YEAR 8 CHEMISTRY END SEMESTER 1 EXAM 1. Pierre heats some black coffee sweetened with sugar, using this apparatus. The coffee boils (a) A liquid collects in the test tube standing in the beaker.(2) What is the name of the liquid? Tick (√) the correct box. (b) Why is the test tube that collects the liquid standing in a beaker of cold water? (2) 2. The diagrams show the arrangement of particles in solids, liquids and gases. (a) Draw lines to match each word with the correct diagram.(3)
(b) The table shows some properties of a solid, liquid and gas.(3) Tick (√) the box to show if the property is of a solid, liquid or gas. (c) Explain using particle theory how a liquid change to gas. (5) 2.The elements in the periodic table have different chemical symbols.(5) Write the chemical symbols of the following elements Aluminium Argon Potassium Calcium Carbon 3. Zoran has an unknown element. He wants to know if it is a metal or a non-metal. Zoran writes down his results.
(a) Do you think this element is a metal or a non-metal? (1) Which one piece of evidence in Zoran’s results made you decide this? (2) (b) Describe two other differences between metals and non-metals. (2) 4.Chemicals can be elements or compounds. (a)Tick (√) the box to show which chemicals are elements and which chemicals are compounds. The first one has been done for you.(4) (b)i)Write the chemical formulae of sodium hydroxide.(1) ii)What elements is sodium hydroxide made of.(3)
iii)Name the types of atoms and their numbers in sodium hydroxide.(6) 5. Hydrochloric acid produces a gas. So does ammonia solution. These two gases react when they meet to form a white solid called ammonium chloride. Some cotton wool soaked in hydrochloric acid was placed at one end of a glass tube. Some cotton wool soaked in ammonia solution was placed at the other end. The diagram shows what happened. (a) What is the name of the process by which the gases move along the tube? (1) (b) Explain how this process takes place. (3) (c) The particles of hydrochloric acid have a greater mass than the particles of ammonia. Suggest why the ammonium chloride is formed nearer to the hydrochloric acid end of the tube than the ammonia solution end. (2) (d) Define diffusion. (2) 6.When there is an unpleasant smell in a room, what can you do to get rid of it? Explain why this works, in terms of particle theory. (4)