Science: Types of Chemical Reactions Worksheet

Question 1

A reaction combines iron and sulfur to make iron sulfide: Fe + S -> FeS. What type of chemical reaction is this?

Accepted Answer

This is a synthesis reaction because two simpler substances combine to form one compound, iron sulfide.

Question 2

Calcium carbonate breaks down when heated: CaCO3 -> CaO + CO2. What type of chemical reaction is this?

Accepted Answer

This is a decomposition reaction because one compound breaks apart into two simpler substances.

Question 3

Zinc reacts with hydrochloric acid: Zn + 2HCl -> ZnCl2 + H2. What type of chemical reaction is this?

Accepted Answer

This is a single replacement reaction because zinc replaces hydrogen in hydrochloric acid and forms zinc chloride and hydrogen gas.

Question 4

Silver nitrate reacts with sodium chloride: AgNO3 + NaCl -> AgCl + NaNO3. What type of chemical reaction is this?

Accepted Answer

This is a double replacement reaction because the ions in the two compounds switch partners and form two new compounds.

Question 5

Methane burns in oxygen: CH4 + 2O2 -> CO2 + 2H2O. What type of chemical reaction is this?

Accepted Answer

This is a combustion reaction because a fuel reacts with oxygen and produces carbon dioxide and water.

Question 6

Describe what makes a synthesis reaction different from a decomposition reaction.

Accepted Answer

A synthesis reaction builds a larger compound from simpler substances, while a decomposition reaction breaks one compound into simpler substances.

Question 7

In the reaction Cl2 + 2KBr -> 2KCl + Br2, what type of reaction occurs, and which element is replaced?

Accepted Answer

This is a single replacement reaction, and chlorine replaces bromine in potassium bromide.

Question 8

In the reaction BaCl2 + Na2SO4 -> BaSO4 + 2NaCl, what type of reaction occurs?

Accepted Answer

This is a double replacement reaction because barium and sodium exchange partners with chloride and sulfate.

Question 9

Hydrogen peroxide breaks down into water and oxygen: 2H2O2 -> 2H2O + O2. What type of reaction is this?

Accepted Answer

This is a decomposition reaction because hydrogen peroxide breaks into water and oxygen gas.

Question 10

Magnesium burns in oxygen to form magnesium oxide: 2Mg + O2 -> 2MgO. Name the reaction type and explain your choice.

Accepted Answer

This is a synthesis reaction because magnesium and oxygen combine to make one product, magnesium oxide.

Question 11

A student says that every reaction with oxygen is combustion. Is that statement always correct? Explain.

Accepted Answer

That statement is not always correct. Some reactions involve oxygen but are classified in other ways, such as synthesis, if substances simply combine to form one product.

Question 12

Classify this reaction: 2KClO3 -> 2KCl + 3O2. Then explain what happens to the reactant.

Accepted Answer

This is a decomposition reaction. The compound potassium chlorate breaks apart into potassium chloride and oxygen gas.

Science: Types of Chemical Reactions

Science: Types of Chemical Reactions

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