Chemical Reactions & Equations Quiz

Question 1

What is a chemical reaction?

Accepted Answer

A process where atoms are rearranged, breaking and forming chemical bonds to produce new substances

Answer

A change in physical state such as melting

Answer

The mixing of two substances without any change

Answer

The dissolving of a solid in liquid

Question 2

What are the signs that a chemical reaction has taken place?

Accepted Answer

Temperature change, gas production, colour change, precipitate formation, or light/sound emission

Answer

Only colour change

Answer

Only the formation of a gas

Answer

Only a change in temperature

Question 3

What is the law of conservation of mass in chemistry?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction

Answer

Mass is created during reactions

Answer

Some atoms are destroyed in reactions

Answer

Mass increases in exothermic reactions

Question 4

Balance this equation: H₂ + O₂ → H₂O

Accepted Answer

2H₂ + O₂ → 2H₂O

Answer

H₂ + O₂ → H₂O

Answer

H₂ + 2O₂ → 2H₂O

Answer

4H₂ + O₂ → 2H₂O

Question 5

What type of reaction is: acid + base → salt + water?

Accepted Answer

Neutralisation

Answer

Combustion

Answer

Oxidation

Answer

Decomposition

Question 6

What is combustion?

Accepted Answer

A rapid reaction between a fuel and oxygen that releases heat and light

Answer

The dissolving of a metal in acid

Answer

The decomposition of a compound by heat

Answer

The reaction of a metal with water

Question 7

What is an exothermic reaction?

Accepted Answer

A reaction that releases energy (heat) to surroundings

Answer

A reaction that absorbs heat from surroundings

Answer

A reaction that only occurs at high temperatures

Answer

A reaction involving explosions

Question 8

What is the chemical test for hydrogen gas?

Accepted Answer

It produces a squeaky pop with a burning splint

Answer

It turns limewater milky

Answer

It relights a glowing splint

Answer

It turns litmus paper blue

Question 9

What is the chemical test for carbon dioxide?

Accepted Answer

It turns limewater milky

Answer

It produces a squeaky pop with a lit splint

Answer

It turns damp litmus paper red

Answer

It relights a glowing splint

Question 10

What is an acid in terms of protons (Brønsted-Lowry definition)?

Accepted Answer

A substance that donates protons (H⁺ ions)

Answer

A substance that accepts protons (H⁺ ions)

Answer

A substance with a pH above 7

Answer

A substance that produces OH⁻ ions

Question 11

What is produced when a metal reacts with an acid?

Accepted Answer

A salt and hydrogen gas

Answer

Metal oxide and water

Answer

A base and oxygen

Answer

Carbon dioxide and water

Question 12

What type of reaction is: 2H₂O₂ → 2H₂O + O₂?

Accepted Answer

Decomposition

Answer

Synthesis

Answer

Combustion

Answer

Displacement

Question 13

What is a catalyst?

Accepted Answer

A substance that speeds up a reaction without being used up

Answer

A substance consumed in a reaction to make it go faster

Answer

A product of a chemical reaction

Answer

An energy source for reactions

Question 14

What is the pH scale?

Accepted Answer

A scale from 0–14 measuring how acidic or alkaline a substance is

Answer

A scale from 0–7 measuring acidity only

Answer

A scale measuring temperature of reactions

Answer

A scale measuring the concentration of salts

Question 15

What type of reaction is: Fe + CuSO₄ → FeSO₄ + Cu?

Accepted Answer

Displacement

Answer

Neutralisation

Answer

Combustion

Answer

Decomposition

Question 16

What is the word equation for the complete combustion of methane?

Accepted Answer

Methane + oxygen → carbon dioxide + water

Answer

Methane + oxygen → carbon + water

Answer

Methane + oxygen → carbon monoxide + hydrogen

Answer

Methane → carbon + hydrogen

Question 17

What is precipitation in chemistry?

Accepted Answer

The formation of an insoluble solid when two solutions are mixed

Answer

The evaporation of a solution

Answer

The dissolving of a solid in water

Answer

The decomposition of a compound

Question 18

What does 'activation energy' mean?

Accepted Answer

The minimum energy required to start a chemical reaction

Answer

The energy released in a reaction

Answer

The temperature at which a reaction occurs

Answer

The energy stored in chemical bonds

Question 19

What is oxidation in terms of electron transfer?

Accepted Answer

Loss of electrons

Answer

Gain of electrons

Answer

Gain of protons

Answer

Loss of protons

Question 20

What is the chemical formula for sulfuric acid?

Accepted Answer

H₂SO₄

Answer

HCl

Answer

HNO₃

Answer

H₃PO₄