Question 1

A student is asked to determine the concentration of a sodium chloride solution. She dissolves 5.85 g of NaCl (molar mass = 58.5 g/mol) in enough water to make 0.500 L of solution. What is the concentration of the solution in mol/dm³?
Correct answer: 0.200 mol/dm³

Accepted Answer

0.200 mol/dm³

Question 2

Which of the following best describes the process of electrolysis in terms of chemical change?
Correct answer: A chemical change where an electric current decomposes a compound into its elements.

Accepted Answer

A chemical change where an electric current decomposes a compound into its elements.

Question 3

Which of the following is a correct application of the equation n = m/M?
Correct answer: Determining the amount of substance in moles from a given mass and molar mass.

Accepted Answer

Determining the amount of substance in moles from a given mass and molar mass.

Question 4

A student mixes hydrochloric acid (HCl) with sodium hydroxide (NaOH) in a beaker. The temperature of the solution increases. What type of reaction is this, and what does the temperature change indicate?
Correct answer: Exothermic reaction; energy is released to the surroundings.

Accepted Answer

Exothermic reaction; energy is released to the surroundings.

Question 5

Which of the following best explains why metals are good conductors of electricity?
Correct answer: Metals have loosely held valence electrons that can move freely.

Accepted Answer

Metals have loosely held valence electrons that can move freely.

Question 6

A sample of gas is compressed from 2.0 dm³ to 1.0 dm³ at constant temperature. According to the kinetic theory, what happens to the pressure of the gas?
Correct answer: It doubles.

Accepted Answer

It doubles.

Question 7

Which of the following is a correct statement about acids, bases, and salts?
Correct answer: Acids react with bases to form water and a salt.

Accepted Answer

Acids react with bases to form water and a salt.

Question 8

A chemist needs to prepare 250 cm³ of 0.1 mol/dm³ potassium nitrate solution. How many grams of KNO₃ (molar mass = 101 g/mol) are required?
Correct answer: 0.505 g

Accepted Answer

0.505 g

Question 9

Which of the following best describes the environmental impact of excessive use of nitrogen-based fertilizers?
Correct answer: They can cause eutrophication in water bodies, leading to algal blooms.

Accepted Answer

They can cause eutrophication in water bodies, leading to algal blooms.

Question 10

Which experimental technique would be most appropriate to separate a mixture of sand and salt?
Correct answer: Filtration followed by evaporation.

Accepted Answer

Filtration followed by evaporation.

Question 11

A student is given a colorless solution and asked to identify the presence of chloride ions. Which reagent should be added, and what observation would confirm the presence of chloride ions?
Correct answer: Add silver nitrate; a white precipitate forms.

Accepted Answer

Add silver nitrate; a white precipitate forms.

Question 12

Which of the following statements about the Periodic Table is correct?
Correct answer: Elements in the same group have similar chemical properties.

Accepted Answer

Elements in the same group have similar chemical properties.

Question 13

Which of the following is an example of a redox reaction?
Correct answer: Zinc reacts with copper(II) sulfate to form zinc sulfate and copper.

Accepted Answer

Zinc reacts with copper(II) sulfate to form zinc sulfate and copper.

Question 14

A solution contains 0.25 mol of solute in 500 cm³ of solution. What is the concentration in mol/dm³?
Correct answer: 0.50 mol/dm³

Accepted Answer

0.50 mol/dm³

Question 15

Which of the following best describes the difference between an element and a compound?
Correct answer: An element contains only one type of atom, while a compound contains two or more types of atoms chemically bonded.

Accepted Answer

An element contains only one type of atom, while a compound contains two or more types of atoms chemically bonded.

Question 16

Which of the following is a correct safety practice in the laboratory?
Correct answer: Always add acid to water, not water to acid.

Accepted Answer

Always add acid to water, not water to acid.

Question 17

Which of the following best explains why carbon forms a vast number of organic compounds?
Correct answer: Carbon atoms can form four covalent bonds, allowing for a variety of structures.

Accepted Answer

Carbon atoms can form four covalent bonds, allowing for a variety of structures.

Question 18

A reaction is carried out in a closed system and the mass of the system is measured before and after the reaction. The mass remains unchanged. Which law does this observation support?
Correct answer: Law of Conservation of Mass

Accepted Answer

Law of Conservation of Mass

Question 19

Which of the following is a correct use of scientific conventions in chemical equations?
Correct answer: Using state symbols such as (s), (l), (g), and (aq) to indicate physical states.

Accepted Answer

Using state symbols such as (s), (l), (g), and (aq) to indicate physical states.

Question 20

Which of the following best illustrates the importance of chemistry in society?
Correct answer: Development of new medicines to treat diseases.

Accepted Answer

Development of new medicines to treat diseases.

Overview of Cambridge IGCSE Chemistry 0620 Syllabus

Study Guide - Practice Questions

Study Guide - Flashcards