1 Which of the following atomic models was presented by Niels Bohr? flag bookmark A B C D T4 Chapter 2.2 The Development of the Atomic Model Niels Bohr's model has a nucleus of protons with electrons moving in fixed shells around it (C). A is Thomson's model, B is Rutherford's model with no shells, and D, with neutrons in the nucleus, is Chadwick's model.
2 A cancer patient needs to undergo radiotherapy treatment to kill cancer cells. What is the substance used in the radiotherapy equipment? flag bookmark A Iodine-131 B Cobalt-60 C Sodium-24 D Carbon-14 T4 Chapter 2.4 Isotopes and Its Uses Cobalt-60 gives out gamma rays, which are used in radiotherapy to kill cancer cells. Iodine-131 treats thyroid problems, sodium-24 detects blood clots, and carbon-14 is used for dating.
3 Which of the following is the correct formula of an ion? flag bookmark A $\text{Ag}^{2+}$ B $\text{Ag}^{3+}$ C $\text{Al}^{2+}$ D $\text{Al}^{3+}$ T4 Chapter 3.3 Chemical Formula Aluminium (2.8.3) loses its 3 valence electrons to form $\text{Al}^{3+}$. Silver forms $\text{Ag}^+$, not $\text{Ag}^{2+}$ or $\text{Ag}^{3+}$.
4 Which of the following substances is equal to 1 mol? [Avogadro constant = $6.02 \times 10^{23}$; Relative atomic mass: Mg = 24, Cl = 35.5; Molar volume of gas at room conditions = 24 dm³ mol⁻¹] flag bookmark A Magnesium chloride with a mass of 59.5 g B Zinc chloride containing $6.02 \times 10^{24}$ formula units C Silicon dioxide containing $6.02 \times 10^{23}$ molecules D Carbon dioxide with a volume of 2400 cm³ at room conditions T4 Chapter 3.2 Mole Concept $6.02 \times 10^{23}$ particles is exactly 1 mol (C). (Strictly, silicon dioxide is a giant covalent structure, so its particles are formula units rather than molecules, but C is the intended answer.) A: $\text{MgCl}_2$ = 95 g mol⁻¹, so 59.5 g is 0.63 mol. B: $6.02 \times 10^{24}$ is 10 mol. D: 2400 cm³ = 2.4 dm³ = 0.1 mol.
5 Which characteristics are correct about elements in Group 1 of the Periodic Table going down the group? I The tendency to donate electrons increases II The hardness of the metal increases III Heat conductivity decreases IV The melting point decreases flag bookmark A I and III B I and IV C II and III D II and IV T4 Chapter 4.4 Elements in Group 1 Going down Group 1 the atoms get bigger, so the valence electron is held less strongly and is donated more easily (I). The metallic bonds get weaker, so the metals become softer and their melting points decrease (IV).
6 Diagram 1 shows the formation of ammonia boron trifluoride when ammonia, $\text{NH}_3$ reacts with boron trifluoride, $\text{BF}_3$. What type of bond is formed? flag bookmark A Dative bond B Ionic bond C Covalent bond D Hydrogen bond T4 Chapter 5.5 Dative Bond The nitrogen atom of ammonia gives its lone pair of electrons to the boron atom, which has an empty orbital. Both shared electrons come from nitrogen, so the bond is a dative bond.
7 Which of the following is the correct term for a chemical substance that ionises partially in water to produce a low concentration of hydroxide ions? flag bookmark A Strong acid B Weak acid C Strong alkali D Weak alkali T4 Chapter 6.3 Strength of Acids and Alkalis A substance that produces hydroxide ions is an alkali. If it ionises only partially and gives a low concentration of $\text{OH}^-$ ions, it is a weak alkali, for example aqueous ammonia.
8 Which of the following statements is correct about a catalyst? flag bookmark A A catalyst can increase the quantity of product formed B A catalyst does not change its physical state after the reaction C A catalyst increases the activation energy of a reaction D Only a small amount of catalyst is required to speed up a reaction T4 Chapter 7.2 Factors Affecting Rate of Reactions Only a small amount of catalyst is needed because it is not used up. A catalyst does not change the quantity of product, it lowers (not raises) the activation energy, and its physical state may change (e.g. a lump may become powder) even though it is chemically unchanged.
9 Photochromic glass is a composite material that is used in the manufacture of car windows and building windows. Which of the following are the substances added to glass to make photochromic glass? I Copper(I) chloride II Iron(II) chloride III Silver chloride IV Barium chloride 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 Photochromic glass contains silver chloride (III) with a little copper(I) chloride (I). In bright light silver chloride darkens the glass, and copper(I) chloride helps it turn clear again in dim light.
10 Diagram 2 shows a pressure cooker. Which of the following glass is used in part X? flag bookmark A Borosilicate glass B Lead crystal glass C Soda-lime glass D Fused silica glass T4 Chapter 8.2 Composition of Glass and Its Uses Part X is the glass lid, which gets hot and is heated and cooled again and again. Borosilicate glass has a low coefficient of expansion and resists heat, so it does not crack easily.