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BGCSE Chemistry 0570 study materials
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BGCSE Chemistry 0570 practice questions

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Question 1Particulate nature of matter, states of matter and kinetic theory

Which statement best describes the particles in a solid?

  1. They are far apart and held in fixed positions.
  2. They are closely packed and move freely past one another.
  3. They are closely packed and vibrate about fixed positions. Correct answer.
  4. They are far apart and move randomly at high speed.

Explanation

In a solid the particles are held close together by strong forces and can only vibrate about fixed positions, which is why a solid keeps its own shape and volume. The other descriptions apply to liquids or gases, where particles can slide past each other or move freely through space.

Question 2Particulate nature of matter, states of matter and kinetic theory

A gas is compressed into a smaller volume at constant temperature. Which statement explains why this is possible?

  1. There are large empty spaces between the gas particles. Correct answer.
  2. The particles lose their kinetic energy and stop moving.
  3. The particles change into a liquid during compression.
  4. The gas particles themselves shrink when squeezed.

Explanation

A gas is mostly empty space because its particles are far apart compared with their own size. Squeezing pushes the particles closer together into the available space without changing the particles themselves.

Question 3Particulate nature of matter, states of matter and kinetic theory

Which change of state is described as sublimation?

  1. A gas turning directly into a solid
  2. A liquid turning into a gas at its boiling point
  3. A solid turning directly into a gas Correct answer.
  4. A solid turning into a liquid at its melting point

Explanation

Sublimation is the direct change from solid to gas without passing through the liquid state. The reverse process, gas to solid, is called deposition, while melting and boiling involve the liquid state.

Question 4Particulate nature of matter, states of matter and kinetic theory

A sealed syringe contains air at room temperature. The plunger is pushed in slowly while the temperature stays the same. What happens to the pressure of the air inside?

  1. It increases because the particles hit the walls more often. Correct answer.
  2. It stays the same because the number of particles is unchanged.
  3. It decreases because the particles move more slowly.
  4. It increases because the particles become larger.

Explanation

Reducing the volume at constant temperature means the same particles occupy less space, so they strike the walls more frequently per unit area. More frequent collisions produce a greater pressure, as described by Boyle's law.

Question 5Particulate nature of matter, states of matter and kinetic theory

Which property is characteristic of a liquid but not of a gas?

  1. It has a fixed volume but takes the shape of its container. Correct answer.
  2. It has particles that are very far apart.
  3. It fills completely any container it is placed in.
  4. It can be compressed easily into a smaller volume.

Explanation

A liquid has particles close together with enough freedom to slide, giving a fixed volume but no fixed shape. Gases instead spread to fill their container and are easily compressed because their particles are widely spaced.

Question 6Particulate nature of matter, states of matter and kinetic theory

When a liquid evaporates from an open dish, which statement is correct?

  1. The average speed of the remaining particles increases permanently.
  2. Only the fastest-moving particles leave the surface. Correct answer.
  3. The particles leave only when the dish is heated.
  4. The liquid must be at its boiling point first.

Explanation

Evaporation happens at any temperature because some surface particles have enough kinetic energy to escape the liquid. Removing the fastest particles lowers the average energy of those left, which is why evaporation cools the liquid.

Question 7Particulate nature of matter, states of matter and kinetic theory

Which statement about the particles in a gas is correct?

  1. They are attracted strongly enough to keep a fixed shape.
  2. They are in constant random motion and collide with each other. Correct answer.
  3. They are held in fixed positions and vibrate.
  4. They are arranged in a regular lattice.

Explanation

Gas particles move rapidly and randomly in straight lines until they collide with each other or with the container walls. The collisions are elastic, and the forces between particles are negligible compared with those in solids and liquids.

Question 8Particulate nature of matter, states of matter and kinetic theory

A balloon is taken from a warm room into a cold refrigerator. Assuming the pressure stays the same, what happens to the volume of the balloon?

  1. It decreases because the particles move more slowly. Correct answer.
  2. It increases because the particles move faster.
  3. It decreases because the particles themselves contract.
  4. It stays the same because the number of particles is fixed.

Explanation

Cooling lowers the average kinetic energy of the gas particles, so they collide with the walls less forcefully and less often. At constant pressure the volume must fall, in line with Charles's law.

Question 9Particulate nature of matter, states of matter and kinetic theory

A sample of ice at 0 °C is heated until it has completely melted into water at 0 °C. Which statement describes what happens to the energy supplied?

  1. It is used to break the forces between particles without changing the temperature. Correct answer.
  2. It is stored as extra kinetic energy in the water particles.
  3. It raises the temperature of the ice steadily throughout.
  4. It is lost because melting does not require energy.

Explanation

During melting the temperature stays constant at the melting point. The energy supplied is used to overcome the forces holding the particles in the solid lattice, allowing them to move past one another.

Question 10Particulate nature of matter, states of matter and kinetic theory

Which observation provides the strongest evidence that matter is made of particles?

  1. A gas can be compressed more easily than a liquid. Correct answer.
  2. A solid has a fixed melting point.
  3. A liquid has a fixed volume.
  4. A crystal has a regular shape.

Explanation

The large difference in compressibility between gases and liquids is explained by the spacing between particles, with gases having much empty space. This behaviour is direct evidence for a particulate model of matter.

Question 11Particulate nature of matter, states of matter and kinetic theory

Ammonia gas and hydrogen chloride gas are released at opposite ends of a long glass tube. A white ring of ammonium chloride forms nearer to the hydrogen chloride end. Which conclusion follows?

  1. Ammonia particles are heavier and move more slowly.
  2. Hydrogen chloride particles do not move at all.
  3. Both gases diffuse at the same speed.
  4. Ammonia particles move faster and travel further. Correct answer.

Explanation

The ring forms where the two gases meet, and it appears closer to the hydrogen chloride end, so ammonia has travelled further in the same time. Lighter ammonia particles diffuse faster than heavier hydrogen chloride particles.

Question 12Particulate nature of matter, states of matter and kinetic theory

A small crystal of purple potassium manganate(VII) is placed in a beaker of water and left. After some hours the whole water is evenly purple. Which process explains this?

  1. Convection currents caused by heating
  2. Sedimentation of the crystal to the bottom
  3. Diffusion of particles from high to low concentration Correct answer.
  4. Sublimation of the crystal into a gas

Explanation

Particles of the coloured substance move randomly and spread from where they are concentrated to regions of lower concentration until evenly mixed. This spreading is diffusion, and it occurs without stirring or heating.

Question 13Particulate nature of matter, states of matter and kinetic theory

Which change would increase the rate of diffusion of a gas through another gas?

  1. Increasing the molar mass of the gas
  2. Increasing the pressure by halving the volume at constant temperature
  3. Cooling the mixture to a low temperature
  4. Raising the temperature of the mixture Correct answer.

Explanation

Higher temperature gives particles greater average kinetic energy, so they move faster and mix more quickly. Diffusion rate depends on speed, which increases with temperature.

Question 14Particulate nature of matter, states of matter and kinetic theory

A liquid is heated steadily and its temperature is recorded. The temperature rises, then stays constant for several minutes before rising again. What is happening during the constant period?

  1. The liquid is being heated without absorbing energy.
  2. The particles have stopped moving completely.
  3. The liquid is boiling and the energy is used to separate the particles. Correct answer.
  4. The thermometer has reached its maximum reading.

Explanation

A plateau on a heating curve marks a change of state, here boiling. The energy supplied overcomes the forces between liquid particles, turning them into gas without raising the temperature.

Question 15Particulate nature of matter, states of matter and kinetic theory

Which statement correctly compares the forces between particles in the three states of the same substance?

  1. Strongest in the solid, weakest in the gas Correct answer.
  2. Strongest in the gas, weakest in the solid
  3. Strongest in the liquid, weakest in the solid
  4. Equal in all three states

Explanation

In a solid the particles are held closely in fixed positions by the strongest forces, whereas in a gas the particles are far apart and the forces between them are negligible. Liquids lie between the two.

Question 16Particulate nature of matter, states of matter and kinetic theory

A fixed mass of gas has a pressure of 100 kPa at 300 K. It is heated to 600 K at constant volume. What is the new pressure?

  1. 400 kPa
  2. 100 kPa
  3. 200 kPa Correct answer.
  4. 50 kPa

Explanation

At constant volume, pressure is directly proportional to absolute temperature, so doubling the temperature from 300 K to 600 K doubles the pressure. The new pressure is therefore 200 kPa.

Question 17Particulate nature of matter, states of matter and kinetic theory

Why does a gas exert pressure on the walls of its container?

  1. The particles are at rest and push steadily on the walls.
  2. The particles collide with the walls and change momentum. Correct answer.
  3. The particles dissolve into the walls of the container.
  4. The particles are attracted to the walls and stick to them.

Explanation

Gas particles move randomly and strike the container walls many times each second. Each collision exerts a small force, and the total force per unit area is the pressure of the gas.

Question 18Particulate nature of matter, states of matter and kinetic theory

A sample of gas in a cylinder is compressed slowly at constant temperature. Which statement about the particles is correct?

  1. Their average speed becomes zero at high pressure.
  2. Their average speed decreases because the volume is smaller.
  3. Their average speed stays the same but they collide with the walls more often. Correct answer.
  4. Their average speed increases because they are squeezed.

Explanation

Temperature determines average kinetic energy, so at constant temperature the average speed is unchanged. Because the particles are packed into a smaller volume, they strike the walls more frequently, raising the pressure.

Question 19Particulate nature of matter, states of matter and kinetic theory

Two identical sealed flasks contain equal numbers of gas particles at the same temperature, but one gas has heavier particles. Which statement is correct?

  1. The lighter gas exerts a greater pressure because its particles move faster.
  2. Both gases exert the same pressure because pressure depends on collision rate and momentum transfer, which balance out. Correct answer.
  3. The pressures cannot be compared without knowing the flask volumes.
  4. The heavier gas exerts a greater pressure because its particles are heavier.

Explanation

At the same temperature both gases have the same average kinetic energy. The heavier particles move more slowly but transfer more momentum per collision, and these two effects exactly cancel so the pressures are equal.

Question 20Particulate nature of matter, states of matter and kinetic theory

A sample of gas has a volume of 200 cm³ at 27 °C and 1.0 atm. It is heated to 327 °C while the pressure is kept at 1.0 atm. What is the new volume?

  1. 200 cm³
  2. 400 cm³ Correct answer.
  3. 300 cm³
  4. 600 cm³

Explanation

Temperatures must be converted to kelvin: 27 °C is 300 K and 327 °C is 600 K. At constant pressure the volume is directly proportional to absolute temperature, so doubling the temperature doubles the volume to 400 cm³.

Question 21Particulate nature of matter, states of matter and kinetic theory

A gas is cooled at constant pressure until it condenses to a liquid. Which description of the particles is correct?

  1. They lose kinetic energy and become held close together by attractive forces. Correct answer.
  2. They break apart into smaller particles during condensation.
  3. They gain kinetic energy and move further apart.
  4. They stop moving completely once the liquid forms.

Explanation

Cooling removes kinetic energy, so the particles slow down until the attractive forces between them can hold them close together in the liquid state. The particles themselves remain unchanged.

Question 22Particulate nature of matter, states of matter and kinetic theory

A balloon filled with air is placed under a vacuum jar and the air around it is removed. The balloon expands and may burst. Which explanation is correct?

  1. The balloon material becomes weaker in a vacuum.
  2. The pressure outside the balloon falls, so the greater internal pressure pushes the balloon outwards. Correct answer.
  3. The particles inside the balloon increase in number.
  4. The gas inside the balloon gains energy from the vacuum.

Explanation

A balloon stays inflated because the gas inside pushes outwards and the surrounding air pushes inwards. Removing the outside air removes the inward pressure, so the internal pressure makes the balloon expand until it bursts.

Question 23Particulate nature of matter, states of matter and kinetic theory

A liquid in an open container is warmed gently. Which statement best explains why the rate of evaporation increases?

  1. The forces between the particles become stronger.
  2. The particles of the liquid become lighter as they warm up.
  3. The boiling point of the liquid falls to room temperature.
  4. A greater fraction of particles now have enough energy to escape from the surface. Correct answer.

Explanation

Evaporation requires surface particles to have enough kinetic energy to overcome the attractive forces holding them in the liquid. Warming increases the average kinetic energy, so a larger fraction of particles can escape.

Question 24Particulate nature of matter, states of matter and kinetic theory

A sealed rigid container holds a gas at 25 °C. The container is heated to 200 °C. Which statement about the particles is correct?

  1. Their number increases as the temperature rises.
  2. Their average speed stays the same because the volume is fixed.
  3. Their average speed increases and they collide with the walls more forcefully. Correct answer.
  4. They arrange themselves into a regular lattice.

Explanation

Heating raises the average kinetic energy of the gas particles, so they move faster and strike the walls with greater momentum and more often. Since the volume is fixed, the pressure rises.

Question 25Atomic structure, the Periodic Table and chemical bonding

An atom of an element has 11 protons, 12 neutrons and 11 electrons. What is the mass number of this atom?

  1. 12
  2. 34
  3. 11
  4. 23 Correct answer.

Explanation

The mass number is the total number of protons plus neutrons in the nucleus, so 11 + 12 = 23. Electrons are not included because their mass is negligible compared with nucleons.

Question 26Atomic structure, the Periodic Table and chemical bonding

Which statement describes the arrangement of particles in a solid ionic compound such as sodium chloride?

  1. Discrete molecules with shared electron pairs
  2. Small neutral atoms held by van der Waals forces
  3. A sea of delocalised electrons around positive ions
  4. A regular lattice of alternating positive and negative ions Correct answer.

Explanation

Ionic compounds form a giant lattice in which each cation is surrounded by anions and vice versa, giving a regular repeating pattern. The strong electrostatic attraction between oppositely charged ions holds the lattice together.

Question 27Atomic structure, the Periodic Table and chemical bonding

How many electrons are in the outer shell of a chlorine atom (atomic number 17)?

  1. 8
  2. 1
  3. 17
  4. 7 Correct answer.

Explanation

Chlorine's electron configuration is 2, 8, 7, so the outer shell holds seven electrons. Elements in Group VII of the periodic table all have seven outer-shell electrons.

Question 28Atomic structure, the Periodic Table and chemical bonding

Which type of bond forms when a sodium atom transfers its single outer electron to a chlorine atom?

  1. Hydrogen bond
  2. Ionic bond Correct answer.
  3. Covalent bond
  4. Metallic bond

Explanation

Transfer of electrons from a metal to a non-metal produces oppositely charged ions that attract each other electrostatically. This electrostatic attraction between ions is an ionic bond.

Question 29Atomic structure, the Periodic Table and chemical bonding

Which group of the periodic table contains the noble gases?

  1. Group 2
  2. Group 0 Correct answer.
  3. Group 7
  4. Group 1

Explanation

The noble gases occupy Group 0 (also called Group 18), on the far right of the table. Their full outer shells make them very unreactive.

Question 30Atomic structure, the Periodic Table and chemical bonding

Which particle is found in the nucleus of an atom and carries no electric charge?

  1. Ion
  2. Electron
  3. Proton
  4. Neutron Correct answer.

Explanation

The nucleus contains protons and neutrons; the neutron is electrically neutral. Protons are positively charged and electrons orbit outside the nucleus.

Question 31Atomic structure, the Periodic Table and chemical bonding

Why do atoms of the same element have the same chemical properties?

  1. They contain the same number of protons and the same electron arrangement Correct answer.
  2. They have the same mass number
  3. They always contain the same number of neutrons and protons combined
  4. They contain the same number of neutrons

Explanation

Chemical behaviour depends on the number and arrangement of electrons, which is determined by the proton count. Atoms of one element share the same atomic number, so their electron configurations match.

Question 32Atomic structure, the Periodic Table and chemical bonding

A covalent bond between two atoms is best described as:

  1. A weak force between molecules
  2. A transfer of one electron from one atom to another
  3. A shared pair of electrons Correct answer.
  4. An attraction between two nuclei

Explanation

In covalent bonding, two atoms each contribute an electron to form a shared pair. The shared pair is attracted to both nuclei, holding the atoms together.

Question 33Atomic structure, the Periodic Table and chemical bonding

Magnesium has atomic number 12 and relative atomic mass 24.3. Which statement about magnesium is correct?

  1. Magnesium atoms have 12 electrons in the outer shell
  2. Most magnesium atoms contain 12 neutrons and 12 protons Correct answer.
  3. A magnesium atom contains 24 protons
  4. Every magnesium atom contains exactly 12 neutrons

Explanation

With atomic number 12 and mass number 24, the most common isotope has 12 protons and 12 neutrons. The relative atomic mass of 24.3 reflects a small proportion of heavier isotopes.

Question 34Atomic structure, the Periodic Table and chemical bonding

Potassium chloride contains K+ and Cl- ions. What is the formula of potassium chloride?

  1. KCl2
  2. K2Cl
  3. KCl Correct answer.
  4. K2Cl2

Explanation

The charges on K+ and Cl- are equal and opposite, so one ion of each balances electrically. The simplest formula is therefore KCl.

Question 35Atomic structure, the Periodic Table and chemical bonding

Which property is typical of a substance with a giant covalent structure such as diamond?

  1. It conducts electricity when solid
  2. It is soluble in water
  3. It has a low melting point
  4. It has a very high melting point Correct answer.

Explanation

In a giant covalent structure, every atom is joined to others by strong covalent bonds throughout the lattice. Breaking these bonds requires a large amount of energy, giving a very high melting point.

Question 36Atomic structure, the Periodic Table and chemical bonding

An element is in Group 2 and Period 3 of the periodic table. Which element is it?

  1. Aluminium
  2. Calcium
  3. Sodium
  4. Magnesium Correct answer.

Explanation

Period 3 begins with sodium in Group 1, so the Group 2 element in that period is magnesium. Calcium is also in Group 2 but lies in Period 4.

Question 37Atomic structure, the Periodic Table and chemical bonding

Why does the reactivity of the Group 1 metals increase down the group?

  1. The atoms become more electronegative down the group
  2. The outer electron is lost more easily as the atom gets larger Correct answer.
  3. The atoms have more outer electrons lower down the group
  4. The melting point of the metal decreases down the group

Explanation

Going down Group 1, the outer electron is further from the nucleus and shielded by more inner shells. It is therefore lost more readily, making the metal more reactive.

Question 38Atomic structure, the Periodic Table and chemical bonding

Which pair of elements would most readily form an ionic compound with each other?

  1. Two Group 7 non-metals
  2. A Group 1 metal and a Group 7 non-metal Correct answer.
  3. Two non-metals from Group 6 and Group 7
  4. A Group 4 element and hydrogen

Explanation

Ionic bonding occurs when a metal transfers electrons to a non-metal. A Group 1 metal loses one electron easily while a Group 7 non-metal gains one readily.

Question 39Atomic structure, the Periodic Table and chemical bonding

Chlorine exists as two isotopes, 35Cl and 37Cl, in roughly a 3:1 ratio. What is the relative atomic mass of chlorine to the nearest whole number?

  1. 35
  2. 37
  3. 72
  4. 36 Correct answer.

Explanation

The weighted mean is (3 × 35 + 1 × 37) ÷ 4 = 142 ÷ 4 = 35.5, which rounds to 36. Relative atomic mass is the average taking isotope abundance into account.

Question 40Atomic structure, the Periodic Table and chemical bonding

Solid sodium chloride does not conduct electricity, but molten sodium chloride does. What is the best explanation?

  1. Molten sodium chloride contains covalent molecules that carry charge
  2. Melting breaks the lattice so ions become free to move Correct answer.
  3. Solid sodium chloride contains no charged particles
  4. Melting produces free electrons in the liquid

Explanation

In the solid lattice, ions are held in fixed positions and cannot move. Melting releases them so that they can migrate towards the electrodes and carry current.

Question 41Atomic structure, the Periodic Table and chemical bonding

Which statement correctly compares the size of a sodium atom with its ion, Na+?

  1. The Na+ ion is smaller because the atom has lost its outer shell Correct answer.
  2. The Na+ ion and the atom are the same size because only an electron is lost
  3. The Na+ ion is smaller because it has gained an electron
  4. The Na+ ion is larger because it has gained a positive charge

Explanation

A sodium atom has the configuration 2, 8, 1; losing the outer electron leaves 2, 8. Removing a whole shell reduces the radius, and the same nuclear charge now pulls fewer electrons more strongly.

Question 42Atomic structure, the Periodic Table and chemical bonding

Why is the melting point of magnesium oxide (MgO) much higher than that of sodium chloride (NaCl)?

  1. NaCl has a giant covalent structure
  2. MgO has a simple molecular structure
  3. The ions in MgO carry higher charges, so the attraction is stronger Correct answer.
  4. MgO contains covalent bonds between molecules

Explanation

MgO is built from Mg2+ and O2- ions, while NaCl contains singly charged Na+ and Cl- ions. Higher ionic charges give much stronger electrostatic attraction, so more energy is needed to melt the lattice.

Question 43Atomic structure, the Periodic Table and chemical bonding

An atom of an element has the electron configuration 2, 8, 6. In which group and period does the element lie?

  1. Group 6, Period 3 Correct answer.
  2. Group 6, Period 2
  3. Group 16, Period 2
  4. Group 2, Period 6

Explanation

Three occupied shells mean the element is in Period 3. The six outer-shell electrons place it in Group 6 (also numbered 16 in the modern system).

Question 44Atomic structure, the Periodic Table and chemical bonding

Why does graphite conduct electricity while diamond does not?

  1. Diamond has a molecular structure with mobile electrons
  2. Diamond contains free protons
  3. Graphite contains ions that can move
  4. Graphite has delocalised electrons between its layers of atoms Correct answer.

Explanation

In graphite, each carbon atom bonds to three others, leaving one electron per atom delocalised and free to move along the layers. In diamond all four outer electrons are used in bonding, so none are free to carry current.

Question 45Atomic structure, the Periodic Table and chemical bonding

Which observation best supports the idea that electrons occupy discrete energy levels rather than being spread continuously?

  1. Atoms of an element are electrically neutral
  2. Atoms of an element emit light only at certain fixed wavelengths Correct answer.
  3. Atoms of different elements have different masses
  4. The nucleus contains both protons and neutrons

Explanation

Line spectra show that electrons can only move between specific energy levels, emitting photons of fixed energy and hence fixed wavelength. A continuous spread of energies would give a continuous spectrum instead.

Question 46Atomic structure, the Periodic Table and chemical bonding

An atom of element X forms a 2+ ion with the electron configuration 2, 8. What is the atomic number of X?

  1. 12 Correct answer.
  2. 14
  3. 10
  4. 8

Explanation

The 2+ ion has 10 electrons, so the neutral atom must have 12 electrons and therefore 12 protons. The configuration of the neutral atom is 2, 8, 2, which is magnesium.

Question 47Atomic structure, the Periodic Table and chemical bonding

Successive ionisation energies of an element are 590, 1150, 4940 and 6480 kJ/mol. Which group is the element most likely to be in?

  1. Group 1
  2. Group 3
  3. Group 2 Correct answer.
  4. Group 4

Explanation

The large jump occurs between the second and third ionisation energies, meaning a third electron must be removed from a new, inner shell. Two relatively easy removals indicate two outer-shell electrons, so the element is in Group 2.

Question 48Atomic structure, the Periodic Table and chemical bonding

Why is the first ionisation energy of magnesium higher than that of sodium?

  1. Magnesium has a full outer shell
  2. Magnesium has more electron shells than sodium
  3. Magnesium has a greater nuclear charge with the outer electron in the same shell Correct answer.
  4. Magnesium has a larger atomic radius than sodium

Explanation

Both elements lose an electron from the third shell, but magnesium has one more proton. The greater nuclear charge pulls the outer electron more strongly without adding a new shell, so more energy is needed to remove it.

Question 49Atomic structure, the Periodic Table and chemical bonding

Two atoms have the same electron configuration but different nuclear charges. Which statement about them is necessarily true?

  1. They have the same number of protons
  2. They have the same number of neutrons
  3. They are isotopes of the same element
  4. They are ions of different elements Correct answer.

Explanation

Identical electron arrangements with different nuclear charges mean the atoms are charged species, such as Na+ and F-, which both have the configuration 2, 8. Different proton counts mean different elements.

Question 50Atomic structure, the Periodic Table and chemical bonding

An atom of fluorine has atomic number 9 and mass number 19. How many neutrons are in its nucleus?

  1. 10 Correct answer.
  2. 19
  3. 28
  4. 9

Explanation

The mass number equals the total number of protons plus neutrons, while the atomic number equals the number of protons. Subtracting the proton count from the mass number gives 19 − 9 = 10 neutrons.