1 Which element exists as molecules at room temperature? flag bookmark A Water B Carbon C Oxygen gas D Sodium chloride T4 Chapter 2.1 Basic Concepts of Matter Oxygen is an element made of O₂ molecules. Water and sodium chloride are compounds, not elements, and carbon exists as a giant structure of atoms.
2 Which of the following statements is true about helium? flag bookmark A Exists as diatomic molecules B Does not dissolve in water C High melting and boiling points D Has an octet electron arrangement T4 Chapter 4.3 Elements in Group 18 Helium is a noble gas: it exists as single atoms, does not dissolve in water and has very low melting and boiling points. It has a stable duplet (2), not an octet.
3 The table shows the pH values of four alkali solutions that have the same concentration. | Solution | U | V | W | X | |---|---|---|---|---| | pH | 9 | 10 | 12 | 14 | Which alkali solution has the highest degree of ionisation? flag bookmark A U B V C W D X T4 Chapter 6.3 Strength of Acids and Alkalis At the same concentration, the alkali with the highest pH produces the most hydroxide ions, so it ionises the most. X has pH 14.
4 Which unit is used for the rate of reaction? flag bookmark A g mol^-1 B g min^-1 C mol dm^-3 D kJ mol^-1 T4 Chapter 7.1 Determining Rate of Reaction Rate of reaction is the change in quantity per unit time, for example the mass of a substance in grams per minute, g min⁻¹.
5 Which of the following is a composite material? flag bookmark A Photochromic glass B Lead crystal glass C Borosilicate glass D Soda-lime glass T4 Chapter 8.4 Composite Materials and Its Importance Photochromic glass is a composite material: glass combined with silver chloride and copper(I) chloride. The other three are ordinary types of glass.
6 Which set of definitions of reduction in terms of oxygen, hydrogen and electrons is correct? flag bookmark A Oxygen: Gain; Hydrogen: Loss; Electrons: Loss B Oxygen: Gain; Hydrogen: Loss; Electrons: Gain C Oxygen: Loss; Hydrogen: Gain; Electrons: Gain D Oxygen: Loss; Hydrogen: Gain; Electrons: Loss T5 Chapter 1.1 Oxidation and Reduction Reduction is the loss of oxygen, the gain of hydrogen and the gain of electrons.
7 An example of an endothermic reaction is flag bookmark A respiration B photosynthesis C rusting of iron T5 Chapter 3.1 Heat Change in Reactions Photosynthesis absorbs light energy from the surroundings, so it is endothermic. Respiration and rusting release heat.
8 Substance R is one of the synthetic polymers used in daily life. Substance R is also used for making toys. What is substance R? flag bookmark A Teflon B Nomex C Nylon D Kevlar T5 Chapter 4.1 Polymer Nylon is a synthetic polymer used to make clothing fabric like the T-shirt shown, and also toys. Teflon, Nomex and Kevlar have more specialised uses.
9 The diagram shows a type of plant used in traditional medicine. Which of the following is a use of the plant? flag bookmark A Treats ringworm B Prevents flu C Lowers blood pressure D Relieves burn wounds T5 Chapter 5.4 Medicines and Cosmetics The plant is aloe vera. Its gel is used in traditional medicine to soothe and heal burns.
10 Which unit is correct for molar volume? flag bookmark A g mol^-2 B g mol^-3 C dm^3 mol^-2 D dm^3 mol^-1 T4 Chapter 3.2 Mole Concept Molar volume is the volume occupied by one mole of gas, so its unit is dm³ mol⁻¹.