2020 NOVEMBER EXAM PAPER GR7 NS hlayiso.com

Downloaded to.//. 2o?o from hlayiso.com z't<*l=l S- = U Natural Science ffi End-of-year Exam ination Properties of Materials; Separating Mixtures; Acids, Bases and Neutrals; Periodic Table of Elements; Potential and Kinetic Energy; Heat Transfer; lnsulation and Energy Saving Examiner: Ms K Barnard Total Marks: 80 Moderator: Ms G Botes Time: 90 Minutes Learner: Grade 7. : 4&- 1 4rr^ 2 4ir- ^? LEARNER MARK ANALYSIS SECTIONS LEVEL: LEARNER'S MARK Section A Question 1 t6 Q-29o/o Question 2 t5 30-39% 2 Question 3 t6 4A-49o/o 3 Section B 50-59% 4 Question 4 t23 60-69% 5 80 Question 5 t18 7A-79o/o j 6 Question 6 t22 80-100% 7 lnstructions: o This paper consists of 6 questions. .. Answerg![ the questions in the spaces provided on the answer sheet. o Write neatly and legibly and answer your questions in blue pen ONLY. o Good luckl ffi

Downloaded from hlayiso.com SECTION A QUESTION 1: Multi ple c hoi ce question s Choose the correct answer from the following guesfions and only write the correct letter next to the question number on your answer sheef. 1.1 Materials that allow electricity to move through them. (1) a. Flexibitity b. Electrical conductors c. Materials d. Electrical insulators 1.2 When you use a magnet to separate a mixture. (1) a. Magnetism b. Evaporation c. Sieving d. Distillation 1.3 This word is used to describe a substance that eats through clothing, stonework and metals, and can burn the skin. (1) a. Bases b. Acids c. Sour d. Corroslve 1.4 The temperature at which a liquid turns into a gas. (1) a. Electrical Conductor . b. Tensile Strength c. Boiling Point d. Melting Point 1.5 This substance is neither acid nor base and is not dangerous. (1) a. Neutral b. Base c. Acid d. Caustic 1.6 Two or more substances with different properties that are mixed together. (1) a. Mixture b. Semi-metal c. Pure Substance d. Acid Question 1: /6

Downloaded from hlayiso.com QUESTION 2: Column A and B Fit the correct term in column A to the definition in column B. Only write the canect letter on your answer sheet. Column A Column B 2.1 Kinetic Energy A The transfer of heat between solid objects. 2.2 Conduction B Energy that an object has because it is moving. 2.3 Convection c Materials that reduce heat loss. The way that heat energy flows through liquids and 2.4 Potential Energy D gases. 2.5 lnsulating materials E Energy stored in an object or system. Question 2: l5 QUESTION 3: . Terminology 3.1 Give the word for the fottowing definitions: 3.1.1 Substances that transfer heat easily (1) 3.1.2 Factors that can change within an experiment (1) ' 3.1 .3 Substances that do not transfer heat easily (1) 3.2 Glve the definition of the foltowing words: 3.2.1Vacuum (1) 3.2.2 \Narm-blooded (1 ) 3.2.3 Solar power (1) Question 3: 16 SECTION A: [17]

Downloaded from hlayiso.com SECTION B QUESTION 4: Case Sfudies 4.1 Read the following case study and then answer the questions that follow: Water Reservoirs Water reservoirs are built to provide water for towns. They are built uphillfrom the houses in a town. ln this way, the stored water has enough potential energy to flow when a tap in the town is opened. The height of the reservoir determines how strongly the water will flow from the taps. \Mren the water reservoir is not much higher than the houses, the water only trickles out of the taps. Water in reservoirs that are positioned lower than the houses, or water from boreholes and wells, have to be pumped up to the houses. This is because the water below the level of the houses does not have enough energy to reach the houses. 4.1.1 Give the definition of potential energy. (1) 4.1.2 What are the three types of potential energy? (3) 4.1.3 What type of potential energy is in a water reservoir? (1) 4.1.4 Rainwater naturally flows downhill because of gravity. However, dams are built in valleys downstream. Explain how the water gets from the dam (downstream) to the town (upstream). (1) 4.1.5 Answer TRUE or FALSE to the following questions: a. Kinetic energy is energy that an object has because it is moving. (1) b. A group of parts that work together to do a specific task is called potential energy. (1) c. Energy is transferred when ditferent parts of a system react and cause change. (1) 4.1.6 Describe the law of conservation of energy. (4) [13]

Downloaded from hlayiso.com 4.2 Read the following case study and then answer the questions that follow: Mushroom ln'sulation ln 2009, two mechanicalengineering students- Gavin Mclntyre and Eben Bayer, became the fathers of Greensulate, an insulator used in sustainable housing. They started out by growing mushrooms under their beds! After many experiments, they patented their unique biomaterial- material made from living organisms'. Starch is obtained from by-products collected from farms, such as rice hulls and buckwheat husks. These are mixed with water and hydrogen peroxide, and poured into a mould. Cells from the oyster mushroom grow into a network that looks like fibres. GroMh takes place in the dark at room temperature. The only disadvantage of this process is that it takes about two weeks to grow, thereafter, the mesh is dried and ready for use. Greensulate traps more heat than newspaper or fibreglass and is fire-resistant. lt is biodegradable and much cheaperto produce than insulators such as Styrofoam and plastic. This makes it an environmentally frien dly a ltem ative for insu lation. 4.2.1\Alhat organism did the two men use to make the insulation. (1) 4.2.2Vlhat is the difference between a heat conductor and an insulator? (2) 4.2.3The word'biomaterial' has been used in the text. What does this word mean? (1) 4.2.4Which environment do the oyster mushrooms need to be able to grow? (2) 4.2.5 List three other insulators that have been mentioned in this article. (3) 4.2.6 List one disadvantage in the production of Greensulate. (1) [1 0l Question 4: 123

Downloaded from hlayiso.com QUESTION 5: Translations 5.1 Heat conduction Make use of the following information to answer the questions that follow. Conductivitv of metals: ln order to find out which metal has the highest conduction of heat, a group of grade 7 leamers conducted the following experiment: They collected rods of the same length of four types of metals. One end of the rod was placed nearest to the Bunsen burner and the other si$e of the metal rods were placed on a tripod stand. Vaseline was placed at the end of each rod. The question they wanted to answer was, "Which metalhas the highest conduction of heat?" After setting up the experiment, they turned on the bumer and started their stopwatches in order to time how long it took for the Vaseline to melt on each of the metal rods. They carefully recorded their results as follows: Type of metal Aluminium Steel Coppe lron Time taken 12 seconds 20 seconds 10 seconds 15 seconds 5.1 .1 Draw a bar graph to show the results of the experiment. (8) 5.1.2 What conclusion can be drawn after the results have been obtained? (Which metal has the highest conductivity of heat and which material has the lowest conductivity of heat?) (2) 5.1.3 ldentify the variables in the experiment. a. The rndependent variable: (1) b. The dependent variable: (1) [12)

Downloaded from hlayiso.com 5. 2 Energy flow.diagrams Make use of the following information on the sysfem of a water wheel to formulate an energy flow diagram. An energy flow diagram is a visual way to show energy transfer in different parts of an energy sysfem. lt shows energy transfer in three stages: - The input sfage - The process sfage - The outpuf sfage The svstem of a water wheel: i A water wheel is a machine for converting the energy of flowing i or falling water (gravitational potential energy) into useful forms i of power. The gravitational potential energy is turned into kinetic )i energy i : bythedownwardsforceofthefallingwaterwhichmakesitturn. This turning motion produces energy. i i 5.2.1 Draw an energy flow diagram that describes the workings of a water wheel. (6) INPUT: PROCESS: OUTPUT: Question: Question: Question: Process: Process: Process: t6l Question 5: 118

Downloaded from hlayiso.com QUESTION 6: lnvestigations 6.1 lnvestigate the most efficient way to separate mixtures. Make use of the following table to work out the best way to separate the mixtures that follow. Write down the separation technique as wellas a reason for using the separation technique. Method Hand-sortino Sievino Filtration Maonetism Evaporation Solids of Magnetic Solids of different sizes Type of lnsoluble solids substances from Soluble solid different sizes, wherein one substance from liquids non-magnetic and liquid colours, textures solid is quite substances small What would the best separation techniques be to separate the following mixtures (Give a reason for your answer): 6.1.1 lron fillings and sand (2) 6.1.2 Salt and water (2) 6.1.3 Building sand and stones (2) 6.1.4 Buttons and coins (2) t8l

Downloaded from hlayiso.com 6.2 lnvestigate the workings of litmus paper as an acid-base indicator. The acid-base indicator investigation A group of grade 7 learners conducted an experiment with litmus paper to test wtrich colour changes happen on specific substances. Four household objects were tested using litmus paper. The following results were obtained: Vinegar: BLUE litmus paperturned RED Toothpaste: RED litmus paperturned BLUE Lemon: BLUE litmus papertumed RED Bicarb of soda: litmus tumed 6.2.1 Fill in the correct words: Acids taste a. and feel b. , while bases taste c. and feel d. (2) 6.2.2 By looking at the results of this investigation we can see whether the household objects are acidic or basic, lndicate whether the following household objects are acidic or basic based off the colour change of the litmus paper: a. Vinegar (1) b. Lemon (1) c. Toothpaste (1) d. Bicarb of soda (1) t6l

Downloaded from hlayiso.com 6.3. The Periodic Table of Elements 6.3.1 Categoise the following properties of metals and non-metals into the correct column. The first answer has been done as an example. Good conductors Low melting point Shiny, ductile, malleable Poor conductors High melting point Dull, non-ductile and brittle METALS NON.METALS E.s. Hish Meltins Point E.g. Low Melting Point (4) 6.3.2 Look at the following elements and use the periodic table provided to indicate where on the periodic table they are located. 9 12 I 20 r Mg 2430 Hl.oo Cq 40.o8 (a) (b) (c) (d) (4) P1 The Periodic Table of Elements P2 P3 6910tt12 l8 t/- . ---\ t Vlll ll8 I - . !8 , 2E P4 P5 /E., P6 Pt q?lrl,Ir P7 SECTION B: {521