CSEC Chemistry Paper 1 May/June 2025 - Free CXC Past Paper with Answers

Which of the following properties refer to an electron?

Relative Charge: -1, Approximate Mass: 0

Relative Charge: 0, Approximate Mass: 1

Relative Charge: 0, Approximate Mass: 2

Relative Charge: +1, Approximate Mass: 1

Which of the following processes does NOT provide evidence in support of the particulate nature of matter?

From which of the following substances can a solid be obtained by the process of sedimentation?

Which of the following substances consists of the cation of a base and an anion of an acid?

Which of the following pairs represents the number of neutrons and electrons in X?

Number of Neutrons: 20, Number of Electrons: 20

Number of Neutrons: 20, Number of Electrons: 18

Number of Neutrons: 60, Number of Electrons: 18

Number of Neutrons: 60, Number of Electrons: 20

What mass of neon atoms contains the same number of moles as 140 g of calcium atoms? [RAM: Ne = 20; Ca = 40]

Which of the following salts is an acid salt?

A 'weak acid' is BEST described as one that yields a

low reading on the pH meter

low concentration of acid in aqueous solution

high concentration of hydrogen ions in solution

low concentration of hydrogen ions in aqueous solution

Which of the following substances do NOT produce water when reacted with acid?

Which of the following diagrams illustrates bonding in chlorine?

Which TWO elements above, when combined with each other, form an ionic compound?

The ionic equation for the reaction between an acid and a carbonate is represented by

$2H^+(aq) + CO_3^{2-}(aq) \rightarrow HCO_3^-(aq)$

$H^+(aq) + CO_3^{2-}(aq) \rightarrow H_2CO_3(aq)$

$2H^+(aq) + CO_3^{2-}(aq) \rightarrow CO_2(g) + H_2O(l)$

$H^+(aq) + CO_3^{2-}(aq) \rightarrow CO_2(g) + H_2O(l)$

An atom has 20 electrons. When it ionizes, it has the same electronic configuration as

The salt whose solubility changes to the GREATEST extent in the temperature range 0 °C to 60 °C is

hydrated copper(II) sulfate

The mass number of an element is defined as

the number of neutrons

the number of electrons

the number of neutrons and protons

the number of electrons and neutrons

Which of the following acids is formed during intense exercise?

All of the elements shown above belong to which group of the periodic table?

Crystals of sodium chloride are BEST described as

Where does oxidation take place during electrolysis?

Which of the following is the correct formula for ammonium carbonate?

Which of the following mixtures can be referred to as a standard solution?

Iodine in 50 cm³ of ethanol

30 g of sodium chloride in water

Sodium chloride in 50 cm³ of water

30 g of iodine in 50 cm³ of ethanol

Which of the following elements exhibit allotropy?

The relative atomic mass of carbon is 1: and that of oxygen is 16. Therefore, 88 g of carbon dioxide consists of

3.1 moles of carbon dioxide

12 moles of carbon and 32 mole of oxygen

1 mole of carbon atoms an 2 moles of oxygen atoms

2 moles of carbon atoms an 4 moles of oxygen atoms

A mixture of copper(II) oxide an copper(II) sulfate is BEST separated by

distilling the mixture

heating the mixture and condensin

shaking with excess water and the filtering

shaking with excess water followe by fractional distillation

When 100 cm³ of 2 mol dm⁻³ hydrochloric acid (in excess) is added to 5.0 g of granulated zinc, hydrogen gas is evolved at a certain rate. If 5.0 g of powdered zinc were used instead, the rate of production of hydrogen gas would

increase because of the greater concentration of powdered zinc

increase because of the increased surface area of powdered zinc

decrease because of the decreased surface area of powdered zinc

decrease because of the lower solubility of powdered zinc

The Faraday constant has a value of

Which of the following occurs during the breaking of a chemical bond?

There is an exothermic reaction.

There is no energy change.

Some calcium carbonate was reacted with excess dilute hydrochloric acid. The volume of carbon dioxide evolved was recorded and plotted against time. Which of the following graphs represents this reaction?

Item 29 refers to the following sequence of reactions involving iron compounds, where I, II, III and IV represent progressive stages in the sequence. I II → FeCO, FeO Fe₂O₃ III IV →Fe2(SO4)3 → Fe(OH)3

In which stage is the oxidation state of iron increased?

Which of the following metals has become an environmental hazard because of the indiscriminate disposal of thermometers by labs and hospitals?

Which of the following metals will react MOST vigorously with dilute acid?

Which metal is MOST easily ionized?

Stainless steel is used to make utensils and surgical instruments. Which of the following is the major metal found in steel?

Which of the following is the reason for adding cryolite to pure alumina during the extraction of aluminium by electrolysis?

It lowers the melting point.

It reduces the resistance.

It reduces the current.

When copper(II) carbonate is heated alone in a dry test tube, a gas is evolved and a black residue is formed. This gas is expected to

turn red litmus blue

relight a glowing splint

decolourize acidified aqueous potassium manganate(VII)

form a white precipitate with aqueous calcium hydroxide

A suitable drying agent for the laboratory preparation of ammonia gas is

concentrated sulfuric acid

anhydrous copper sulfate

Which of the following compounds may be used to counteract the effects of acid rain on the soil?

An element that is a non-metal

is a solid at room temperature

can act as a reducing agent

forms an acidic oxide

conducts electricity

Which of the following aqueous solutions will produce a blue precipitate with aqueous sodium hydroxide?

Which of the following is NOT a method used to treat water for domestic purposes?

Which test can be used to identify an acidic gas?

Damp blue litmus paper

Damp red litmus paper turns blue.

Which of the following observations is expected when aqueous silver nitrate is added to aqueous potassium chloride?

A pungent gas is evolved.

A blue precipitate appears.

A white precipitate appears.

A brown precipitate appears.

Why is aluminium more resistant to corrosion than iron?

Aluminium oxide formed is more reactive than iron oxide formed.

Aluminium has reacted completely but iron has not reacted completely.

Aluminium oxide does not react with aluminium but iron oxide reacts with iron.

Aluminium oxide protects the aluminium but iron oxide does not protect the iron.

Which of the following properties of water explains why ice floats on the surface of a lake?

Heat of vaporization

Which of the following hydrocarbons is the MAJOR constituent of natural gas?

Item 46 refers to the fully displayed structural formulae of compounds Q, R and S shown below. H H H H H H H H-C-C H-C H-C-C-C-O-H о-и H O-C-H H H H H H H H Q R S

Which of the following correctly identifies the homologous series to which each compound belongs?

Which of the following substances is used as a monomer in addition polymerization?

When large alkane molecules are cracked, the products are a mixture of

small alkane molecules only

small alkene molecules only

large and small alkane molecules

small alkane and alkene molecules

Item 49 refers to the following chart showing the conversion of ethene to different products.

I H₂O conc. H₂SO₄ ETHENE POLYETHENE Br₂ II

The product, polyethene, is a

Which of the following features is NOT true of all homologous series of compounds?

The members of the series have the same functional group

the same general formula

similar chemical properties

the same empirical formula

Which of the following is the residue in the fractional distillation of petroleum?

Which of the following terms describes starch?

Giant ionic structure

Giant covalent structure

Simple molecular crystal

Macromolecular structure

Which of the following statements is/are true of alkenes? I. They react with KMnO₄/H⁺. II. They undergo addition reactions. III. They undergo substitution reactions.

The compound CH₃CH₂CH₂CH₂OH is called

A hydrocarbon is described as being unsaturated. This means that the

molecule has insufficient hydrogen atoms

molecule contains at least one double bond

carbon atoms in the molecule are very reactive

carbon atoms in the molecule are linked by single bonds

Which of the following compounds can be dehydrated?

Which of the following statements are true of alkanes and alkenes? I. Both alkanes and alkenes burn in air to produce carbon dioxide and water. II. Alkanes undergo substitution reactions whilst alkenes undergo addition reactions. III. Alkanes are saturated hydrocarbons, whilst alkenes are unsaturated hydrocarbons.

During the manufacture of ethanol by fermentation, the gas which is evolved

turns lime water cloudy

burns with a blue flame

relights a glowing splint

turns potassium dichromate green

Item 59 refers to the following equation.

Organic acid + Alcohol $\rightleftharpoons$ Ester + Water

The reverse reaction is known as

Which of the following are reactions of ethanoic acid?

I. It forms a salt with aqueous sodium hydroxide.

II. It liberates carbon dioxide from a carbonate.

III. It liberates hydrogen on contact with a strongly electropositive metal.

CSEC Chemistry Paper 1 May/June 2025 - Free CXC Past Paper with Answers

CSEC Chemistry Paper 1 May/June 2025 Questions