Synthesis Reactions
Jean Brainard, Ph.D.
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Printed: August 25, 2016
AUTHOR
Jean Brainard, Ph.D.
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C HAPTER
Chapter 1. Synthesis Reactions
1
Synthesis Reactions
• Define synthesis reaction.
• Describe an example of a synthesis reaction.
In this photo of Los Angeles, California, the air over the city is brown with smog. A major component of smog is
nitrogen dioxide, which is a toxic gas with a sharp odor. Nitrogen dioxide can irritate the eyes and throat and trigger
asthma attacks. Where does this poisonous gas come from? It forms when nitric oxide—from sources such as car
exhaust—reacts with oxygen in the air. This reaction is a synthesis reaction.
What Is A Synthesis Reaction?
A synthesis reaction occurs when two or more reactants combine to form a single product. A synthesis reaction can
be represented by the general equation:
A+B→C
In this equation, the letters A and B represent the reactants that begin the reaction, and the letter C represents the
product that is synthesized in the reaction. The arrow shows the direction in which the reaction occurs.
Q: What is the chemical equation for the synthesis of nitrogen dioxide (NO2 ) from nitric oxide (NO) and oxygen
(O2 )?
A: The equation for this synthesis reaction is:
2NO + O2 → 2NO2
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Examples of Synthesis Reactions
Another example of a synthesis reaction is the combination of sodium (Na) and chlorine (Cl) to produce sodium
chloride (NaCl). This reaction is represented by the chemical equation:
2Na + Cl2 → 2NaCl
Sodium is a highly reactive metal, and chlorine is a poisonous gas. Both elements are pictured in the Figure 1.1.
The compound they synthesize has very different properties. Sodium chloride is commonly called table salt, which
is neither reactive nor poisonous. In fact, salt is a necessary component of the human diet.
FIGURE 1.1
Summary
• A synthesis reaction occurs when two or more reactants combine to form a single product. This type of
reaction is represented by the general equation: A + B → AB.
• An example of a synthesis reaction is the combination of sodium (Na) and chlorine (Cl) to produce sodium
chloride (NaCl). This reaction is represented by the chemical equation: 2Na + Cl2 → 2NaCl.
Explore More
Watch the two-video sequence on synthesis reactions, and then answer the questions below.
MEDIA
Click image to the left or use the URL below.
URL: https://www.ck12.org/flx/render/embeddedobject/82349
MEDIA
Click image to the left or use the URL below.
URL: https://www.ck12.org/flx/render/embeddedobject/82350
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1.
2.
3.
4.
Chapter 1. Synthesis Reactions
Why is it easy to identify synthesis reactions?
What is the product of the synthesis reaction in which sodium combines with oxygen?
Write a balanced chemical equation for the synthesis reaction in which nitrogen reacts with hydrogen.
Complete the following two synthesis reactions by filling in the missing products:
a. 2Al + 3Br2 → ?
b. 2K + S → ?
Review
1. What is a synthesis reaction?
2. Describe the synthesis reaction that produces table salt.
3. Which of the following is a synthesis reaction?
a.
b.
c.
d.
2H2 O → 2H2 + O2
2NO + O2 → 2NO2
2K + 2H2 O → 2KOH + H2
CH4 + 2O2 → CO2 + 2H2 O
Resources
MEDIA
Click image to the left or use the URL below.
URL: https://www.ck12.org/flx/render/embeddedobject/177399
References
1. Sodium: User:Jurii/Wikimedia Commons; Chlorine: User:Greenhorn1/Wikimedia Commons; Salt: Dubravko
Sorić. Sodium and chlorine combine to form sodium chloride, table salt . Sodium: CC BY 3.0; Chlorine:
Public Domain; Salt: CC BY 2.0
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