Question 1

A sealed syringe contains 20.0 mL of air at 1.00 atm and 25°C. If the plunger is pushed in until the volume is halved, and the temperature remains constant, what is the new pressure inside the syringe?
Correct answer: 2.00 atm

Accepted Answer

2.00 atm

Question 2

Which of the following best explains why ionic compounds generally conduct electricity when molten but not when solid?
Correct answer: Ions are free to move in the molten state, allowing charge to flow.

Accepted Answer

Ions are free to move in the molten state, allowing charge to flow.

Question 3

A student is given a sample of an unknown metal and asked to identify it. Which property would be most useful for distinguishing between sodium and magnesium?
Correct answer: Reaction with water

Accepted Answer

Reaction with water

Question 4

Which of the following statements about isotopes is correct?
Correct answer: Isotopes of an element have the same number of protons but different numbers of neutrons.

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 5

A reaction is found to be exothermic. Which of the following is most likely to be observed during the reaction?
Correct answer: The temperature of the surroundings increases.

Accepted Answer

The temperature of the surroundings increases.

Question 6

Which of the following best describes the process of diffusion?
Correct answer: The movement of particles from an area of high concentration to an area of low concentration.

Accepted Answer

The movement of particles from an area of high concentration to an area of low concentration.

Question 7

A 10.0 g sample of calcium carbonate (CaCO₃) is decomposed by heating. How many moles of CaCO₃ are present in the sample? (Molar mass of CaCO₃ = 100 g/mol)
Correct answer: 0.10 mol

Accepted Answer

0.10 mol

Question 8

Which of the following laboratory practices is most important for ensuring safety when heating chemicals?
Correct answer: Wearing safety goggles and using tongs to handle hot equipment.

Accepted Answer

Wearing safety goggles and using tongs to handle hot equipment.

Question 9

Which of the following best explains why carbon monoxide (CO) is considered a pollutant in the environment?
Correct answer: It binds to hemoglobin in blood, reducing oxygen transport.

Accepted Answer

It binds to hemoglobin in blood, reducing oxygen transport.

Question 10

A student mixes hydrochloric acid (HCl) with sodium hydroxide (NaOH) in a beaker. Which type of reaction occurs?
Correct answer: Neutralization

Accepted Answer

Neutralization

Question 11

Which of the following best describes the trend in atomic radius across Period 3 of the Periodic Table?
Correct answer: It decreases from left to right.

Accepted Answer

It decreases from left to right.

Question 12

A sample of gas occupies 2.0 L at 300 K. If the temperature is increased to 600 K at constant pressure, what is the new volume?
Correct answer: 4.0 L

Accepted Answer

4.0 L

Question 13

Which of the following is a correct statement about covalent bonding?
Correct answer: It involves the sharing of electron pairs between atoms.

Accepted Answer

It involves the sharing of electron pairs between atoms.

Question 14

Which of the following is an example of a green chemistry practice?
Correct answer: Using catalysts to reduce energy consumption in industrial processes.

Accepted Answer

Using catalysts to reduce energy consumption in industrial processes.

Question 15

A student is asked to calculate the relative atomic mass of chlorine given the following data: 75% Cl-35 (mass = 35), 25% Cl-37 (mass = 37). What is the relative atomic mass?
Correct answer: 35.5

Accepted Answer

35.5

Question 16

Which of the following best explains why metals are good conductors of electricity?
Correct answer: They have delocalized electrons that move freely through the lattice.

Accepted Answer

They have delocalized electrons that move freely through the lattice.

Question 17

Which of the following changes would increase the rate of a chemical reaction?
Correct answer: Increasing the temperature.

Accepted Answer

Increasing the temperature.

Question 18

Which of the following is the best example of applying the mole concept in a real-world scenario?
Correct answer: Calculating the amount of fertilizer needed for a field based on the number of moles of nitrogen required.

Accepted Answer

Calculating the amount of fertilizer needed for a field based on the number of moles of nitrogen required.

Question 19

Which of the following best describes a chemical equilibrium?
Correct answer: The rates of the forward and reverse reactions are equal.

Accepted Answer

The rates of the forward and reverse reactions are equal.

Question 20

Which of the following functional groups is present in ethanol?
Correct answer: Hydroxyl group (-OH)

Accepted Answer

Hydroxyl group (-OH)

Overview of Cambridge IGCSE Chemistry 0620 Syllabus

Study Guide - Practice Questions

Study Guide - Flashcards