The 5 Types of Chemical Reactions

Also known as – Combination reaction

It is a chemical change in which two or more substances react to forma new singular substance.

The product is a compound in this form of reaction.

You can tell this reaction has occurred because on the reactant side there are multiple substances, while on the product side there is only one product.

1. Synthesis Reactions

Synthesis Reaction

A + B AB

When a single compound (the reactant) breaks down into two or more simpler products.

This type of reaction can be identified by:

It is the exact opposite of a synthesis reaction; if you know one you know them both.

There is always one reactant. If you see one reactant that’s a compound and several products, a decomposition reaction has occurred.

2. Decomposition Reactions

Decomposition Reaction

AB A+B

A chemical change where one element replaces a second element in compound

This reaction is identifiable by its symmetry. On the reactant side there is a single element and a compound, as there is on the product side

No reaction will occur if the most reactive element is already in the compound

3. Single Replacement Reactions

Single Replacement Reaction

A + BC AC + B

A chemical change where there is an exchange of positive ions between two compounds

May also be called double-displacement reactions

Generally occurs in aqueous solution

Often produces a precipitate,a gas, or a molecular compound, water for example.

4. Double Replacement Reactions

AB + CD AD + BC

Double Replacement Reactions

A chemical change where an element or a compound reacts with oxygen.

This will often yield energy in the form of heat and light.

Oxygen is ALWAYS going to be on the reactant side of the equation. This is the main indicator that a combustion reaction has occurred.

5. Combustion Reactions

Combustion Reaction

CH4 + O2 CO2 + H2O + energyMethane

Carbon Dioxide

Oxygen Water

CH4 + 2O2 CO2 + 2H2O + energy

Balanced combustion reaction

Practice Problems

What type of reaction is this?

AgNO3(aq) + KCl(aq) AgCl(s) + KNO3(aq)

Practice Problems

What type of reaction is this?

AgNO3(aq) + KCl(aq) AgCl(s) + KNO3(aq)

This is a Double-Replacement reaction. You can tell this because there are two compounds on each side of the equation and each compound swapped the latter of the 2 elements.

What type of reaction is this?

Br2(l) + 2NaI(s) 2NaBr(s) + I2(s)

This is a Single-Replacement reaction. You can tell this because there is a single element on the reactant side Br2(l). Br2(l) becomes part of the compound on the product side 2Nabr(s).

Practice Problems

Practice Problems

Fill in the blank:

CH4 + ___ CO2 + H2O

Fill in the blank:

CH4 + ___ CO2 + H2O

The answer is O2 because this is a Combustion reaction. You can identify this as a combustion reaction because:

Oxygen is on the product side, which means it is most likely on the reactant side as well.

Carbon dioxide was formed, a common product in combustion reactions.

Practice Problems

What type of reaction is this?

Br2(aq) + NaCl(aq)

Practice Problems

What type of reaction is this?

Br2(aq) + NaCl(aq)

This is a trick question! There will be no reaction because Bromine is less reactive than Chlorine. Remember, if the most reactive element is already in the compound, there will be NO chemical reaction.

Practice Problems

Quiz Yourself

Answer the following question with either: Always, Frequently, or Never

1. In a combustion reaction, oxygen is ________ on the reactant side.

2. In a synthesis reaction, there are ________ two or more products.

3. A decomposition reaction ________ requires energy in the form of heat, light, or electricity.

Quiz Yourself

Answer the following question with either: Always, Frequently, or Never

1. In a combustion reaction, oxygen is ALWAYS on the reactant side.

2. In a synthesis reaction, there are NEVER two or more products.

3. A decomposition reaction FREQUENTLY requires energy in the form of heat, light, or electricity.