1 Table 1 shows the melting points and boiling points of several chemical substances. | Substance | Melting point (°C) | Boiling point (°C) | |---|---|---| | P | −63.5 | 61.2 | | Q | −111.6 | 12.7 | | R | −218.8 | −183 | | S | 80 | 218 | Which of the following substances is in a liquid state at room temperature? flag bookmark A P B Q C R D S T4 Chapter 2.1 Basic Concepts of Matter At room temperature (about 25 °C), P is liquid because its melting point (−63.5 °C) is below 25 °C and its boiling point (61.2 °C) is above 25 °C.
2 Which of the following is a transition element? flag bookmark A Sodium B Calcium C Zinc D Neon T4 Chapter 4.7 Transition Elements Zinc is located in the d-block of the Periodic Table, so it is a transition element. Sodium, calcium, and neon are not in the d-block.
3 Choose the statement that describes one of the chemical properties of alkalis. flag bookmark A Reacts with ammonium salts to release ammonia gas B Produces hydrogen gas when reacting with reactive metals C Causes metal corrosion D Reacts with carbonate salts to produce carbon dioxide gas T4 Chapter 6.4 Chemical Properties of Acids and Alkalis Alkalis release ammonia gas when heated with ammonium salts, a key chemical property that distinguishes them from acids.
4 Diagram 1 shows the electron arrangement of the X²⁺ ion. Which of the following is the position of element X in the Periodic Table of Elements? flag bookmark A A B B C C D D T4 Chapter 4.2 The Arrangement in the Periodic Table of Elements The X²⁺ ion has 10 electrons, so atom X has 12 electrons with arrangement 2.8.2. That gives 2 valence electrons in three shells, placing X in Group 2, Period 3 — position B.
5 Which of the following salts is insoluble in water? flag bookmark A Lead(II) sulphate B Potassium sulphate C Copper(II) sulphate D Sodium sulphate T4 Chapter 6.9 Preparation of Salts Lead(II) sulphate is insoluble in water, while potassium, copper(II), and sodium sulphates are all soluble.
6 Table 2 shows the observations on blue litmus paper in three solutions. | Solution | Observation | |---|---| | Glacial ethanoic acid | No change in the colour of blue litmus paper | | Glacial ethanoic acid + propanone | No change in the colour of blue litmus paper | | Glacial ethanoic acid + water | Blue litmus paper turns red | Based on the observations, choose the correct statement. flag bookmark A Glacial ethanoic acid is a weak acid B Propanone is a universal solvent C Litmus paper does not react with glacial ethanoic acid D Acids show their acidic properties in the presence of water T4 Chapter 6.1 The Role of Water in Showing Acidic and Alkaline Properties Glacial ethanoic acid shows acidic properties only when water is present, as seen when it turns blue litmus red only after water is added.
7 Which of the following substances accelerates the coagulation of rubber? flag bookmark A Ethanoic acid B Ammonia C Ethyl ethanoate D Sodium chloride T5 Chapter 4.2 Natural Rubber Ethanoic acid is an acid that neutralizes the negative charges on rubber latex particles, causing them to coagulate and solidify.
8 Diagram 2 shows the hydrogen ion and thiosulphate ion particles in experiments I and II. Which of the following statements shows the difference in the rate of reaction for the two sets of experiments? flag bookmark A The number of thiosulphate ions decreases more rapidly in experiment I B The kinetic energy of the particles in experiment I is higher C The frequency of collisions between thiosulphate ions and hydrogen ions is higher in experiment II D The activation energy in experiment II is higher T4 Chapter 7.2 Factors Affecting Rate of Reactions T4 Chapter 7.4 Collision Theory Experiment II contains more hydrogen ions, so the frequency of collisions between thiosulphate ions and hydrogen ions is higher, increasing the rate of reaction.
9 Diagram 3 shows one use of substance X in daily life. What property of substance X makes it suitable for this use? flag bookmark A Waterproof B Resistant to corrosion C Hard and strong D High tensile strength T4 Chapter 8.1 Alloy and Its Importance Substance X is a brick, which forms the walls and bears the weight of the building. So it must be hard and strong to withstand the load and pressure without breaking.
10 A resident in Kampung Sentosa made a complaint to the Water Department because his water bill increased drastically. The officer of the department found an underground water pipe leakage in the house area by using a detector. What is the substance in the detector used by the officer? flag bookmark A Carbon-14 B Cobalt-60 C Phosphorus-32 D Sodium-24 T4 Chapter 2.4 Isotopes and Its Uses Sodium-24 is a radioactive tracer that dissolves in water, so it travels with the leaking water and emits gamma rays detectable from above ground, pinpointing the underground pipe leak.