1 Which of the following substances is an element? flag bookmark A Steam B Sand C Gold D Naphthalene T4 Chapter 2.1 Basic Concepts of Matter Gold is an element because it is made up of only one type of atom and cannot be chemically broken down into simpler substances.
2 Diagram 2 shows a correct storage method for substance X. Which of the following matches is correct for substance X? flag bookmark A X: Chlorine; Explanation: Very corrosive material B X: Sodium; Explanation: Decomposed in presence of light C X: Iodine; Explanation: Easily volatile when exposed to heat D X: Potassium; Explanation: Prevent reaction with water T4 Chapter 1.3 Usage, Management and Handling of Apparatus and Materials Potassium is stored under paraffin oil because it reacts vigorously with water, so the oil prevents contact with moisture and air.
3 Which of the following shows the correct classification for the particles in the substances? flag bookmark A Atom: Sodium; Molecule: Carbon dioxide; Ion: Sodium chloride B Atom: Carbon dioxide; Molecule: Sodium; Ion: Sodium chloride C Atom: Sodium chloride; Molecule: Carbon dioxide; Ion: Sodium D Atom: Sodium; Molecule: Sodium chloride; Ion: Carbon dioxide T4 Chapter 2.1 Basic Concepts of Matter Sodium exists as single atoms, carbon dioxide is made of molecules, and sodium chloride consists of ions.
4 The following equation represents a chemical reaction > 2Li(s) + Cl₂(g) → 2LiCl(s) Which of the following is the most accurate statement of the ratio of the basic entities in the chemical equation? flag bookmark A Lithium reacts with chlorine to produce lithium chloride B Lithium solid reacts with chlorine gas to produce lithium chloride solid C 2 mol lithium react with 1 mol of chlorine to produce 2 mol of lithium chloride D 2 lithium atoms react with 1 molecule of chlorine to produce 2 formula units of lithium chloride T4 Chapter 3.4 Chemical Equation The equation expresses particle-level ratios: 2 lithium atoms combine with 1 chlorine molecule to form 2 formula units of lithium chloride, so D is the most accurate.
5 Which of the following statements explains why carbon-12 atom was chosen as a reference standard to determine the relative atomic mass and relative molecular mass? flag bookmark A Reacts easily with other substances B Has an accurate natural abundance C It is a solid and easier to be handle D Easily found in living and non-living things T4 Chapter 3.1 Relative Atomic Mass and Relative Molecular Mass Carbon-12 is a solid, so it is easy to weigh and handle in the laboratory. Its fixed mass of exactly 12 units makes it a stable, convenient reference standard.
6 Which of the following properties is correct when glacial ethanoic acid is dissolved in propanone? flag bookmark A Ionises to produce hydrogen ions B The solution produced does not conduct electricity C The effervescence occurs when calcium carbonate powder is added into the solution produced D A dry blue litmus paper turns red when it is put into the solution produced T4 Chapter 6.1 The Role of Water in Showing Acidic and Alkaline Properties In propanone, ethanoic acid does not ionise, so no free ions are produced and the solution cannot conduct electricity.
7 Diagram 7 shows two types of molecular structure for covalent compounds. What is the similarity of W and Y? flag bookmark A Has weak Van der Waals forces of attraction between molecules B Does not conduct electricity in any state C Has low melting and boiling points D Exists as gas at room temperature T4 Chapter 5.7 Properties of Ionic Compounds and Covalent Compounds Both are covalent compounds; without free electrons or ions, they cannot conduct electricity in any state.
8 Which of the following methods will increase the frequency of collision between particles? I Use catalyst II Increase the size of the reactant III Increase the temperature of the reaction IV Increase the concentration of the reactant flag bookmark A I and II B I and IV C II and III D III and IV T4 Chapter 7.4 Collision Theory Increasing temperature speeds up particles, raising collision frequency; increasing concentration packs more particles into the same space, so collisions happen more often. Catalyst changes reaction pathway but not collision frequency, while larger reactant size reduces surface contact.
9 Brake disc is one of the components installed in the car. Which of the following is the property of material used in the manufacture of brake discs? flag bookmark A Not chemically reactive B Has a smooth surface C High abrasion resistance D Low coefficient of expansion T4 Chapter 8.3 Composition of Ceramics and Its Uses Brake discs constantly rub against brake pads, so the material must withstand wear and friction without degrading quickly. High abrasion resistance ensures the disc lasts and brakes effectively.
10 Which of the following properties of lead crystal glass that can produced prisms and decorative glass? I High density II Low melting point III Low coefficient of thermal expansion IV High refractive index flag bookmark A I and II B I and IV C II and III D III and IV T4 Chapter 8.2 Composition of Glass and Its Uses Lead crystal glass has high density and high refractive index, which give the brilliance and light-bending ability needed for prisms and decorative glass.