Integrated Science — MCQ Practice

A dichotomous key is used to identify an unknown organism. Which statement describes how such a key works?

A. It lists every known organism in Singapore in a single table.

B. At each step it offers two choices, and the choice made narrows the group further.

C. It groups organisms according to the habitat in which they are found.

D. It can only be used to identify animals that have a backbone.

A rectangular metal block measures 6.0 cm by 4.0 cm by 2.5 cm and has a mass of 480 g. What is the density of the metal?

A. 4.0 g/cm³

B. 6.0 g/cm³

C. 8.0 g/cm³

D. 12.0 g/cm³

A stone of mass 55 g is lowered into a measuring cylinder containing 40 cm³ of water. The water level rises to 62 cm³. What is the density of the stone?

A. 1.4 g/cm³

B. 2.5 g/cm³

C. 2.8 g/cm³

D. 0.89 g/cm³

Which observation shows that a sample of water is pure?

A. It boils over a range of temperatures from 96 °C to 100 °C.

B. It freezes at exactly 0 °C.

C. It leaves a white residue behind when it is evaporated to dryness.

D. Blue litmus paper turns red when dipped into it.

A beaker contains sea water with sand suspended in it. Which sequence separates the sand first and then recovers the dissolved salt?

A. Evaporation, then filtration.

B. Filtration, then evaporation of the filtrate.

C. Distillation, then filtration.

D. Filtration, then adding more water.

A student views a specimen using a microscope with a x10 eyepiece and a x40 objective lens. What is the total magnification?

A. 50

B. 400

C. 4000

D. 40

Smoke particles trapped in a brightly lit cell are seen to move in a random zig-zag manner. Why do they move in this way?

A. The smoke particles are attracted towards the light source.

B. Air particles move randomly and collide unevenly with the smoke particles.

C. The smoke particles have very low melting points.

D. Heat from the light pushes all the smoke particles steadily in one direction.

In which state of matter are the particles furthest apart and moving randomly at the highest average speed?

A. Solid

B. Liquid

C. Gas

D. The arrangement is the same in all three states.

A drop of purple dye spreads through the water faster in a beaker of hot water than in a beaker of cold water. Which statement explains this?

A. Hot water has a lower density, so the dye falls through it faster.

B. At a higher temperature the water particles have more kinetic energy and move faster, so the dye spreads more quickly.

C. The dye dissolves chemically in hot water but only mixes physically in cold water.

D. The dye particles become smaller when the water is hot.

Q10

Which of the following is a change of state of a substance?

A. A candle burning with a bright flame.

B. Iodine crystals forming a purple vapour when they are warmed gently.

C. An iron nail rusting in damp air.

D. Sugar dissolving in a cup of tea.

Q11

Two identical steel blocks, A and B, each have a mass of 1 kg. Block A is at 45 °C and block B is at 78 °C. Which statement is correct?

A. Both blocks contain the same thermal energy.

B. Block A contains more thermal energy than block B.

C. Block B contains more thermal energy, and the average kinetic energy of its particles is greater.

D. The average kinetic energy of the particles in block A is greater.

Q12

Which two gases are the main greenhouse gases responsible for global warming?

A. Methane and carbon dioxide.

B. Sulfur dioxide and nitrogen dioxide.

C. Ozone and nitrogen.

D. Carbon monoxide and sulfur dioxide.

Q13

Which gas released by the burning of fossil fuels is mainly responsible for acid rain?

A. Carbon dioxide

B. Methane

C. Sulfur dioxide

D. Nitrogen

Q14

Car exhaust fumes contain carbon monoxide, nitrogen dioxide, sulfur dioxide, carbon dioxide, water vapour and nitrogen. Which of these are also present in unpolluted air?

A. Nitrogen only.

B. Nitrogen and water vapour only.

C. Nitrogen, carbon dioxide and water vapour only.

D. All of them.

Q15

Which particle contains the largest number of electrons?

A. Mg²+

B. F-

C. S²-

D. Ne

Q16

A particle contains 12 protons, 12 neutrons and 10 electrons. Which particle is it?

A. Mg²+

B. Na+

C. Al³+

D. Ne

Q17

Two atoms of carbon each contain 6 protons. One contains 6 neutrons and the other contains 8 neutrons. Which statement about the two atoms is correct?

A. They are atoms of two different elements.

B. They are isotopes of carbon and have the same chemical properties.

C. They have the same nucleon (mass) number.

D. They contain different numbers of electrons.

Q18

In a beam, particles of ¹H+ travelling at the same speed are deflected through an angle of 12° by an electric field. Under identical conditions, which particle would be deflected through 4°?

A. ²H+

B. ³H+

C. ⁴He²+

D. ⁶Li³+

Q19

Which statement about the formation of an ionic bond between a metal atom and a non-metal atom is correct?

A. The metal atom gains electrons to form a negative ion.

B. The metal atom loses electrons to form a positive ion, and the non-metal atom gains those electrons to form a negative ion.

C. Both atoms share a pair of electrons.

D. Neither atom changes the number of electrons it contains.

Q20

Compound X is a simple molecular compound. Which set of properties is expected of X?

A. High melting point; conducts electricity when molten.

B. Low melting point; does not conduct electricity in any state.

C. High melting point; hard and brittle.

D. Low melting point; conducts electricity when dissolved in water.

Q21

Which statement about a solid ionic compound is NOT correct?

A. It has a high melting point.

B. It is a crystalline solid at room temperature.

C. It conducts electricity in the solid state.

D. It is hard and brittle.

Q22

Which particles are responsible for conducting electricity in solid metals and in molten ionic compounds?

A. Metals: electrons. Molten ionic compounds: electrons.

B. Metals: electrons. Molten ionic compounds: positive and negative ions.

C. Metals: positive metal ions. Molten ionic compounds: electrons.

D. Metals: positive metal ions and electrons. Molten ionic compounds: positive and negative ions.

Q23

Which statement explains why graphite conducts electricity but diamond does not?

A. Graphite has weak forces between its layers, so the layers slide apart easily.

B. In graphite each carbon atom is bonded to only three others, leaving electrons that are delocalised and free to move along the layers.

C. Graphite has a giant ionic lattice containing free ions.

D. Graphite has a lower melting point than diamond.

Q24

Why can a metal be hammered into a thin sheet without breaking?

A. The atoms in a metal are held by strong covalent bonds that break and re-form.

B. Layers of positive metal ions can slide over one another, and the delocalised electrons hold the layers together.

C. A metal contains mobile positive and negative ions.

D. The particles in a metal are far apart, so the metal can be compressed.

Q25

A ray of light strikes a plane mirror at an angle of 30° to the surface of the mirror. What is the angle of reflection?

A. 30°

B. 60°

C. 90°

D. 120°

Q26

Which statement about the image formed by a plane mirror is correct?

A. It is real, and it is inverted.

B. It is virtual, the same size as the object, and laterally inverted.

C. It is smaller than the object and can be projected onto a screen.

D. It is larger than the object and upright.

Q27

A ray of light passes from air into a glass block at an angle to the surface. Which statement about the ray in the glass is correct?

A. It speeds up and bends away from the normal.

B. It slows down and bends towards the normal.

C. Its speed is unchanged and it does not bend.

D. It slows down and bends away from the normal.

Q28

Light travels at 2.0 × 10⁸ m/s in a transparent medium, and at 3.0 × 10⁸ m/s in air. What is the refractive index of the medium?

A. 0.67

B. 1.5

C. 2.0

D. 6.0

Q29

Which structure is present in a cell from a leaf but absent from a human cheek cell?

A. Cell membrane

B. Nucleus

C. Chloroplast

D. Cytoplasm

Q30

A student uses this key: 1a Has wings, go to 2. 1b No wings, go to 3. 2a Two pairs of wings, Dragonfly. 2b One pair of wings, Housefly. 3a Eight legs, Spider. 3b Six legs, Ant. An organism has six legs and no wings. Which organism is it?

A. Dragonfly

B. Housefly

C. Spider

D. Ant