Question 1

A student is given a sample of an unknown gas. She cools the gas until it condenses into a liquid. Which change of state has occurred, and what happens to the particles during this process?
Correct answer: Condensation; particles lose energy and move closer together.

Accepted Answer

Condensation; particles lose energy and move closer together.

Question 2

Which of the following best explains why sodium chloride (NaCl) conducts electricity when molten but not when solid?
Correct answer: In the molten state, ions are free to move and carry charge.

Accepted Answer

In the molten state, ions are free to move and carry charge.

Question 3

A chemist is analyzing a sample containing two isotopes of chlorine: 75% Cl-35 (mass = 35) and 25% Cl-37 (mass = 37). What is the relative atomic mass of chlorine in this sample?
Correct answer: 35.5

Accepted Answer

35.5

Question 4

Which of the following statements about metallic bonding is correct?
Correct answer: Metallic bonding results in a lattice of positive ions surrounded by a sea of delocalized electrons.

Accepted Answer

Metallic bonding results in a lattice of positive ions surrounded by a sea of delocalized electrons.

Question 5

A student is asked to design an experiment to determine the effect of temperature on the rate of a chemical reaction. Which variable should be kept constant to ensure a fair test?
Correct answer: The concentration of the reactants

Accepted Answer

The concentration of the reactants

Question 6

Which of the following best describes the trend in reactivity of Group 1 metals as you move down the group in the Periodic Table?
Correct answer: Reactivity increases because outer electrons are more easily lost.

Accepted Answer

Reactivity increases because outer electrons are more easily lost.

Question 7

A solution of hydrochloric acid (HCl) is mixed with sodium hydroxide (NaOH). Which type of chemical reaction occurs, and what is one product formed?
Correct answer: Neutralization; water

Accepted Answer

Neutralization; water

Question 8

Which of the following is a correct safety precaution when heating a substance in a test tube during an experiment?
Correct answer: Wear safety goggles and point the open end away from yourself and others.

Accepted Answer

Wear safety goggles and point the open end away from yourself and others.

Question 9

Which of the following best explains why diamond has a very high melting point?
Correct answer: Diamond consists of a giant covalent structure with strong covalent bonds throughout.

Accepted Answer

Diamond consists of a giant covalent structure with strong covalent bonds throughout.

Question 10

A student is given a mixture of sand and salt. Which sequence of experimental techniques would best separate the two substances?
Correct answer: Filtration, evaporation

Accepted Answer

Filtration, evaporation

Question 11

Which of the following is a correct statement about isotopes?
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 12

Which of the following best describes the environmental impact of burning fossil fuels?
Correct answer: It releases carbon dioxide, contributing to global warming.

Accepted Answer

It releases carbon dioxide, contributing to global warming.

Question 13

A student is asked to calculate the empirical formula of a compound containing 40% sulfur and 60% oxygen by mass. What is the empirical formula? (S = 32, O = 16)
Correct answer: SO2

Accepted Answer

SO2

Question 14

Which of the following is a property of ionic compounds?
Correct answer: They are soluble in water and conduct electricity when molten.

Accepted Answer

They are soluble in water and conduct electricity when molten.

Question 15

During an experiment, a student observes that a metal reacts with dilute hydrochloric acid to produce a colorless gas that pops when a lit splint is applied. Which gas is produced?
Correct answer: Hydrogen

Accepted Answer

Hydrogen

Question 16

Which of the following best explains why graphite can conduct electricity, but diamond cannot?
Correct answer: Graphite has delocalized electrons that can move between layers.

Accepted Answer

Graphite has delocalized electrons that can move between layers.

Question 17

A student is asked to evaluate the accuracy of a titration experiment. Which of the following would improve the accuracy of the results?
Correct answer: Repeating the titration and calculating an average.

Accepted Answer

Repeating the titration and calculating an average.

Question 18

Which of the following best describes a redox reaction?
Correct answer: A reaction in which electrons are transferred between substances.

Accepted Answer

A reaction in which electrons are transferred between substances.

Question 19

Which of the following is a correct statement about the organization of the Periodic Table?
Correct answer: Elements are arranged in order of increasing atomic number.

Accepted Answer

Elements are arranged in order of increasing atomic number.

Question 20

A student is asked to explain why water is a good solvent for ionic compounds. Which explanation is correct?
Correct answer: Water molecules are polar and can surround and separate ions.

Accepted Answer

Water molecules are polar and can surround and separate ions.

Overview of Cambridge IGCSE Chemistry 0620 Syllabus

Study Guide - Practice Questions

Study Guide - Flashcards