1 Diagram 1 shows a safety equipment in the laboratory. What is the function of the safety equipment? flag bookmark A A specially designed equipment to carry out experiments that release toxic vapours, flammable substances or pungent smells B Used to wash and clean the body when an accident occurs on parts of the body C Used to remove chemical substances, oil, dirt and microorganisms from the hands D Used for extinguishing fire in the laboratory T4 Chapter 1.3 Usage, Management and Handling of Apparatus and Materials The equipment is a fume chamber (fume cupboard). Experiments that give off toxic, flammable or pungent vapours are carried out inside it so the vapours are drawn away from the user.
2 Diagram 2 shows the formation of dew on the leaves in the morning. What is the process and energy change involved during the formation of dew in Diagram 2? | | Process | Energy change | |---|---|---| | A | Evaporation | Energy absorbed | | B | Evaporation | Energy released | | C | Condensation | Energy absorbed | | D | Condensation | Energy released | flag bookmark A A B B C C D D T4 Chapter 2.1 Basic Concepts of Matter Dew forms when water vapour in the cool morning air changes into liquid water on the leaves. Gas to liquid is condensation, and heat energy is released as the particles move closer together.
3 The mass of one atom of element Y is two times more than an atom of chlorine. What is the relative atomic mass of element Y? [Relative atomic mass: Cl = 35.5] flag bookmark A 17.5 B 24.0 C 35.5 D 71.0 T4 Chapter 3.1 Relative Atomic Mass and Relative Molecular Mass One atom of Y is twice as heavy as one chlorine atom, so its relative atomic mass is 2 × 35.5 = 71.0.
4 Which of the following statements are correct about the physical properties of elements in Group 18 when going down the group? I The intensity of colour decreases II The attraction force between atoms increases III The density of these elements decreases IV The melting point and boiling point of these elements increase flag bookmark A I and II B I and III C II and IV D III and IV T4 Chapter 4.3 Elements in Group 18 Going down Group 18 the atoms get bigger, so the van der Waals attraction between atoms increases (II) and more energy is needed to overcome it, so the melting and boiling points increase (IV). Noble gases are colourless, and their density increases down the group.
5 Which statement is not a special characteristic of transition elements? flag bookmark A Act as catalyst B High melting and boiling points C Form coloured compounds D Have more than one oxidation number T4 Chapter 4.7 Transition Elements The special characteristics of transition elements are acting as catalysts, forming coloured compounds or ions, having more than one oxidation number and forming complex ions. High melting and boiling points are shared by most metals, so they are not special to transition elements.
6 Diagram 3 shows a type of bond. $$\text{H}_2\text{O} + \text{H}^+ \rightarrow \text{H}_3\text{O}^+$$ Which of the following is correct about the bond? flag bookmark A The force of attraction between hydrogen atoms that have bonded with an atom of high electronegativity in another molecule B A type of bond where there is an electrostatic attraction force between the sea of electrons and the positively-charged metal ions C A type of bond where the electron pairs shared come from one atom only D A bond that is formed through the transfer of electrons between metal atoms and non-metal atoms T4 Chapter 5.5 Dative Bond In the hydronium ion, the oxygen atom of water donates a lone pair of electrons to the $\text{H}^+$ ion, which has no electrons. A covalent bond in which both shared electrons come from one atom is a dative bond.
7 Which of the following are the physical characteristics of salt crystals? I Have the same volume II Have flat surfaces and straight sides III Have the same size with the same density IV Have a specific geometrical shape flag bookmark A I and II B I and III C II and IV D III and IV T4 Chapter 6.8 Salts, Crystals and Their Uses in Daily Life Salt crystals have flat surfaces, straight edges and sharp angles (II), and each salt has a specific geometrical shape (IV). Crystals of the same salt can have different sizes and volumes.
8 Which of the following is a weak alkali? flag bookmark A Aluminium hydroxide, $\text{Al(OH)}_3$ B Ammonium hydroxide, $\text{NH}_4\text{OH}$ C Barium hydroxide, $\text{Ba(OH)}_2$ D Potassium hydroxide, KOH T4 Chapter 6.3 Strength of Acids and Alkalis Aqueous ammonia (ammonium hydroxide) ionises only partially in water to produce a low concentration of $\text{OH}^-$ ions, so it is a weak alkali. Barium hydroxide and potassium hydroxide ionise completely, and aluminium hydroxide is insoluble in water.
9 Which of the following ceramics is correctly matched to its use? flag bookmark A Kaolin — Brake discs B Silicon carbide — Magnetic Resonance Imaging (MRI) machine C Zirconia — Dental implants D Alumina — Engine component T4 Chapter 8.3 Composition of Ceramics and Its Uses Zirconia is strong, hard-wearing and safe in the body, so it is used for dental implants. Silicon carbide is used for brake discs, and kaolin is used for pottery and porcelain.
10 The following are the characteristics of a substance needed to produce a new product in industry. - No electrical resistance - Works under extremely low temperatures - Transfers information at high speed What are the substances that can be used to produce the product? I Ceramics II Superconductor III Fibre optic IV Fibre glass flag bookmark A I and III B I and IV C II and III D II and IV T4 Chapter 8.4 Composite Materials and Its Importance A superconductor has no electrical resistance at extremely low temperatures (II), and fibre optics carry information as light at very high speed (III).