1 CHAPTER 1 Microorganisms Brain Teaser (pg. 6) Mucor on bread can be seen with the naked eye as it is made up of a colony of mucor. Brain Teaser (pg. 9) The bottom of the ocean is a dark place. Due to the absence of light, algae cannot live at the bottom of the ocean as they are unable to make their own food through photosynthesis. Brain Teaser (pg. 12) Spherical Brain Teaser (pg. 16) Water is boiled to ensure all microorganisms including Vibrio cholerae which causes cholera are killed. Experiment 1.1 (pgs. 17 – 18) Questions (pg. 18) 1. To kill the bacteria in the nutrient agar and Petri dishes. 2. (a) To prevent other microorganisms from entering. (b) To prevent condensed water from dripping onto the surface of the nutrient agar which will affect the growth of bacteria on the surface of the agar. (c) To keep out light especially sunlight which retards the growth of bacteria. 3. (a) Petri dish A. Unwashed fingers have the highest number of bacteria. (b) Petri dish C. Fingers which have been washed with soap and water have the lowest number of bacteria. 4. Functions as a control to compare results of the experiment. 5. No, because the nutrient agar has been sterilised and sealed to prevent other microorganisms from entering. Experiment 1.2 (pgs. 20 – 27) A. Questions (pg. 22) 1. The larger the number of bacterial colonies, the higher the rate of growth of bacteria. 2. The nutrient agar is the source of food for bacteria. B. Question (pg. 23) To avoid killing the Bacillus sp. with heat from the hot nutrient agar C. Question (pg. 24) Heat from sunlight will kill Bacillus sp. and affect the result of the experiment. D. Question (pg. 25) To show that high temperature is not suitable for the growth of bacteria E. Question (pg. 27) Use of toothpaste to brush teeth. Toothpaste has a high pH value. The high pH value retards or kills various types of microorganisms including bacteria. Formative Practice 1.1 (pg. 27) 1 Microorganisms are minute organisms which cannot be seen with the naked eye. 2. (a) Fungi, algae, protozoa, bacteria, viruses (b) Size, shape, method of reproduction, nutrition, habitat 3. Fungi, bacteria 4. Deoxyribonucleic acid (DNA)/ribonucleic acid (RNA) and protein layer (capsid) 5. Nutrition, humidity, light, temperature, pH value 6. (a) Protozoa (b) (i) Pseudopodium (ii) To move and engulf food Formative Practice 1.2 (pg. 32) 1. (a) Recombinant DNA of E. coli, Penicillium chrysogenum ANSWERS KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 1 10/28/20 12:26 PM
2 (b) Bifidobacteria sp., Nitrosomonas sp., Nitrobacter sp. (c) Yeast, Lactobacillus bulgaricus, Bifidobacteria sp. 2. Example of food Microorganism used Bread Yeast Yoghurt Lactobacillus bulgaricus 3. (a) Eco enzyme is a natural product from agricultural waste such as fruit or vegetable waste processed through fermentation. (b) • Treats wastewater and sewage • Minimises agricultural waste such as fruit and vegetable waste • As a cleaning solution (any two) 4. (a) Lactobacillus sp. (b) • Eliminates foul odour • Facilitates animal digestion • Produces enzyme • Treats sewage • Makes compost • Advances the fishing industry (any three) Experiment 1.3 (pgs. 37 – 39) Questions (pg. 39) 1. As a control 2. The clear region on the surface of the nutrient agar is the region without bacteria or where bacterial growth is inhibited. Therefore, the clear region formed around the disc containing penicillin shows the action of penicillin which inhibits the growth of bacteria or kills bacteria. 3. The clear region around the filter paper disc containing more concentrated penicillin is larger or wider than the clear regions around the other filter paper discs containing less concentrated penicillin. This shows that the higher the concentration of penicillin, the lower the growth of bacteria. Brain Teaser (pg. 41) Superbugs are bacteria which can no longer be killed or are resistant to existing antibiotics. Superbugs may be prevented by using new and more effective antibiotics. Brain Teaser (pg. 41) A vaccine contains antigens obtained from a part or the whole structure of a weakened or dead virus that are incapable of causing infections. Theses antigens stimulate the human body’s immune system by developing immunity against certain infections caused by the virus. This in turn prevents infections caused by the virus. An antiviral is a type of medicine that does not kill or destroy a specific type of virus but prevents the development or reproduction of that specific type of virus. Formative Practice 1.3 (pg. 41) 1. • Sterilisation • Boiling • Using antiseptic • Disinfecting • Radiation 2. The aseptic technique is applied to protect a person from infections by eliminating existing or nearby pathogens before the person contracts any diseases caused by the pathogens. 3. (a) Sterilisation is the process of killing or eliminating microorganisms from an object or a particular surrounding. (b) Sterilisation is carried out using heat, chemical substances, radiation, high pressure and filtration. (c) The temperature in the autoclave (121°C – 132°C) can kill microorganisms and their spores. Water boiled at 100°C can only kill microorganisms but not their spores. This is because their spores can withstand a temperature of 100°C. 4. Similarity: Both antiseptics and disinfectants can be used to kill pathogens. Difference: Antiseptics can be applied on the skin of humans but disinfectants are not suitable to be applied on the human skin. 5. Ultraviolet ray, X-ray, gamma ray KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 2 10/28/20 12:26 PM
3 6. (a) Athlete’s foot: antifungal (b) Pneumonia: antibiotic (c) Shingles: antiviral Summative Practice 1 (pgs. 43 – 45) 1. (a) The higher the concentration of the antibiotic, the larger the area of the clear region. (b) (i) Type of bacteria, surrounding temperature (ii) Concentration of antibiotic (c) Antibiotics can kill bacteria. 2. (a) Have cell wall and cell membrane Have no cell wall and cell membrane P, Q, R, T S (b) Virus (c) (i) Yeast (ii) Microorganism P is a useful microorganism because it is used to make food such as bread. Microorganism P is not a pathogen because it does not cause disease. 3. (a) Cloudy (b) The optimum temperature for growth of bacteria is 37°C. (c) (i) Temperature (ii) Condition of nutrient broth after 3 days (d) The nutrient broth is cloudy at 37°C because 37°C is the optimum temperature for bacterial growth. 4. Apparatus set-up X Method 1: Observe and compare the volume of carbon dioxide collected in the balloon. 20°C 30°C 40°C 50°C Apparatus set-up Y Method 2: Observe and compare the thickness of the layer of carbon dioxide foam, X, on the surface of the mixture of yeast and sugar solution. Thickness of foam layer (mm) 10 X 12 8 6 4 2 0 20 30 40 50 Temperature (ºC) Method 3: Observe and count the number of gas bubbles released in the test tube per minute. Method 4: Observe and measure the time taken for the limewater to turn cloudy. Apparatus set-up Z Method 5: Measure the volume of carbon dioxide in the syringe after an hour. Volume of carbon dioxide KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 3 10/28/20 12:26 PM
4 Volume of carbon dioxide collected after 1 hour (cm3 ) 80 60 40 20 20 30 40 50 0 Temperature (ºC) CHAPTER 2 Nutrition and Food Technology Experiment 2.1 (pgs. 51 – 53) Questions (pg. 53) 1. (a) Smaller (b) The difference in the calorific value is due to a portion of the energy lost to the surroundings as heat energy. 2. (a) Rice (b) Palm oil (c) Egg white 3. Water. This is because water cannot be completely oxidised or burnt. Brain Teaser (pg. 55) Restaurants that operate 24 hours a day encourage late-night eating. Eating unhealthy food that exceeds body requirements, especially late at night will cause weight gain, risk of obesity and disruption of sleep. Formative Practice 2.1 (pg. 56) 1. (a) The concept of Pinggan Sihat Malaysia means a quarter of the plate is filled with carbohydrate sources, another quarter of the plate is filled with protein sources and half the plate is filled with fruits and vegetables. (b) The concept of Pinggan Sihat Malaysia helps in the consumption of balanced nutrition to prevent obesity which can cause various noninfectious diseases such as diabetes. 2. (a) The calorific value (or energy value) of a food is the amount of energy released from the complete oxidation or burning of 1 g of the food. (b) Bomb calorimeter (c) Calorific value of food sample = 4.2 J g–1 °C–1 × Mass of water (g) × Change in temperature of water (°C) Mass of food sample (g) × 1 000 3. (a) Reduction in body weight (b) Excessive body weight or obesity 4. (a) Inappropriate mealtimes (b) Food servings that do not follow balanced nutrition and calorific requirements. Experiment 2.2 (pgs. 60 – 61) Questions (pg. 61) 1. To block light from entering the culture solution in the boiling tubes. Culture solution exposed to light encourages growth of algae. Algae will absorb nutrients from the culture solution and affect the results of the experiment. 2. Aerating the culture solutions supplies oxygen for the respiration of the roots. 3. To replace the macronutrients which have been absorbed by the seedlings. 4. Surrounding temperature, humidity of air, light intensity (any one) Formative Practice 2.2 (pg. 61) 1. (a) • Macronutrient is an element (or mineral) needed by plants in large quantities. • Carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium and sulphur (any five) (b) • Micronutrient is an element (or mineral) needed by plants in small quantities. • Boron, molybdenum, zinc, manganese, copper and iron (any five) 2. Plants need macronutrients and micronutrients for healthy growth, development and reproduction. KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 4 10/28/20 12:26 PM
5 3. (a) Stunted growth of roots (b) Brown spots on edges of leaves (c) Small leaves which fall easily Formative Practice 2.3 (pg. 65) 1. Nitrogen cycle is a natural cycle that recycles nitrogen between plants and animals, and the atmosphere, soil and water. 2. (a) Lightning or volcanic eruptions, nitrogen fixation, nitrification (b) Absorption of nitrate ions from the soil, denitrification, nitrate leaching 3. Nitrogen-fixing bacteria in the nodules of legume plants use nitrogen from the air to form nitrate ions through nitrogen fixation. Therefore, the fertility of the soil is increased through the addition of nitrate ions to the soil. 4. During rainy season, the content of nitrate ions in the soil usually decreases. Nitrate ions in the soil dissolve in rainwater and flow out from the soil into rivers, underground water or the sea. Formative Practice 2.4 (pg. 75) 1. Rapid growth and maturing, resistance to disease, pest and extreme weather, easier and less cost to care for, and high yields of higher quality 2. Cloning, cross-breeding, genetic engineering, genetic mutation technology 3. FAMA 4. Crop rotation, mixed planting and terrace farming 5. Biological control is a method which applies interaction between organisms such as prey-predator and parasitism to control crop pests in a habitat. Formative Practice 2.5 (pg. 82) 1. Food processing is a way of changing raw food substances in the natural form to food substances in another form. 2. Purposes of processing food are as follows: • so that it is edible • lasts longer • tastes better • more nutritious • more attractive (any four) 3. Cooking, fermentation, dehydration/ drying, pasteurisation, canning, freezing, irradiation, vacuum packaging (any four) 4. (a) Colouring (b) Stabiliser (c) Bleach 5. To bleach the original colour of palm oil. 6. (a) Vacuum packaging (b) Salted fish, shrimp paste (belacan) (c) To prevent the strong smell of the food from being released into the air Brain Teaser (pg. 83) • Iron • Iron is an important component of haemoglobin in red blood cells. Brain Teaser (pg. 85) New processing technologies and chemical substances always produce new types of food. Formative Practice 2.6 (pg. 86) 1. Health food is natural food in a normal diet which maintains health and does not contain chemical substances usually used in food processing . Example: orange, tomato, ginger 2. Health supplement is nutrient taken in the form of capsule, pill, liquid and powder in specific dosages. Example: vitamin C, protein powder 3. Ministry of Health Malaysia 4. Food Act 1983 Summative Practice 2 (pgs. 88 – 89) 1. (a) Consumption of whale meat can warm the body compared to other food. (b) (i) Aim of experiment To measure and compare the calorific values of fat, carbohydrate and protein KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 5 10/28/20 12:26 PM
6 (ii) Identification of variables • Manipulated variable: Type of food sample • Responding variable: Rise in temperature • Constant variable: Mass of water in calorimeter (iii) List of materials and apparatus • Materials: Fat, carbohydrate and protein samples weighing 1 g each, distilled water and cotton wool • Apparatus: Retort stand, boiling tube, thermometer, shield, plasticine and needle (iv) Procedure or method 1. Prepare the apparatus set-up shown in the figure below. Boiling tube Distilled water Food sample Needle Plasticine Thermometer Cotton wool Retort stand 2. Record in a table the type of food sample and its mass, mass of water in the calorimeter, and initial temperature, T1 on the thermometer. 3. Use a lighter to light up the food sample. 4. Observe and record the final temperature, T2, after the food sample has completely burned. (v) Tabulation of data Type of food sample Temperature change (°C) 2. (a) Average daily energy requirement (kJ) 15 000 10 000 5 000 0 10 20 30 40 Age (year) x x x x x x x x (b) 8 500 kJ (c) Average daily energy requirement decreases with age 3. (a) (i) Put several pieces of cempedak in a plastic bag. (ii) Connect a bicycle pump to the opening of the plastic bag. Use the bicycle pump as a vacuum pump to remove air from the plastic bag. (iii) Seal the opening of the plastic bag by using a sealing machine. (b) When the piston of the bicycle pump is pulled, air is sucked into the bicycle pump. The bicycle pump functions as a vacuum pump. (c) The effectiveness of the vacuum packaging is evaluated based on the following characteristics: • no smell of the cempedak is detected • no air is trapped in the plastic bag containing the cempedak KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 6 10/28/20 12:26 PM
7 CHAPTER 3 Sustainability of the Environment Formative Practice 3.1 (pg. 99) 1. Carbon footprint usually refers to the total carbon dioxide released to the atmosphere as a result of activities of individuals, events, organisations, communities or products used in daily life. 2. Use of electrical energy, water, transport, food, waste, release of greenhouse gases and frequency of use of the product 3. • Carbon footprint of a product refers to the negative impacts to the sustainability of the environment caused by the product throughout its life cycle. • Carbon handprint of a product refers to the positive impacts to the sustainability of the environment caused by the product throughout its life cycle. 4. • Life cycle of a product which starts from source to disposal stage and then recycled (cradle-to-cradle life cycle of a product). • Life cycle of a product which starts from source to disposal stage and then allowed to rot (cradle-to-grave life cycle of a product). 5. Upcycle is a recycling process to produce new products of higher value than the original product. 6. Microplastic is a plastic piece measuring less than 5 mm in length. It is hazardous if found in the body of aquatic organisms and can be transferred through various types of organisms until it ends up in humans through the food web. This transfer of microplastics in the food web becomes an issue which threatens human health. Activity 3.5 (pgs. 102 – 103) Questions (pg. 103) 1. Used as an indicator for the presence of dissolved oxygen in the water sample. The methylene blue solution stays blue in a water sample rich in dissolved oxygen but will decolourise in a water sample which has less or no dissolved oxygen. 2. The shorter the time taken for the methylene blue solution to decolourise in the water sample, the lesser the dissolved oxygen in the water sample. 3. Pond (or river) water sample because the time taken for the methylene blue solution to decolourise is the shortest. Formative Practice 3.2 (pg. 105) 1. Land pollution, water pollution, air pollution, thermal pollution (any three) 2. (a) Eutrophication is the response of the ecosystem towards the addition of phosphate and nitrate ions (from detergents, fertilisers and rubbish) into an aquatic ecosystem. (b) Water pollution 3. (a) Air pollution (b) Air pollution, thermal pollution 4. (a) Biochemical Oxygen Demand (BOD) is the amount of dissolved oxygen needed by microorganisms such as bacteria to decompose organic substances. (b) The higher the BOD of a water sample, the higher the level of pollution of the water sample. 5. The time taken for methylene blue solution to decolourise in a water sample determines the level of pollution in the sample. The shorter the time taken for the methylene blue solution to decolourise, the higher the level of water pollution of the sample. 6. (a) Effective microorganisms comprise three types of microorganisms namely: • Lactic acid bacteria such as Lactobacillus casei • Photosynthetic bacteria such as Rhodopseudomonas palustris • Yeast (Saccharomyces cerevisiae) (b) Effective microorganisms treat polluted water as follows: • treat sewage • eliminate foul odour in water • stunt growth of dangerous microorganisms • increase dissolved oxygen • reduce BOD KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 7 10/28/20 12:26 PM
8 • facilitate the decay of organic substances to produce substances needed for the growth of green plants Formative Practice 3.3 (pg. 108) 1. Negative Emission Technologies are technologies that remove the content of carbon dioxide in the atmosphere. 2. Microalgae 3. Solar technology is one example of zero carbon emission because no carbon or carbon compounds are released by use of solar technology. 4. Environmental issues at the global level can only be successfully handled through actions coordinated by the United Nations (UN) involving members of various countries. Summative Practice 3 (pgs. 110 – 112) 1. (a) River water is the most polluted water sample compared to tap water, distilled water and pond water. (b) (i) Volume of water (ii) Type of water sample (c) River water (d) The higher the level of water pollution, the shorter the time taken for the methylene blue solution to decolourise. 2. (a) Paper bag (b) Paper takes a much shorter time to disintegrate. (c) Microplastic is a plastic piece measuring less than 5 mm in length. (d) Plastic bottle, plastic bag, plastic container, man-made textile, paint (any two) (e) • Carbon footprint of a product refers to the negative impacts to the sustainability of the environment caused by the product during its life cycle. • Carbon handprint of a product refers to the positive impacts to the sustainability of the environment caused by the product during its life cycle. 3. (a) Transport, use of fuel, personal activity, release of greenhouse gases, recycling, use of electrical energy, water, gas, waste, carbon balance (any four) (b) (i) Thermal pollution (ii) Water pollution (iii) Acid rain, global warming, climate change (any one) (iv) Physical, chemical or biological changes which jeopardize the environment 4. (a) Thermal pollution (b) • Air conditioners should be turned on at temperatures of 22°C – 25°C. • The inside and outside of air conditioners must be kept clean to increase energy efficiency. (or any other suitable answer) (c) • To dry wet clothes • To process food through drying or dehydrating such as dried shrimp • To defrost frozen food or drinks (any one) CHAPTER 4 Rate of Reaction Formative Practice 4.1 (pg. 124) 1. Example of a fast reaction: Burning of candle Example of a slow reaction: Photosynthesis (any other suitable answer is accepted) 2. Rate of reaction is the change in the quantity of reactants or products of a reaction per unit time. 3. (a) Average rate of reaction for the first 2 minutes = (60 – 0) cm3 120 s = 60 cm3 120 s = 0.50 cm3 s–1 (b) Average rate of reaction in the second minute = (60 – 40) cm3 (120 – 60) s KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 8 10/28/20 12:26 PM
9 = 20 cm3 60 s = 0.33 cm3 s–1 (c) Average rate of reaction for the whole reaction = 65 cm3 150 s = 0.43 cm3 s–1 Experiment 4.1 (pgs. 125 – 127) Questions (pg. 127) 1. Temperature of sodium thiosulphate solution (or temperature of reactant) 2. The higher the temperature of the reactant, the higher the rate of reaction. 3. Rate of reaction is shown by the reaction time taken for the ‘X’ on the piece of white paper to become no longer visible. Experiment 4.2 (pgs. 128 – 129) Questions (pg. 129) 1. Concentration of sodium thiosulphate solution (or concentration of reactant) 2. The higher the concentration of reactant, the higher the rate of reaction. Experiment 4.3 (pgs. 129 – 131) Questions (pg. 131) When the size of marble chips decreases, the rate of reaction increases. Experiment 4.4 (pgs. 131 – 133) Questions (pg. 133) 1. Presence of catalyst 2. Presence of catalyst increases the rate of reaction Brain Teaser (pg. 134) This is because solids cannot be compressed and it is difficult to compress liquids. Formative Practice 4.2 (pg. 134) 1. Temperature of reactant, concentration of reactant, size of reactant, catalyst and pressure 2. (a) higher (b) higher (c) smaller 3. Pressure Formative Practice 4.3 (pg. 136) 1. (a) Digestion of food (b) Rate of reaction in the digestion of food is increased with the presence of enzyme as a catalyst. 2. (a) Haber Process Temperature : 450°C – 550°C Pressure : 200 atm Catalyst : Iron filings (b) Contact Process Temperature : 450°C Pressure : 1 atm Catalyst : Vanadium(V) oxide Summative Practice 4 (pgs. 138 – 139) 1. (a) Process where one or more reactants are converted into one or more products. (b) Yes. Pressure affects the reaction for reactants in the gaseous state. 2. (a) (i) Size of marble chips/calcium carbonate (ii) Volume of gas collected (iii) Concentration of hydrochloric acid, volume of hydrochloric acid and mass of marble chips (b) The smaller the size of marble chips/ calcium carbonate, the higher the rate of reaction. (c) Volume of gas collected (cm3 ) 50.0 40.0 30.0 20.0 10.0 0 30 60 90 120 150 180 210 Time (s) • • • • • • • • • • • • Set I Set II KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 9 10/28/20 12:26 PM
10 (d) (i) Average rate of reaction in the first minute = Total volume of carbon dioxide gas collected in the first 60 seconds Reaction time in the first minute = 32.00 cm3 60 s = 0.53 cm3 s–1 (ii) Average rate of reaction in the first two minutes = Total volume of carbon dioxide gas collected in the first 120 seconds Reaction time in the first two minutes = 43.00 cm3 120 s = 0.36 cm3 s–1 (iii) Average rate of reaction in the second minute = Total volume of carbon dioxide gas collected from 60 s to 120 s Reaction time in the second minute = (43.00 – 32.00) cm3 (120 – 60) s = 0.18 cm3 s–1 (iv) Rate of reaction at the 60th second = (50.00 – 12.50) cm3 (120 – 0) s = 37.50 cm3 120 s = 0.31 cm3 s–1 (v) Average rate of reaction for the whole reaction = Total volume of carbon dioxide gas collected Reaction time = 45.00 cm3 150 s = 0.30 cm3 s–1 (e) Average rate of reaction for the whole reaction = Total volume of carbon dioxide gas collected Reaction time = 45.00 cm3 180 s = 0.25 cm3 s–1 3. (a) Protease, lipase (b) Protease increases the rate of decomposition of protein molecules to amino acid. Lipase increases the rate of decomposition of fat molecules to fatty acid and glycerol. (c) Temperature (d) Biological catalyst functions best at a temperature of 40°C. CHAPTER 5 Carbon Compounds Brain Teaser (pg. 142) Can be either an organic carbon compound or an inorganic carbon compound depending on the source of the compound. Formative Practice 5.1 (pg. 144) 1. Organic carbon compound is a carbon compound that originates from living things. 2. Inorganic carbon compound is a carbon compound that originates from non-living things. 3. Carbon monoxide, carbon dioxide, calcium carbonate, sodium hydrogen carbonate, aluminium carbide, potassium cyanide and carbon disulphide (any two) 4. Carbon cycle shows how carbon elements are recycled through the formation or decomposition of carbon compounds in life and organic substances in the environment through processes like respiration, burning, decomposition and photosynthesis. 5. Importance of carbon cycle: • maintains the natural balance of carbon • maintains the composition of carbon dioxide in the atmosphere KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 10 10/28/20 12:26 PM
11 Activity 5.2 (pgs. 146 – 147) Questions (pg. 147) 1. Fractional distillation 2. Petroleum is a mixture. Petroleum can be separated into petroleum fractions through a separation of mixture method, that is, fractional distillation. 3. (a) Petrol (b) Naphtha (c) Kerosene (d) Diesel 4. Different boiling points of petroleum fractions Formative Practice 5.2 (pg. 150) 1. Hydrocarbon is an organic carbon compound made up of only carbon and hydrogen elements. 2. Similarity: Saturated and unsaturated hydrocarbons are made up of only carbon and hydrogen elements. Difference: Saturated hydrocarbons have single covalent bond between carbon atoms but unsaturated hydrocarbons have at least one double covalent bond or triple covalent bond between carbon atoms. 3. Methane gas Activity 5.5 (pgs. 151 – 152) Questions (pg. 152) 1. Carbon dioxide 2. To produce pure ethanol 3. Ethanol has a lower boiling point than water. Activity 5.6 (pgs. 153 – 154) Questions (pg. 154) 1. Carbon dioxide and water 2. (a) Ester (b) • Fragrant smell • Insoluble in water 3. As a catalyst Formative Practice 5.3 (pg. 157) 1. Alcohol is an organic carbon compound which contains the elements carbon, hydrogen and oxygen. 2. Alcohol can be prepared through the process of fermentation using the action of yeast on food containing glucose or starch such as sugar, grapes, apples, sugarcane, rice, flour, potato and barley. 3. To separate ethanol from the mixture of glucose fermentation products 4. Solvent for organic substances, antiseptic 5. • Causes road accidents • Causes death • Endangers other road users Formative Practice 5.4 (pg. 160) 1. Fats are a type of organic carbon compounds containing the elements carbon, hydrogen and oxygen. 2. Butter from cow’s milk 3. Similarity: Organic compounds containing the elements carbon, hydrogen and oxygen. Difference: Sources of saturated fats are animals while sources of unsaturated fats are plants. 4. Jaundice, hypertension or high blood pressure, thrombosis, stroke, heart attack (any three) Activity 5.9 (pgs. 160 – 161) Questions (pg. 161) 1. To soften the pulp of the oil palm fruit 2. The quantity of oil extracted from the pulp is more than the quantity of oil extracted from the kernel. 3. Oil extracted from the pulp is red while oil extracted from the kernel is white or yellow. Formative Practice 5.5 (pg. 171) 1. (a) Pulp : Palm oil (b) Kernel : Palm kernel oil 2. To kill microorganisms which can spoil the palm oil fruits 3. (a) Water (b) Alcohol 4. Carotene, vitamin E Summative Practice 5 (pgs. 174 – 175) 1. (a) Fermentation (b) Organic carbon compound (c) Limewater turns cloudy (d) Carbon dioxide is released in the reaction between sugar and yeast. KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 11 10/28/20 12:26 PM
12 2. (a) Atherosclerosis (b) Cholesterol (c) Saturated fats (d) 1. Reduce the intake of fatty food 2. Eat unsaturated fats which can reduce the level of cholesterol in blood (any suitable answer) 3. (a) X: Pulp Y: Kernel Z: Shell (b) X: Palm oil Y: Palm kernel oil (c) (i) Sterilisation (ii) Digestion (iii) Filtration (d) 1. Does not contain cholesterol 2. Contains vitamin E 3. Contains carotene Compost Compost Roots Compost Pulp fibre Fruit Shell Fronds Fruit bunch Empty bunch Oil palm tree Tree trunk Wood Compost 4. CHAPTER 6 Electrochemistry Experiment 6.1 (pgs. 180 – 182) Questions (pg. 182) 1. Because bromine gas which is poisonous is released 2. To show the flow of electric current during electrolysis 3. In the solid state, ions in ionic compounds cannot move freely. Experiment 6.2 (pgs. 184 – 186) Questions (pg. 186) 1. (a) Magnesium ion, nitrate ion, hydrogen ion, hydroxide ion (b) Sodium ion, sulphate ion, hydrogen ion, hydroxide ion 2. Electrolyte Product formed at anode cathode Magnesium nitrate solution, Mg(NO3)2 Oxygen Hydrogen Sodium sulphate solution, Na2SO4 Oxygen Hydrogen 3. Electrolyte Ion selected to be discharged at anode cathode Magnesium nitrate solution, Mg(NO3)2 Hydroxide ion Hydrogen ion Sodium sulphate solution, Na2SO4 Hydroxide ion Hydrogen ion KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 12 10/28/20 12:26 PM
13 Experiment 6.3 (pgs. 187 – 188) Questions (pg. 188) 1. The concentration of chloride ions, Cl– in 1.0 mol dm–3 hydrochloric acid, HCl, is higher than the concentration of chloride ions, Cl– in 0.0001 mol dm–3 hydrochloric acid, HCl. 2. (a) Chlorine gas (b) Oxygen gas 3. (a) Chloride ion (b) Hydroxide ion Experiment 6.4 (pgs. 190 – 191) Questions (pg. 191) 1. Copper(II) ion, hydrogen ion, sulphate ion, hydroxide ion 2. (a) Hydroxide ion (b) Copper(II) ion Formative Practice 6.1 (pg. 192) 1. Battery Rheostat Anode (+) Cathode (–) A Electrolyte + – 2. During electrolysis, positive ions (cations) move to the cathode (negative electrode) and negative ions (anions) move to the anode (positive electrode). 3. Extraction of metal, purification of metal, electroplating of metal and wastewater treatment using electrocoagulation Formative Practice 6.2 (pg. 195) 1. A simple chemical cell is a device that can convert chemical energy into electrical energy. 2. Voltmeter Electrolyte Simple chemical cell Two different metals V 3. In a simple chemical cell, a metal which is positioned higher in the electrochemical series will act as the negative terminal while a metal which is positioned lower in the electrochemical series will act as the positive terminal. Summative Practice 6 (pgs. 197 – 198) 1. (a) Electrolysis is the process of decomposition of a compound in the molten or aqueous state into its constituent elements when electric current flows through it. (b) Copper(II) ion, Cu2+, hydrogen ion, H+, sulphate ion, SO4 2–, hydroxide ion, OH– (c) (i) At anode: Hydroxide ion At cathode: Copper(II) ion (ii) At anode: No ion is discharged At cathode: Copper(II) ion (d) Purification of metal 2. (a) (i) Sodium ion, Na+, hydrogen ion, H+ (ii) Nitrate ion, NO3 –, hydroxide ion, OH– (b) Electrode P (c) (i) Hydroxide ion (ii) Hydrogen ion (d) Sodium ions and hydrogen ions move to the cathode. The hydrogen ion is selected to be discharged because it is less electropositive compared to the sodium ion. KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 13 10/28/20 12:26 PM
14 3. The rusting of the iron nail can be avoided by electroplating the iron nail with copper through electrolysis under the following conditions: • iron nail is made the cathode • pure copper is made the anode • copper(II) sulphate solution is used as the electrolyte • electric current is supplied by an electrical source to carry out the electrolysis 4. (a) Three simple chemical cells, each made up of a potato with an iron nail and a copper rod poked into the potato and connected in series as in the figure below. (b) Three simple chemical cells, each made up of a potato with an iron nail and a copper rod poked into the potato and connected in parallel. CHAPTER 7 Light and Optics Activity 7.1 (pgs. 203 - 204) Questions (pg. 204) 1. So that the path of light rays before and after passing through the lens can be seen more clearly. 2. (a) The light rays converge (b) The light rays diverge 3. (a) Three parallel light rays which pass through the convex lens will converge at focal point, F. (b) Three parallel light rays which pass through the concave lens will diverge and appear as if from the focal point, F. Activity 7.2 (pg. 206) Questions (pg. 206) 1. Because objects in the laboratory are too close and light rays from them will not be parallel 2. Real, inverted and diminished 3. No because the image produced is virtual and will not be formed on the screen. Brain Teaser (pg. 209) Refer to Tables 7.3 and 7.4 Formative Practice 7.1 (pg. 209) 1. Convex lens 2. (a) (i) Lens X: Concave lens/ Diverging lens (ii) Lens Y: Convex lens/ Converging lens (b) (i) Lens X (ii) Lens Y (c) Focal point, F Focal point, F 3. Object is placed between focal point, F, and optical centre. Activity 7.3 (pg. 213) Questions (pg. 213) 1. So that the image formed is clearer. 2. Distance between objective lens and eyepiece = total focal length of objective lens and eyepiece 3. Normal adjustment Formative Practice 7.2 (pg. 215) 1. Image is virtual, upright and magnified 2. 30 + 5 = 35 cm KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 14 10/28/20 12:26 PM
15 Summative Practice 7 (pgs. 217 – 219) 1. (a) Focal length, f Focal point, Convex lens F (b) Focal length, f Focal point, F Concave lens 2. (a) F Virtual F image Object (b) Virtual, upright, magnified 3. (a) To produce images of different sizes using camera lenses of different focal lengths (b) (i) Where is the position of the object so that a virtual image is formed? (ii) R (iii) Virtual image P 2F Q F R F 2F Object (iv) Upright, magnified 4. Student’s answer CHAPTER 8 Force and Pressure Activity 8.1 (pgs. 222 – 223) Questions (pg. 223) 1. Water shoots out uniformly because equal pressure is exerted on the water. 2. Direction of push for piston Water Activity 8.2 (pg. 228) Questions (pg. 228) 1. • In figure (a), fluid does not flow, therefore, velocity is zero and has the same pressure. • In figure (b), when fluid passes through the narrow region, velocity of fluid increases and pressure in the region decreases. 2. The Venturi effect 3. Bernoulli’s principle Formative Practice 8.1 (pg. 230) 1. Pascal’s principle states that the transmission of pressure exerted on a fluid (liquid or gas) in an enclosed system is uniform throughout the fluid and in all directions. 2. The basic principle in a hydraulic system is the transmission of pressure in all directions based on Pascal’s principle. 3. Hydraulic jack system, hydraulic brake system, dental chair 4. Bernoulli’s principle states that a fluid moving at a higher velocity produces a lower pressure in that region. Summative Practice 8 (pg. 232) 1. (a) P1 (b) When air flows through the narrow space between the two cars, KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 15 10/28/20 12:26 PM
16 Activity 9.8 (pgs. 245 – 246) Questions (pg. 246) 1. To facilitate the reception of information without being blocked by walls or other parts of the building. 2. Navigational purposes 3. Google Maps, Waze Formative Practice 9.2 (pg. 247) 1. Global Positioning System (GPS) is a navigation system which gives information on location and time to its users in all weather conditions. 2. In GPS, • Control segment sends signals using Earth’s antenna found in the control station to GPS satellites in the space segment. • Signals received by GPS satellites are then corrected so that the clock/ time is accurate. • Corrected signals are then sent again by GPS satellites to GPS users in the user segment. 3. Navigational purposes and setting global clock or local standard time. 4. • Vehicles passing the affected road will reduce their speed • Informs users to be more careful about the possible presence of obstacles or objects on the road • Other users can choose alternative roads to avoid traffic jam Summative Practice 9 (pgs. 249 – 250) 1. (a) GPS satellite (b) For navigational purposes 2. (a) • GPS satellite is a communication satellite • Orbital height for a GPS satellite is 20 000 km • Orbital period for a GPS satellite is 12 hours (b) Smartphone (c) Navigational purposes (any suitable answer) (d) Google Maps, Waze the velocity of air flow increases and the pressure, P1 in the narrow space reduces. According to Bernoulli’s principle, when a fluid such as air passes through a narrow space, the velocity of the fluid flow increases and pressure in the space decreases. (c) Pressure P0 which is higher compared to P1 will cause both vehicles to be pushed towards each other until they collide. 2. Student’s answer CHAPTER 9 Space Technology Formative Practice 9.1 (pg. 243) 1. • Low Earth Orbit (LEO) • Medium Earth Orbit (MEO) • High Earth Orbit (HEO) • Geostationary Orbit (GEO) • Geosynchronous Orbit (GSO) 2. (a) (b) The apogee of a satellite in an elliptical orbit is the position of the satellite which is furthest from the planets or stars encircled by the satellite. The perigee of a satellite in an elliptical orbit is the position of the satellite which is closest to the planets or stars encircled by the satellite. 3. The higher the orbital height of a satellite, the lower the satellite velocity. 4. Hohmann transfer orbit is an elliptical-shaped orbit used to transfer launch vehicles between two orbits of different heights. 5. Due to zero-gravity condition at the ISS. 6. Increased risk of damage to satellites as a result of collision with the space junk. Perigee Apogee Earth KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 16 10/28/20 12:26 PM
17 3. (a) A: HEO B: MEO C: LEO D: GEO (b) MEO 4. Accurate and synchronised time information from the GPS satellite is used in the following daily activities: • In the field of transport Safety of flights and landing of aeroplanes as well as ship and train routes depend on accurate and synchronised time. • In the field of telecommunications Connections between handphones, live TV broadcasts and video conferences can be carried out continuously in accurately synchronised time. • In the field of science Accurate time and location of natural phenomena such as volcano eruptions, earthquakes and tsunami can be recorded. KSSM_2020_DLP_Science_Form_5_AnswerBook_ChitF.indd 17 10/28/20 12:26 PM