Grade 9 General Science Revision 2024-2025 PDF

Grade 9 General Science review TERM 1: 2024 - 2025 List the series of procedure to use the scientific methods to solve Textbook, 6, 7, 8 problem, and differentiate between types of variables, constant, and Figures 3, 4, control and assign them to an experiment (case study)...

Grade 9 General Science review TERM 1: 2024 - 2025 List the series of procedure to use the scientific methods to solve Textbook, 6, 7, 8 problem, and differentiate between types of variables, constant, and Figures 3, 4, control and assign them to an experiment (case study) Table 1 Dependent What we measure variable Independent What we change variable Constant Does not change control Standard by which results can be compared List the series of procedure to use the scientific methods to solve Textbook, 6, 9, 11 problem, and differentiate between theory and scientific law, & Figures 3, 6, define bias, & blind experiment 8 Bias occurs when a scientist’s expectations change how the results are analyzed or conclusions are formed. In science, activities are performed that test the validity Which of the following features should NOT of theories. be included in the scientific process? These activities are called: a. Experimental bias A. Hypotheses b. Hypothesis formation B. Experiments c. Theory development d. Observation C. Controls D. variables Identify the SI base unit for different quantities (Time, length, mass, Textbook, 12, 13 temperature, amount of a substance and electric current) Tables 2, 3 Convert between the SI base units using the prefixes Textbook, 14, 15, Figure 12 16, 18 Analyze and interpret data from given graphs (Pie, Line & Bar Textbook, p21, 22, graphs) Figures 15, 16, 23 17 Differentiate between states of matter and describe the thermal Textbook, p355, energy associated with changing between these states Figures 2, 4, 5, 356, 357 6 Particles move freely Particles vibrate in place Volume and shape change Volume and shape are to match container constant More kinetic energy Assumption 1 Little kinetic energy Particles slide past each other Volume is constant but shape change to match container Assumption 1 & 2 Less kinetic energy  Figure 6 Carbon dioxide (CO) turns from a solid directly to a gas. Because this gas is very cold, it Figure 5 As temperature causes water in increases, the particles that the air to condense, forming a white fog. make up a substance in its liquid state move faster. When Explain, at the molecular level, the behavior of CO2 their energy creates sufficient as it undergoes this phase transition. Figure 4 When ice is pressure to surpass the air Solid state- CO2 molecules are arranged closely placed in water, together - pressure above the liquid, the energy from the When heated - energy increases- weakening the liquid boils. particles of the liquid Infer What is inside the intermolecular forces and molecules break free water is transferred In boiling water, the bubbles of the boiling liquid? and enter the gaseous state. to the particles of bubbles are filled with When the gaseous CO₂ is released into the air, it solid ice, melting the water vapor (steam) is very cold, lower the temperature of ice and cooling the surrounding air, leading to the condensation of water water vapor present in the air. This process  Describe changes of state in terms of the attractive forces, and energy of Textbook p358 particles, Analyze all feature on heating curves. & Predict the effect of any , Figure 7 changes of matter on the curve. Heat energy is used to overcome the attractive Boiling point forces between particles. At temperature increases, particles start to move more freely Melting point Figure 7 Although thermal energy is added at a constant rate, the temperature of the water increases only at a, and e. At b and d, the added energy is used to overcome the attractions between the particles. Solid to liquid = heat of Infer how this graph would be different if 2.0 kg of water were being heated instead of 1.0 kg of water. How would fusion this graph be different if 0.5 kg of water were being heated Liquid to gas = heat of vaporization Perform calculations using the pressure equation, Pascal's Textbook, p364, 365, principle, and gas laws (Boyle's & Charles's laws) Figure 15, 19, 369, 370, 20 372 A car weighing 15,000 N is on a hydraulic lift platform measuring Figure 15 The pressure of 10 m2. What is the area of the smaller piston if a force of 1100 N the fluid on one side of a is used to lift the car? hydraulic lift is equal to the pressure on the other side. A diver who is 10.0 m underwater experiences a pressure of 202 kPa. If the diver’s surface area is 1.50 m2, with how much total force does the water push on the diver? A car weighs 15,000 N, and its tires are inflated to a pressure of 190 kPa. How large is the area of the car’s tires that are in contact with the road?  They expand until they break and fall Figure 20 As volume is decreased, a gas exerts increased pressure on the walls of its container. Figure 19 A weather balloon The three canisters are depicted on the graph. expands as it Interpret What happens to the volume of a gas if rises due to decreased external the pressure on that gas is doubled pressure. Eventually, the balloon ruptures, and the instruments fall back to the ground  A volume of helium occupies 11.0 L at a pressure of 98.0 kPa. What is the new volume if the pressure drops to 86.2 kPa? What would be the final size of the balloon in the example problem above if it were placed in a –18°C freezer? Identify and explain real-world applications of Bernoulli's Textbook, Figures p366, 367 Principle, such as in hose-end spray, airplane lift, and 16, 17, Questions tornadoes lift roofs off of buildings Low pressure Pressure decreases as fluid velocity increas High pressure pushes wing up Relate Charles’s Law and its graphical representation to practical Textbook, p371 applications, & compare between different gases and the effect of Figure 21 temperature on their volume Gas A As temperature increases, volume increase  Define Matter and how to classify it (Elements & Compounds) and Textbook, P378, give examples, differentiate between physical change and chemical Figure 4,11 380, change and the resulted matter from each change 384 Matter - Anything that has mass and takes up space Physical change Chemical change A physical change is a A chemical change is a change in size, shape, change in matter in form, or state of which the substances matter. that make up the The matter’s identity matter change into stays the same. other substances It can be reversed. with different chemical and physical properties  Sodium (element) + Chlorine (element) = Table salt (compound) The properties of sodium and chloride are different from the properties of table salt Figure 4 Chlorine, a poisonous gas, and sodium metal combine in a one-to-one ratio to form sodium chloride, or table salt. elements are the building blocks that combine to form compounds through chemical bonding. The properties of compounds are different from the elements that make up the compound. compounds can be formed and decomposed through chemical reactions. Differentiate between the properties of homogeneous & heterogeneous Textbook, p381, mixtures - give example on each, and the scattering of light in Tyndall figures 5, 7, 382, effect 8, 9, 11 383, Mixture 384 2 or more substances that are physically blended together. Homogeneous Heterogeneous Remains constant A mixture where and uniformly materials remain mixed separated Suspension Colloids Solution A mixture where Mixture of liquid Solute dissolves in and solid, where the particles never solvent the particles settle settle Figure 5 Many salad dressings are mixtures of oil, vinegar, and seasoning. Notice the visible herbs and spices floating in the salad dressings. Figure 7 River water is suspension that carries soil and sediment. If river water slows or sits undisturbed, the suspended particles settle out. contains visible solid particles that Explain - How are dispersed can you the throughout tellliquid, that river leading water is apotential to cloudiness, suspension settling over time, and the ability to be filtered. Figure 8 Fog is a colloid composed of water droplets suspended in air. Figure 9 Because of the Tyndall effect, a light beam is scattered by the colloid on the left but passes invisibly through the solution on the right. Compare between physical change and chemical change Textbook, p385, 386, with giving examples Figures, 12, 13, 387, 388, 389 14, 16, 17 Figure 12 Appearance is a physical property. Appearance includes color, shape, size, texture, and volume. Figure 16 Light can cause Compare the physical chemical changes that ruin the properties Rubber band of the rubber bands – elastic, healthy properties of some and the tennis ball flexible vitamins. The brown color of this Tennis ball – specific bottle protects the vitamins from shape light. Reaction to light is a chemical property  List the physical properties of matter and how to use them to Textbook, p386, 388 separate mixtures Figures, 13,15 Physical properties Size Size dependent independent Mass Boiling point Volume Melting point Density Solubility Conductivity magnetism  List the physical properties of matter and how to use them to Textbook, p386, 388 separate mixtures Figures, 13,15 Figure 14 Heating iron raises its temperature and changes its color. These changes are physical changes because it is still iron. Size - Magnetism - Physical Physical Figure 15 Distillation can separate liquids from solids dissolved in them. The liquid is heated until it evaporates and moves up the column. Then, as it touches the water-cooled surface of the condenser, it becomes liquid again. Physical property Identify where the solids would be found after distillation is complete After distillation is complete, solids can Explain how the law of conservation of mass applies to Textbook, Figure p391, 392 chemical changes, using calculations 19, Example problem & practice problems When methane reacts with oxygen, the products are carbon dioxide and water. How many grams of water are formed if 24 g of methane react completely with 96 g of oxygen to form 66 g of carbon dioxide? Mass of reactants = mass of products 24g Methane + 96g oxygen = 66g Carbon dioxide + ? Water Mass of water = 120g – 66g Mass of water = 54g  Compare and contrast between the atomic models that lead to Textbook, p402, 403 the modern one (electron cloud model) Figures, 4,5 Elements consist of tiny particles Spherical atom containing small, negatively And cannot be subdivided. charged particles. He called them atoms Discovered the electron (in blue) claimed that they were evenly spread Named – plum pudding model Discovered that the center of the atom is a suggested that electrons could nucleus which is positively charged jump between orbits as Electrons orbited the nucleus they absorb or release specific amounts of energy. Electrons move in circular motion around the nucleus Modern model of the atom which is accepted today Figure 5 Most of an atom is empty space. The electron cloud represents the area in which the electrons are Use the relationship between the atomic number, and the mass number to find Table 4 p405 number of protons, electrons, and neutrons for a given element from the periodic table protons = atomic number mass number = protons + neutron Neutrons = Mass number - = protons + = Explain how the isotopes of an element are alike and how they Textbook, Figure P406, 407 are different 7 Figure 7 Boron-10 and boron-11 are two isotopes of boron. These two isotopes differ by one neutron. Most naturally occurring elements have more than one naturally occurring isotope. Same Different Explain why these atoms are isotopes Same element Different number neutrons Same chemical Different mass properties number Same number protons Calculate the average atomic mass of an element Textbook, P407 Questions 6. Mass = protons + neutron Mass = 17 + 18 Mass = 35 8. it takes into account the different isotopes of that element and their relative abundances 9. Potassium 40 Number protons = 19 Neutrons = mass – protons Neutrons = 21 10. Cl 35 (Neutrons = 35 -17 = 18) Cl 37 (neutrons = 37 – 17 = 20) average atomic mass of chlorine - 35.45 amu Chlorine-35 is more abundant than chlorine-37. Use the periodic table to differentiate between the elements Textbook, p410, 415, chemical & physical properties, and assign the metal and Figures 9, 15, 1, 422, 427, nonmetals in any giving chemical compound or molecule. 7, 10, Questions 430, 434 On the left side Between metals Except for Hydrogen on and middle of and non-metals. the right side. Occurs as table Have properties of gasses and do not, Shiny, conduct both metals and conduct heat and heat and non-metals electricity electricity Use the periodic table to differentiate between the elements Textbook, p410, 415, chemical & physical properties, and assign the metal and Figures 9, 15, 1, 422, 427, nonmetals in any giving chemical compound or molecule. 7, 10, Questions 430, 434 Figure 1 The various properties of metals make them useful Describe some uses for metal sheets and wires eyeglass frames, computers, and buildings. Figure 7 Copper is often mixed with zinc or nickel to make modern coins. Gold, silver, and bronze—an alloy of copper and tin—are used to make athletic medals relative softness, malleability, attractive colors, resist corrosion Use the periodic table to differentiate between the elements Textbook, p410, 415, chemical & physical properties, and assign the metal and Figures 9, 15, 1, 422, 427, nonmetals in any giving chemical compound or molecule. 7, 10, Questions 430, 434 Figure 10 Humans are composed of mostly nonmetals. The pie chart breaks down the ratio of elements in the human body by mass (left). These elements mostly fall in the nonmetal portion of the periodic table (right Use the periodic table to differentiate between the elements Textbook, p410, 415, chemical & physical properties, and assign the metal and Figures 9, 15, 1, 422, 427, nonmetals in any giving chemical compound or molecule. 7, 10, Questions 430, 434 7. Solid Solid metals nonmetal Non malleable Malleable Non ductile Ductile Brittle and Excellent powdery conductors Poor 8. conductors Covalent bonding Shiny appearance ionic bonding 9. MgO - oxygen 11. full outer electron NaH - hydrogen shells AlBr3 - bromine high ionization energies, FeS - sulphur stable 12distinct colour and 10. Fluorine – toothpaste smell Chlorine - water Bromine – DNA studies Iodine - disinfectants Compare between metals and nonmetals and their physical and Textbook, p424, 425, chemical properties Figures 4, 12, 13 432, 433 Figure 12 Fluorine’s compounds have many uses Figure 4 Alkali metals are very reactive. For example, the vigorous reaction between potassium and water releases enough thermal energy to ignite the hydrogen gas that forms Figure 13 Halogens have a wide variety of uses and properties.