with aqueous silver
nitrate to form solid silver and aqueous magnesium
nitrate.
• Mg(s) + 2AgNO3(aq)
2Ag(s) + Mg(NO3)2(aq)
12. Balance the following equations.
• a. SO2 + O2
SO3
12. Balance the following equations.
• b. Fe2O3 + 3 H2
2 Fe + 3 H2O
12. Balance the following equations.
• c. 4 P + 5 O2
P4O10
12. Balance the following equations.
• d. 2 Al + N2
2 AlN