Chemical Reactions: Interactive Quizzes and Learning Materials

Question 1

What is a distinguishing characteristic of an exothermic reaction?

Accepted Answer

Release of heat into the surroundings

Answer

Absorption of heat from the surroundings

Answer

Decrease in the temperature of the surroundings

Answer

Products have more energy than reactants

Question 2

What is the oxidation number of sulfur in sulfuric acid (H2SO4)?

Accepted Answer

+6

Answer

+2

Answer

+4

Answer

-2

Question 3

Calculate the molar mass of sulfuric acid (H2SO4).

Accepted Answer

98 g/mol

Answer

32 g/mol

Answer

49 g/mol

Answer

64 g/mol

Question 4

Which of the following is an example of a qualitative observation?

Accepted Answer

The solution turned blue.

Answer

The temperature increased.

Answer

The mass of the reactants decreased.

Answer

The volume of the gas produced was 100 mL.

Question 5

What is the primary purpose of using a reflux condenser in a chemical reaction setup?

Accepted Answer

To prevent the loss of volatile liquids

Answer

To increase the reaction rate

Answer

To lower the boiling point of the reaction mixture

Answer

To purify the products

Question 6

When sodium reacts with chlorine, the products formed are:

Accepted Answer

Sodium chloride

Answer

Sodium chloride and hydrogen

Answer

Sodium oxide and chlorine gas

Answer

Sodium hydroxide and chlorine gas

Question 7

In a reaction between an acid and a base, the products formed are:

Accepted Answer

Salt and water

Answer

Salt and hydrogen

Answer

Acid and hydroxide

Answer

Base and water

Question 8

The chemical equation for the complete combustion of methane is:

Accepted Answer

CH4 + 2O2 → CO2 + 2H2O

Answer

CH4 + O2 → CO + 2H2

Answer

CH4 + 2O2 → C + 2H2O

Answer

CH4 + O2 → CO2 + H2

Question 9

Which of the following is a catalyst, a substance that increases the rate of a reaction without being consumed?

Accepted Answer

Platinum

Answer

Sodium chloride

Answer

Water

Answer

Carbon dioxide

Question 10

The activation energy of a reaction is:

Accepted Answer

The minimum energy required to initiate a reaction

Answer

The maximum energy released during a reaction

Answer

The energy difference between reactants and products

Answer

The energy required to break chemical bonds

Question 11

Which intermolecular force contributes most to water's high boiling point?

Accepted Answer

Hydrogen bond

Answer

Ionic bond

Answer

Covalent bond

Answer

Van der Waals force

Question 12

How does chromatography separate different substances in a mixture?

Accepted Answer

By their different solubilities.

Answer

By their different particle sizes.

Answer

By their different boiling points.

Answer

Chromatography doesn't separate mixtures.

Question 13

What is the term for when atoms or molecules rearrange to form new substances?

Accepted Answer

Chemical reaction

Answer

Chemical bonding

Answer

Physical change

Answer

Nuclear reaction

Question 14

In an endothermic reaction, what happens to the energy?

Accepted Answer

Energy is absorbed

Answer

Energy is released

Answer

Energy remains constant

Answer

Energy is converted to heat

Question 15

What is the definition of a catalyst?

Accepted Answer

Substance that speeds up reactions without being consumed

Answer

Reactant

Answer

Product

Answer

Substance that slows down reactions

Question 16

Select an example of a neutralization reaction.

Accepted Answer

Reaction of an acid and a base

Answer

Burning of methane

Answer

Rusting of iron

Answer

Photosynthesis

Question 17

Which law states that the total mass of reactants in a chemical reaction is equal to the total mass of products?

Accepted Answer

Law of Conservation of Matter

Answer

Law of Conservation of Energy

Answer

Law of Definite Proportions

Answer

Law of Multiple Proportions

Question 18

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

Accepted Answer

Fermentation

Answer

Combination

Answer

Displacement

Answer

Decomposition

Question 19

In the equation 2H2 + O2 → 2H2O, what is the coefficient in front of oxygen?

Accepted Answer

2

Answer

1

Answer

4

Answer

8

Question 20

Which of the following reactions is exothermic?

Accepted Answer

Burning of wood

Answer

Melting of ice

Answer

Dissolving salt in water

Answer

Evaporation of water

Question 21

What is the oxidation number of chlorine in HCl?

Accepted Answer

-1

Answer

0

Answer

+1

Answer

+2

Question 22

Which of the following is a strong acid?

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Carbonic acid

Answer

Phosphoric acid

Question 23

What is the pH of a neutral solution?

Accepted Answer

7

Answer

0

Answer

14

Answer

28

Question 24

Which of the following can be used to neutralize an acid?

Accepted Answer

Base

Answer

Salt

Answer

Metal

Answer

Non-metal

Question 25

What is the molar mass of sodium chloride (NaCl)?

Accepted Answer

58.5 g/mol

Answer

23 g/mol

Answer

35.5 g/mol

Answer

71 g/mol

Question 26

What is the balanced equation for the reaction between sodium and chlorine gas?

Accepted Answer

2Na + Cl₂ → 2NaCl

Answer

Na + Cl → NaCl

Answer

NaCl + Na → Cl₂

Answer

2NaCl + Na → 2Cl

Question 27

Which of the following is an exothermic reaction?

Accepted Answer

Burning of methane

Answer

Dissolving salt in water

Answer

Melting of ice

Answer

Photosynthesis

Question 28

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

Accepted Answer

To decrease the activation energy

Answer

To increase the activation energy

Answer

To change the products of the reaction

Answer

To stop the reaction from occurring

Question 29

What is the primary purpose of using a titration in chemical analysis?

Accepted Answer

To determine the concentration of an unknown solution

Answer

To neutralize an acid with a base

Answer

To measure the volume of a gas

Answer

To identify an unknown substance

Question 30

Which of the following is a strong acid?

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Carbonic acid

Answer

Phosphoric acid

Question 31

What is the pH of a neutral solution?

Accepted Answer

7

Answer

0

Answer

14

Answer

28

Question 32

Which of the following is a substance that traps heat in the Earth's atmosphere?

Accepted Answer

Carbon dioxide

Answer

Oxygen

Answer

Nitrogen

Answer

Argon

Question 33

Which type of chemical reaction involves the combination of two or more substances to form a single product?

Accepted Answer

Combination

Answer

Decomposition

Answer

Displacement

Answer

Neutralization

Question 34

In a balanced chemical equation, what does the coefficient in front of a chemical formula represent?

Accepted Answer

Number of atoms

Answer

Atomic number

Answer

Relative atomic mass

Answer

Number of molecules

Question 35

Which reaction releases energy in the form of heat?

Accepted Answer

Burning of fuel

Answer

Dissolving salt in water

Answer

Melting of ice

Answer

Rusting of iron

Question 36

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

Accepted Answer

It speeds up the reaction without being consumed.

Answer

It is a reactant in the reaction.

Answer

It is a product of the reaction.

Answer

It slows down the reaction.

Question 37

Identify the precipitation reaction from the following options:

Accepted Answer

CaCO3 + 2HCl → CaCl2 + H2O + CO2

Answer

2Na + Cl2 → 2NaCl

Answer

CH4 + 2O2 → CO2 + 2H2O

Answer

2Fe + 3Cl2 → 2FeCl3

Question 38

Which substance is classified as a strong acid?

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Citric acid

Answer

Carbonic acid

Question 39

What is the name of the compound formed when an acid reacts with a base?

Accepted Answer

Salt

Answer

Ester

Answer

Alcohol

Answer

Aldehyde

Question 40

At chemical equilibrium, what happens to the concentrations of reactants and products?

Accepted Answer

The concentrations of reactants and products stay the same.

Answer

The forward reaction is much faster than the reverse reaction.

Answer

The reaction stops completely.

Answer

The system shifts towards making only products.

Question 41

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

Accepted Answer

Magnetic reaction

Answer

Neutralization reaction

Answer

Precipitation reaction

Answer

Redox reaction

Question 42

When balancing chemical equations, the coefficients represent:

Accepted Answer

The number of moles of each substance involved in the reaction

Answer

The mass of each substance involved in the reaction

Answer

The volume of each substance involved in the reaction

Question 43

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

Accepted Answer

Combustion of methane

Answer

Neutralization of hydrochloric acid with sodium hydroxide

Answer

Formation of ice from water

Answer

Dissolution of sodium hydroxide in water

Question 44

Which of the following substances acts as a reducing agent?

Accepted Answer

Fe2+

Answer

H2SO4

Answer

KCl

Answer

HCl

Question 45

The rate of a chemical reaction can be increased by:

Accepted Answer

Increasing the temperature

Answer

Adding an inhibitor

Answer

Decreasing the concentration of reactants

Answer

Removing a catalyst

Question 46

Which of these is NOT a type of chemical reaction?

Accepted Answer

Nuclear reaction

Answer

Combination reaction

Answer

Displacement reaction

Answer

Decomposition reaction

Question 47

What is the balanced chemical equation for the reaction between hydrogen and oxygen to form water?

Accepted Answer

2H2 + O2 → 2H2O

Answer

2H + O → H2O

Answer

2H + 2O → H2O

Answer

H + O2 → H2O

Question 48

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

Accepted Answer

To increase the rate of reaction without being consumed

Answer

To change the products of the reaction

Answer

To decrease the rate of reaction without being consumed

Answer

To be consumed and produce a new product

Question 49

Which of the following is a characteristic of a reversible chemical reaction?

Accepted Answer

The reaction can proceed in both directions

Answer

The equilibrium position lies far to one side

Answer

The reaction is catalyzed by an enzyme

Answer

The reaction always proceeds to completion

Question 50

Which of the following is an example of a displacement reaction?

Accepted Answer

Iron reacting with copper sulfate solution

Answer

Sodium chloride dissolving in water

Answer

Hydrogen reacting with oxygen

Answer

Carbon dioxide reacting with calcium hydroxide

Question 51

Which of the following is a strong electrolyte?

Accepted Answer

Sodium chloride

Answer

Ammonia

Answer

Acetic acid

Answer

Sucrose

Question 52

What is the pH of a solution with a hydrogen ion concentration of 1 x 10^-7 M?

Accepted Answer

7

Answer

14

Answer

0

Answer

1 x 10^-7