G10_5.2: Classifying Chemical Reactions

Classifying Chemical Reactions

Pg 157 - 166

Lesson 2

Focus Question

What are the different types of chemical
reactions?

New Vocabulary (Quizlet Practice )

synthesis reaction

combustion reaction

decomposition reaction

single-replacement reaction

double-replacement reaction

precipitate

Review Vocabulary

metal: an element that is a solid at room temperature,
is a good conductor of heat and electricity, and is
generally shiny

Multiple Choice

A molecule is________

• a glob of gelatinous goo

• smaller than an atom

• filled with raisons

• more than one atom bonded together

Multiple Choice

What is the left part of a chemical equation called?
H_{2 +} O → H₂O

• Reactants

• Products 

• Yields 

• Chemical Equation 

Multiple Choice

What is the right part of a chemical equation called?
H_{2 +} O → H₂O

• Reactants

• Products 

• Yields 

• Chemical Equation 

Multiple Choice

What are the PRODUCTS of the chemical reaction pictured?

• CH₄ and CO₂

• CH₄ and O₂

• CO₂ and H₂O

• O₂ and H₂O

Multiple Choice

CH₄ + 2 O₂ → CO₂ + 2H₂O
 In this equation, CH₄ is a

• product

• reactant

• displacement

Multiple Choice

CaCO₃ represents a chemical

• Symbol

• Formula

• Subscript

• Reaction

Multiple Choice

Which of the following models best demonstrates a balanced chemical equation?

• F

• G

• H

• J

Chemical Reactions

Evidence of a Chemical Reaction
• A temperature change can indicate a chemical

reaction. Many reactions release energy in the
form of heat and light. Other chemical
reactions absorb heat.

• Color change can indicate a chemical reaction.
• Odor, gas bubbles, and the formation of a

solid are other indications of chemical change.

Multiple Select

Which of the following are evidence of a chemical reaction? (Pick more than one.)

• Tearing paper.

• Change in color.

• Production of a gas.

• Change in temperature.

• Production of a precipitate.

Multiple Choice

A precipitate is a ___________ that forms when 2 liquids react together.

• solid

• liquid

• gas

• plasma

Multiple Choice

In a container, a solid consisting of clear crystals is combined with a blue liquid and the following observations are obtained.
 How many of the listed observations indicate a new substance was formed?

• 1

• 2

• 3

• 4

Types of Chemical Reactions

• Chemists distinguish among four chemical

reaction types: synthesis, combustion,
decomposition, and replacement reactions.

• By analyzing and comparing the reactants and

products of chemical reactions, you will begin
to notice patterns that will help you classify
them.

• Some reactions fit into more than one of the

types.

Synthesis or Combination Reactions

• In a synthesis reaction two or more substances react and combine to produce a single product.

• When two elements react, the reaction is

always a synthesis reaction.

• An example is shown below.

Multiple Choice

P₄ + 3 O₂ ----> 2 P₂O₃

• Synthesis (or combination)

• Decomposition

• Single replacement

• Double replacement

Multiple Choice

Two Reactants and One Product

• Decomposition

• Combination

• Combustion

• Single Replacement

Multiple Choice

Si + S₈ --> Si₂S₄

• Synthesis (combination)

• Decomposition

• Single replacement

• Double replacement

Combustion Reactions

• In a combustion reaction,oxygen combines

with a substance and releases energy in the
form of heat and light.

• Oxygen can combine in this way with many

substances. The following is an example.

Multiple Choice

CxHy +O₂ --> H₂O + CO₂

• Decomposition

• Double replacement

• Combustion

• Single Replacement

Multiple Choice

Always starts with a hydrocarbon that reacts with oxygen and produces carbon dioxide and water. 

• Decomposition

• Synthesis

• Combustion

• Single Replacement

Multiple Choice

What type of reaction is this?

$$2\ CO\ +\ O_2\ \rightarrow\ 2\ CO_2$$  

• Synthesis only 

• Combustion only 

• Single Displacement

• Synthesis AND combustion 

Decomposition Reactions

• In a decomposition reaction,a single compound

breaks down into two or more elements or new
compounds.

• To occur, these reactions often require an energy

source, such as heat, light, or electricity.

• The products of a decomposition reaction may

be elements, compounds, or one or more of
each.

Multiple Choice

One reactant into several products.

• Decomposition

• Synthesis

• Combustion

• Single Replacement

Multiple Choice

The following reaction is an example of what reaction type? 
CoCO₃ → CoO + CO₂

• Synthesis

• Decomposition

• Single Replacement

• Double Replacement

Multiple Choice

Pb(NO₃)₂ --> PbO + NO₂ + O₂

• Synthesis (combination)
• Decomposition
• Single replacement
• Combustion

Replacement Reactions

Single-Replacement Reactions
• In a single-replacement reaction the atoms of

one element replace the atoms of another
element in a compound.

• The following generic equation can be used to

represent single-replacement reactions.

A + BX → AX + B

Multiple Choice

One element replaces another in a compound.

• Synthesis

• Combustion

• Single Replacement

• Double Replacement

Multiple Choice

A + BC →B + AC

• Single Replacement

• Decomposition

• Double Replacement

• Synthesis

Multiple Choice

Ca + AlCl3→ CaCl_{2 +} Al

• Synthesis (combination)

• Decomposition

• Single replacement

• Double replacement

Replacement Reactions

Double-Replacement Reactions
• A double-replacement reaction occurs when

ions exchange between two compounds.

• The figure shows a generic double replacement

equation.

Multiple Choice

Switching one substance for another

• Displacement

• Synthesis

• Decomposition

• Oxidation

Multiple Choice

This pictures simulates what type of reaction?

• Synthesis

• Decomposition

• Single Replacement

• Double Replacement

Multiple Choice

KOH + H₃PO₄ --> K₃PO₄ + H₂O

• Synthesis (combination)

• Decomposition

• Single replacement

• Double replacement

Replacement Reactions

• A solid product produced during a chemical

reaction in a solution is called a precipitate.

• All double replacement reactions produce either

water, a precipitate, or a gas.

Replacement Reactions

• Reactivity is the ability to react to

another substance. An activity
series (see right) can be used to
predict reactions.

• A metal will not always replace

another metal in a compound
dissolved in water because of
different reactivities.

• Halogens frequently replace other

halogens in reactions but have
differing reactivities and do not
always replace each other.

Multiple Choice

Which of the following is more reactive?

• Calcium

• Magnesium

• Zinc

• Magnesium

Multiple Choice

Will the following reaction take place?

Ni + NaCl ->

• NO

• YES

Multiple Choice

A displacement reaction will occur when...

• a more reactive metal displaces a less reactive metal from its compound.

• A less reactive metal displaces a more reactive metal from its compound

• Displacement only occurs when two of the same metals are reacted 

• Displacement reactions will only occur in metals above iron in the reactivity series

Think of the Quiz answers before moving

to the next slide

Quiz

double-replacement

D

synthesis

C

single-replacement

B

decomposition

A

A reaction involves two substances as reactants and
produces one compound. Which type of reaction is
it likely to be?

1.

Quiz

double-replacement

D

synthesis

C

single-replacement

B

decomposition

A

A reaction involves two substances as reactants and
produces one compound. Which type of reaction is
it likely to be?

1.

CORRECT

Quiz

decomposition

D

single-replacement

C

synthesis

B

double-replacement

A

What kind of reaction does the following
generic equation represent? A + BX → AX + B

2.

Quiz

decomposition

D

single-replacement

C

synthesis

B

double-replacement

A

What kind of reaction does the following
generic equation represent? A + BX → AX + B

2.

CORRECT

Quiz

gold

D

lithium

C

sodium

B

tin

A

According to the activity series, which of the metals
is most active?

3.

Quiz

gold

D

lithium

C

sodium

B

tin

A

According to the activity series, which of the metals
is most active?

3.

CORRECT

Quiz

Subscripts are changed
to make the number of
each element equal on
both sides.

D

Coefficients are changed
to make the number of
each element equal on
both sides.

C

Coefficients are written
in their lowest possible
ratio.

B

Subscripts should never
be changed to balance
the equation.

A

Which of the following is NOTtrue about balancing
chemical equations?

4.

Quiz

Subscripts are changed
to make the number of
each element equal on
both sides.

D

Coefficients are changed
to make the number of
each element equal on
both sides.

C

Coefficients are written
in their lowest possible
ratio.

B

Subscripts should never
be changed to balance
the equation.

A

Which of the following is NOTtrue about balancing
chemical equations?

4.

CORRECT

Match

Match the following

combustion

synthesis

decomposition

single replacement

double replacement

• combustion

• synthesis

• decomposition

• single replacement

• double replacement

Match

Match the following

• 1 reactant breaks apart into 2 or more smaller products

• 2 or more reactants combine to make 1 product

• O₂ as a reactant & CO₂ and water as products

• 1 element & 1 compound in products & reactants

• 2 compounds in reactants & products

decomposition

synthesis

combustion

single replacement

double replacement

• decomposition

• synthesis

• combustion

• single replacement

• double replacement

Drag and Drop

​

Placeholder

reactions have 1 compound on both sides while ​

Placeholder

reactions have 2 compounds on both sides.​

Placeholder

reactions break apart. ​

Placeholder

reactions ​combine. ​

Placeholder

reactions must have O₂ as a reactant & CO₂ and ​H₂O as products.

Drag these tiles and drop them in the correct blank above

Single replacement

double replacement

Decomposition

Synthesis

Combustion

covalent

Covalent

Ionic

Redox

Heterogeneous

Dropdown

The reactants will be bigger than the products in a ​

Select answer

reaction. ​

Select answer

reactions have 1 element and 1 compound. The products will be bigger than the reactants in a ​

Select answer

reaction. Fuel and oxygen are needed in a ​

Select answer

reaction. ​

Select answer

reactions have 2 compounds.

Reorder

Put the equations in this order: decomposition, synthesis, combustion, single replacement, double replacement.

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5