Chemical Reactions: Interactive Quizzes and Learning Materials

Question 1

What type of chemical reaction occurs when a compound breaks down into simpler substances?

Accepted Answer

Decomposition

Answer

Combustion

Answer

Synthesis

Answer

Neutralisation

Question 2

What is the difference between an exothermic and endothermic reaction?

Accepted Answer

Exothermic reactions release heat, while endothermic reactions absorb heat.

Answer

Endothermic reactions release heat, while exothermic reactions absorb heat.

Answer

Exothermic reactions occur faster than endothermic reactions.

Answer

Endothermic reactions occur faster than exothermic reactions.

Question 3

What is the role of oxygen in combustion reactions?

Accepted Answer

It is a reactant that combines with the fuel to produce heat and light.

Answer

It is a product that is released when the fuel burns.

Answer

It is a catalyst that speeds up the reaction.

Answer

It is an inhibitor that slows down the reaction.

Question 4

What is the primary purpose of a Bunsen burner in a laboratory setting?

Accepted Answer

To produce a concentrated flame for heating experiments

Answer

To evenly heat liquids and solids

Answer

To provide lighting

Answer

To measure temperature

Question 5

True or False: In a decomposition reaction, a single substance breaks down into two or more simpler substances.

Accepted Answer

True

Answer

False

Question 6

The chemical symbol for potassium is:

Accepted Answer

K

Answer

Po

Answer

Pt

Answer

Pu

Question 7

The symbol equation for the reaction between hydrogen and chlorine to form hydrogen chloride is:

Accepted Answer

2H + Cl2 -> 2HCl

Answer

H + Cl -> HCl

Answer

2H + Cl -> 2HCl

Answer

H + Cl2 -> HCl

Question 8

What is the word for a chemical reaction in which two or more substances combine to form only one product?

Accepted Answer

Synthesis

Answer

Combustion

Answer

Decomposition

Answer

Displacement

Question 9

Which one of these is a balanced chemical equation?

Accepted Answer

2H2 + O2 → 2H2O

Answer

H2 + O2 → H2O

Answer

2H + O → H2O

Answer

H2O → H2 + O2

Question 10

What are the products of the combustion of methane?

Accepted Answer

Water and carbon dioxide

Answer

Carbon monoxide and hydrogen

Answer

Carbon dioxide and hydrogen

Answer

Water and carbon monoxide

Question 11

Which one of the following is a decomposition reaction?

Accepted Answer

CaCO3 → CaO + CO2

Answer

2Na + 2H2O → 2NaOH + H2

Answer

CH4 + 2O2 → CO2 + 2H2O

Answer

Fe + CuSO4 → FeSO4 + Cu

Question 12

What is the reason for balancing chemical equations?

Accepted Answer

To make sure that the number of atoms of each element is the same on both sides of the equation

Answer

To make the equations easier to read

Answer

To predict the products of a reaction

Answer

To calculate the rate of a reaction

Question 13

What is the chemical formula for common salt?

Accepted Answer

NaCl

Answer

Na2Cl

Answer

ClNa

Answer

NaCl2

Question 14

What is the main difference between a chemical reaction and a physical change?

Accepted Answer

A chemical reaction involves a change in the chemical composition of a substance, while a physical change does not.

Answer

A physical change involves a change in the chemical composition of a substance, while a chemical reaction does not.

Answer

Chemical reactions are always irreversible, while physical changes are always reversible.

Answer

Physical changes are always irreversible, while chemical reactions are always reversible.

Question 15

Which of these is NOT a chemical reaction?

Accepted Answer

Freezing

Answer

Combustion

Answer

Decomposition

Question 16

Which of the below is NOT a type of chemical reaction?

Accepted Answer

Evaporation

Answer

Combustion

Answer

Decomposition

Answer

Synthesis

Question 17

When methane burns in air, what type of reaction does it represent?

Accepted Answer

Combustion

Answer

Decomposition

Answer

Synthesis

Question 18

What is the balanced chemical equation for the decomposition of water?

Accepted Answer

2H2O → 2H2 + O2

Answer

H2O → H + O

Answer

3H2O → 3H2 + O3

Answer

4H2O → 4H2 + 2O2

Question 19

Which of the following is a chemical change?

Accepted Answer

Burning wood

Answer

Melting ice

Answer

Dissolving salt in water

Question 20

What results from the synthesis reaction between hydrogen and oxygen?

Accepted Answer

Water

Answer

Hydrogen peroxide

Answer

Ozone

Question 21

Which of the following is NOT a type of chemical reaction?

Accepted Answer

Evaporation

Answer

Combustion

Answer

Decomposition

Answer

Synthesis

Question 22

What do we call a reaction where two or more substances combine to form a single new substance?

Accepted Answer

Synthesis

Answer

Combustion

Answer

Decomposition

Answer

Neutralization

Question 23

Which of the following is NOT a product of combustion reactions?

Accepted Answer

Nitrogen

Answer

Carbon dioxide

Answer

Water

Answer

Ash

Question 24

What is the balanced chemical equation for the combustion of methane?

Accepted Answer

CH₄ + 2O₂ → CO₂ + 2H₂O

Answer

CH₄ + O₂ → CO + 2H₂O

Answer

2CH₄ + O₂ → CO₂ + 2H₂O

Answer

CH₄ + 3O₂ → CO₂ + 2H₂O

Question 25

What happens to the mass of the reactants and products in a chemical reaction?

Accepted Answer

The total mass of the reactants is equal to the total mass of the products.

Answer

The total mass of the reactants is greater than the total mass of the products.

Answer

The total mass of the products is greater than the total mass of the reactants.

Answer

The total mass of the reactants and products is always changing.

Question 26

What do catalysts do in a chemical reaction?

Accepted Answer

Speed up the reaction

Answer

Slow down the reaction

Answer

Stop the reaction

Answer

Reverse the reaction

Question 27

Which of the following does NOT affect the rate of a chemical reaction?

Accepted Answer

Color of the reactants

Answer

Temperature

Answer

Concentration of reactants

Answer

Presence of a catalyst

Question 28

What is the main difference between a chemical reaction and a physical change?

Accepted Answer

Chemical reactions create new substances, while physical changes do not.

Answer

Physical changes create new substances, while chemical reactions do not.

Answer

Both chemical reactions and physical changes create new substances.

Answer

Neither chemical reactions nor physical changes create new substances.

Question 29

Which of the following is an example of an exothermic reaction?

Accepted Answer

Burning of gasoline

Answer

Dissolving salt in water

Answer

Melting of ice

Answer

Photosynthesis

Question 30

In a chemical reaction, what happens to the combined mass of the starting materials compared to the mass of the final products?

Accepted Answer

The combined mass of the starting materials is equal to the mass of the final products.

Answer

The combined mass of the starting materials is less than the mass of the final products.

Answer

The combined mass of the starting materials is greater than the mass of the final products.

Question 31

Which of the following is NOT a type of chemical change?

Accepted Answer

Physical change

Answer

Decomposition

Answer

Combustion

Answer

Synthesis

Question 32

In a combustion reaction, what is the substance that reacts with oxygen to produce energy?

Accepted Answer

Fuel

Answer

Reactant

Answer

Product

Answer

Catalyst

Question 33

Which of the following is the correct word equation for the decomposition of water?

Accepted Answer

Water -> Hydrogen + Oxygen

Answer

Hydrogen + Oxygen -> Water

Answer

Oxygen -> Water + Hydrogen

Answer

Water + Hydrogen -> Oxygen

Question 34

Which of the following is a balanced chemical equation?

Accepted Answer

2H2 + O2 -> 2H2O

Answer

H2 + O -> H2O

Answer

2H2 + 2O2 -> H2O

Question 35

What is the main purpose of balancing chemical equations?

Accepted Answer

To ensure that the number of atoms of each element is the same on both sides of the equation.

Answer

To predict the products of the reaction

Answer

To make them easier to solve

Answer

To determine the rate of the reaction

Question 36

Which of the following is an example of an exothermic reaction?

Accepted Answer

Burning of methane

Answer

Melting of ice

Answer

Dissolving of salt in water

Answer

Condensation of water vapor

Question 37

What is the difference between a reactant and a product in a chemical reaction?

Accepted Answer

Reactants are the starting substances, while products are the ending substances

Answer

Products are always more complex than reactants

Answer

Reactants are always gases, while products are always solids

Question 38

What is the role of a catalyst in a chemical reaction?

Accepted Answer

To speed up the reaction without being consumed

Answer

To change the products of the reaction

Answer

To slow down the reaction

Answer

To create new reactants

Question 39

Which of the following is a chemical change?

Accepted Answer

Burning of wood

Answer

Dissolving of salt in water

Answer

Melting of ice

Answer

Boiling of water

Question 40

What type of reaction is represented by the following equation: 2H2 + O2 -> 2H2O?

Accepted Answer

Synthesis

Answer

Combustion

Answer

Single-replacement

Answer

Decomposition

Question 41

What is the product of the following decomposition reaction: CaCO3 -> CaO + CO2?

Accepted Answer

Calcium oxide and carbon dioxide

Answer

Calcium carbonate and carbon monoxide

Answer

Calcium hydroxide and carbon dioxide

Answer

Calcium oxide and carbon monoxide

Question 42

Which of the following is a balanced chemical equation?

Accepted Answer

2Fe + 3O2 -> Fe2O3

Answer

Fe + 2O -> FeO2

Answer

Fe + O -> FeO2

Answer

Fe2 + O2 -> FeO

Question 43

What is the mole ratio of hydrogen to oxygen in the balanced equation: 2H2 + O2 -> 2H2O?

Accepted Answer

4 : 1

Answer

1 : 2

Answer

1 : 4

Answer

2 : 1

Question 44

Which of the following is a combustion reaction?

Accepted Answer

Methane burning in air

Answer

Sodium reacting with water

Answer

Hydrochloric acid reacting with sodium hydroxide

Answer

Iron rusting

Question 45

What is the catalyst in the following reaction: 2H2O2 -> 2H2O + O2?

Accepted Answer

None

Answer

Water

Answer

Oxygen

Answer

Hydrogen peroxide

Question 46

What is the activation energy of a chemical reaction?

Accepted Answer

The minimum amount of energy required for the reaction to occur

Answer

The energy of the products

Answer

The amount of energy released by the reaction