1 **[Bonus]** 本题在原卷扫描件中缺失（漏扫），无法显示题目，作送分处理：选择任何答案都算对。 This question is missing from the original scanned paper, so it cannot be shown. It is a bonus question: any answer is marked correct. Soalan ini tiada dalam imbasan kertas asal, jadi tidak dapat dipaparkan. Soalan ini dikira bonus: sebarang jawapan dikira betul. flag bookmark A — B — C — D —
2 Which of the following substances exist as molecules? flag bookmark A Helium B Carbon C Oxygen D Platinum T4 Chapter 2.1 Basic Concepts of Matter Oxygen is made of $\text{O}_2$ molecules, two atoms joined by covalent bonds. Helium exists as single atoms, carbon (graphite or diamond) is a giant structure of atoms, and platinum is a metal made of atoms.
3 The following box shows properties of elements in the Periodic Table of Elements. - Act as a catalyst - Able to form coloured ions - Has more than one oxidation number - Forms complex ions Which group of elements fits the characteristics above? flag bookmark A Group 1 elements B Group 17 elements C Group 18 elements D Transition elements T4 Chapter 4.7 Transition Elements Acting as catalysts, forming coloured ions, having more than one oxidation number and forming complex ions are the special characteristics of transition elements.
4 Silicon dioxide, $\text{SiO}_2$ is a covalent compound with a giant molecular structure. Which of the following is a property of silicon dioxide, $\text{SiO}_2$? flag bookmark A Small and simple structure B High melting point and boiling point C Strong covalent bonds in the molecule and weak forces of attraction between molecules T4 Chapter 5.7 Properties of Ionic Compounds and Covalent Compounds In silicon dioxide every atom is held by strong covalent bonds in a giant network. A lot of heat is needed to break these bonds, so it has very high melting and boiling points. It has no separate small molecules held by weak forces.
5 Which of the following substances is acidic? flag bookmark A Ammonia B Potassium oxide C Carbon dioxide D Sodium hydroxide T4 Chapter 6.1 The Role of Water in Showing Acidic and Alkaline Properties Carbon dioxide is a non-metal oxide. It dissolves in water to form carbonic acid, which produces $\text{H}^+$ ions, so it is acidic. The other three are alkaline or basic.
6 Limestone is an insoluble salt. Which of the following salts is of the same type as limestone? flag bookmark A Potassium carbonate B Sodium carbonate C Magnesium carbonate D Ammonium carbonate T4 Chapter 6.8 Salts, Crystals and Their Uses in Daily Life Limestone (calcium carbonate) is an insoluble carbonate. Most carbonates are insoluble except those of potassium, sodium and ammonium, so magnesium carbonate is the insoluble salt.
7 Which statement best explains the meaning of effective collision? flag bookmark A Collisions that occur at high temperatures B Collisions that cause a chemical reaction to occur C Collisions that cause the formation of new bonds D Collisions that occur when reactant particles collide with each other in the correct orientation T4 Chapter 7.4 Collision Theory An effective collision is a collision that causes a chemical reaction to occur (B). For this, the particles must collide in the correct orientation and with energy equal to or more than the activation energy. D only mentions the correct orientation, so it is incomplete. (Note: the answer scheme gives D; on checking, our AI thinks B is more accurate, so both B and D are accepted.)
8 The alloying process helps to alter the properties of a pure metal to make it harder and stronger because in this process the foreign atoms that are mixed with the pure metal make flag bookmark A the arrangement of the pure metal atoms more orderly B the bonds between the pure metal atoms stronger C the layers of pure metal atoms more difficult to slide D the bonds between the pure metal atoms and the foreign metal atoms stronger T4 Chapter 8.1 Alloy and Its Importance The foreign atoms have a different size, so they disrupt the orderly layers of the pure metal. The layers can no longer slide over each other easily, so the alloy is harder and stronger.
9 Which of the following are oxidising agents? I Potassium iodide II Iron(II) sulphate III Iron(III) chloride IV Acidified hydrogen peroxide flag bookmark A I and II B I and IV C II and III D III and IV T5 Chapter 1.1 Oxidation and Reduction Oxidising agents accept electrons. Iron(III) chloride ($\text{Fe}^{3+} + e^- \rightarrow \text{Fe}^{2+}$) and acidified hydrogen peroxide are oxidising agents. Potassium iodide and iron(II) sulphate donate electrons, so they are reducing agents.
10 Which of the following is the correct match? | | Homologous series | General formula | Name of functional group | |---|---|---|---| | A | Alkane | $\text{C}_n\text{H}_{2n+1}$, n = 1, 2, … | Single bond | | B | Alkene | $\text{C}_n\text{H}_{2n}$, n = 2, 3, … | Double bond | | C | Alcohol | $\text{C}_n\text{H}_{2n+1}\text{COOH}$, n = 0, 1, 2, … | Carboxyl | | D | Carboxylic acid | $\text{C}_n\text{H}_{2n+1}\text{OH}$, n = 1, 2, … | Hydroxyl | flag bookmark A A B B C C D D T5 Chapter 2.2 Homologous Series Alkenes have the general formula $\text{C}_n\text{H}_{2n}$ (n = 2, 3, …) and the functional group is the carbon–carbon double bond. Alkanes are $\text{C}_n\text{H}_{2n+2}$, and the formulas and functional groups of alcohols and carboxylic acids are swapped in C and D.