10.1 The experimental set-up below is used in a Grade 10 class to demonstrate the electrical conductivity of a sodium chloride solution. 10.1.1 Define the term electrolyte. (2) 10.1.2 Write down the formula of ions present in this set-up. (1) 10.1.3 What will happen to the brightness of the bulb in the set-up above if … Read more
A hydrous salt is composed of anions and cations which are surrounded by a weaklybonded water molecule. Each hydrous salt has a fixed number of water moleculesassociated with it. When a salt holds a water molecule, we call it a hydrated orhydrous salt. 9.1 Write down the term that best describes the water molecule that … Read more
8.1 Consider the diagram below that shows liquid water evaporating to form water vapour. Use chemical formulae to represent the process in the diagram above and indicate the phases of the substance undergoing this process. (2) 8.2 Give THREE separation methods that can be used to reverse a physical change. (3) 8.3 Two Grade 10 … Read more
Study the illustrations of the diagrams below and answer the questions which follow. 7.1 Define the term compound. (2) 7.2 Choose from the different diagram illustrations above ONE that best describes each of the following substances. Write down the letter only. 7.2.1 Diamond (1) 7.2.2 Carbon dioxide (1) 7.2.3 Helium (1) 7.2.4 Magnesium (1) 7.2.5 … Read more
6.1 Methane gas is one of the hydrocarbons that is used as a source of fuels worldwide. When methane reacts with oxygen, water and carbon dioxide are formed. Atoms of water molecules in the above reaction are bonded by a covalent bond. 6.1.1 Define the term covalent bond. (2) 6.1.2 Write down the balanced chemical … Read more
Study the following table of elements with the first ionisation energy values inkJ.mol-1 and answer the questions that follow. 5.1 Define the term ionisation energy. (2) 5.2 A certain element in the table above is in group II of the periodic table. 5.2.1 Write down: (a) The CHEMICAL NAME of this element (1) (b) The … Read more
Below is the Aufbau diagram of an unknown atom. Study the diagram and answerthe following questions. 4.1 Define the term atomic number. (1) Use the Aufbau diagram of an unknown atom above to answer the followingquestions. 4.2 In which group and period is the atom in the diagram above? (2) 4.3 4.4 How will the … Read more
The following diagram, not drawn to scale, represents the heating curve for a certain substance. Point A represents t = 0 minutes where the substance is a solid. 3.1 Define the term melting point. (2) Use the information in the diagram to answer the following questions 3.2 Write down: 3.2.1 Between which two letters is … Read more
2.1 Define the term element. (2) 2.2 Use the diagram and key provided to answer the following questions. 2.3 Write down the letter of the diagram that represents: 2.3.1 A substance that is solid at room temperature (1) 2.3.2 A mixture that is non-uniform (1) 2.3.3 A pure substance consisting of two or more different … Read more
Four options are provided as possible answers to the following questions. Choose the answer and write only the letter (A–D) next to the question numbers (1.1–1.10) in the ANSWER BOOK, for example 1.11 E. 1.1 Which ONE of the following is a good conductor of electricity? A Wood B Plastic C Silicon D Copper (2) … Read more