Grade 9 End semester exam Revision sheet Answer key. Kingdom of Bahrain Ministry of Education Ahlia School -ABCD

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1 Grade 9 End semester exam Revision sheet Answer key Question 1: Directions: Put a check mark in the column that each type of matter describes. 1. Oxygen Substances Element Compound Mixtures 2. Granite 3. Air 4. hydrogen 5. NaCl 6. salad dressing 7. Water 8. Soil 9. Methane 10. Carbon 11. Blood 12. CO2 13. Helium 14. fruit salad 15. Nitrogen 16. salt water 17. Sodium chloride 18. Tomato soup 19. Copper Question 2: Directions: Complete the sentences with suitable words: 1. Almost all matter can be classified into two major categories substances and Mixtures 2. Matter that is made up of the same combination of atoms is called an Element 3. Substances that are physically blended but not chemically bonded together are called Mixtures

2 4. Mixtures have Different amounts of the same substances. 5. Two types of mixtures are homogeneous and Heterogeneous 6. Matter that is made up of chemically bonded atoms from two or more elements is called a Compound 7. An example of a homogeneous solution is Air. 8. Properties of a Compound can be different from the properties of its elements. 9. The properties found in a Mixture are the same before and after mixing has taken place. 10. Physical methods can separate Mixtures. 11. A chemical change is needed to separate Compounds. 12. Some of the properties of the substances that make up a mixture can be observed in the mixture. 13. Air is a Homogeneous mixture 14. Water (H2O) is a Compound. 15. Parts of Solutions a. The substance that exists in the greatest quantity in a solution is called the. b. The substances that exist in lesser quantities in a solution are. 16. Types of Solutions a. Water can exist in three different States. of matter as solids, liquids, or gases. 17. Water as a Solvent a. Water is a(n) polar molecule, which means that one end of the molecule has a slightly negative charge and the other end has a slightly Positive charge.

3 18. Like Dissolves Like a. polar solvents dissolve polar solutes easily. b. non-polar solvents dissolved nonpolar solutes easily. c. Water molecules are polar, so the charged ends of the molecules are attracted to the oppositely charged ends of other polar molecules, which make it easy for polar solutes to dissolve in water. d. Ionic compounds are formed of alternating positive and negative charges e. The charged ends of a(n) polar molecule, such as water, are attracted to the ends that have the opposite charges. f. Ionic compounds, such as sodium chloride, dissolve easily in water. 19. Concentration How much is dissolved? a. The amount of a particular solute in a given amount of solvent is called the Concentration. b. The concentration of a solute in a given quantity of solution can be stated using two measurements mass, which is often stated in grams, and Volume, which is usually stated in liters. c. To calculate the concentration of a solution made of a solid solute and a liquid solution using mass and volume, you divide the mass of the solute by the volume of the solution. d. If a solution is made of two solids or two gases, then the concentration of the solution is given as a(n) percentage. 20. Solubility How much can dissolve? a. The maximum amount of solute that can dissolve in a given amount of solvent at a given temperature and pressure is called solubility. b. A solution that contains the maximum amount of solute the solution can hold at a given temperature and pressure is a(n) saturated solution. c. A solution that can still dissolve more solute at a given temperature and pressure is a(n) unsaturated solution. d. Changing the temperature or the will pressure change the solubility of a solution. 21. How Fast a Solute Dissolves a. Increasing the amount of contact between particles of a solute and the heat will cause the solute to dissolve faster.

4 Question3: Directions: Use the tables below to answer the following questions. Electronegativity Values for Some Elements H = 2.1 Li = 1.0 Be = 1.5 B = 2.0 C = 2.5 N = 3.0 O = 3.5 F = 4.0 Na = 0.9 Mg = 1.2 Al = 1.5 Si = 1.8 P = 2.1 S = 2.5 Cl = 3.0 K = 0.8 Ca = 1.0 Ga = 1.6 Ge = 1.8 As = 2.0 Se = 2.4 Br = 2.8 Electronegativity Difference Type of Bond 0.0 to 0.4 Covalent (nonpolar) >0.4 to <1.0 Covalent (somewhat polar) 1.0 to 2.0 Covalent (very polar) Greater than 2.0 Ionic 1. a. Which type of bond forms between potassium (K) and bromine (F)? K= 0.8, F=4.0; =3.2; 3.2 is greater than 2: Ionic bond b. Will the substance dissolve in water? Yes, it will dissolve in water. Polar solvent (water) dissolves the ionic solutes 2. a. Which type of bond forms between hydrogen (H) and sulfur (S)? H= 2.1, S=2.5; =0.4; 0.4 is covalent non polar b. Would the substance be more likely to dissolve in water or a nonpolar solvent? It is more likely to dissolve in nonpolar solvent; because like dissolves like 3. Identify the following bonds as ionic, nonpolar covalent, or polar covalent. a. H and Br = 0.7 covalent somewhat polar b. Cl and F = 1.0 covalent very polar c. K and Cl = 2.2 Ionic d. Li and O = 2.5 Ionic e. C and O = 1.0 covalent very polar f. H and H = 0.0 covalent non polar 4. Which of the compounds in question 3 would be most likely to dissolve in water? Cl and F, K and Cl. Li and O & C and O

5 Question 4: solve the following problems a. Leon tests the hummingbirds preference for different concentrations of sugar. He makes another sugar solution that has 200 g sugar and 2 L of water. What is the concentration of this sugar solution? b. Leon decides that the hummingbirds like a sugar solution that has a concentration of 105 g/l. If Leon makes 4 L of this solution, how many grams of sugar should he use? c. Nora dissolves 24 g of sugar into a pot of tea to make a sugar concentration of 16 g/l. What is the volume of the solution? d. How many times farther from the Sun is Neptune (distance = AU) than Uranus (distance = AU)? e. How many times farther from the Sun is Neptune (distance = AU) than Saturn (distance = 9.58 AU)? Concentration = mass 200 g C = 2 L C = 100 g/l Volume Mass = Concentration X Volume m= 105 g/ L X 4 L m = 120 g Volume = V = 24 g 16 g/ L V = 1.5 g/l Ratio: Neptune Uranus Au = Au = 1.57 Ratio: Neptune Saturn Au = 9.58 Au = 3.18 mass Concentration Question 5: Directions: On each line, write the term that correctly completes each sentence. Properties of Acids and Bases Acids Bases Have Ph Lower than 7 Have Ph Lower than 7

6 Sour in taste Bitter in taste Strong acids burn skin and eyes Strong bases burn skin and eyes Releases H3O + when dissolve in water Releases OH - when dissolve in water Question 6: Directions: On each line, write the term from the word bank that correctly completes each sentence. Some terms may be used more than once or not at all. astronomical closer comet elliptical energy farther faster foci focus gas giants gravitational inner outer planet revolve rotate slower solar system stars Sun The night sky offers a fascinating view into space. Most of the specks of light in the night sky are (a.) stars. They exist far beyond our (b.) solar system. The largest object in our solar system is the (c.) sun, which produces an enormous amount of (d.) energy. The Sun also applies a(n) (e.) gravitational pull on the planets. When you look into the night sky, you might see light reflected off a(n) (f.) planet, such as Venus. Objects in space (g.) revolve around the Sun along a stretched-out circle called a(n) (h.) elliptical orbit. Planets also (i.) rotate, or spin. There are four (j.) inner planets that are made up mostly of solid rocky materials. These objects are spherical and have a mass larger than the total mass of all other objects whose orbits are nearby. There also are four (k.) outer Planets made of gases, including helium and hydrogen. These four planets are sometimes termed (l.) gas giants. Distance in space is measured in (m.) astronomical units. A planet s speed changes as it orbits the Sun. A planet that is close to the Sun moves (n.) faster than a planet that is far from the Sun. Also, planets that are (o.) farther from the Sun have longer periods of revolution than planets that are closer to the Sun. The shape of a planet s orbit is determined by two (p.) focus points. These (q.) foci are equal distances from the center of the ellipse.

7 Question 7: Directions: Add information to the chart to compare and contrast planets in the solar system. Inner Planets (4) Outer Planets (4) Names of Planets Planet Composition Mercury Venus Earth Mars Rocks & metals Jupiter Saturn Uranus Neptune Gases Question 8: Directions: Complete the chart about the inner planets by answering each question in the space provided. Planet Atmosphere Structure Surface Moons Mercury Why does Mercury not have an atmosphere? Because it has small mass that cannot hold an atmosphere Which two metals make up the core? Iron and Nickel What covers the surface? Rocks How many moons does Mercury have? No moons Venus What makes up the atmosphere? CO2 What is different about this planet s rotation? It rotates from east to west What covers 80 percent of the surface? Solidified lava How many moons does Venus have? No moons

8 Earth What does the atmosphere support? What type of core does Earth have? What makes up most of Earth s crust? How many moons does Earth have? The life Solid inner core Liquid outer core Large broken plates one Mars What makes up about 95 percent of the atmosphere? CO2 What covers the polar caps? Frozen CO2 and ice What causes the reddish color? Iron oxide in its soil How many moons does Mars have? two moons Question 9: Directions: Explain each fact about the inner planets in the space provided. a. FACT Mercury craters last for billions of years. Because there is no atmosphere, no erosion occurs b. FACT Venus is covered by a thick layer of clouds. Venus is covered by acidic clouds which increases the atmospheric pressure 90% more that earth b. FACT The atmosphere of Venus is very dense with an atmospheric pressure that is 90 times greater than Earth s. Because it has no water, it is covered by acidic clouds

9 c. FACT Mercury experiences temperature extremes. Because there is no wind that regulates the temperature across the surface d. FACT Mercury does not experience a greenhouse effect. There is no atmosphere to trap the solar heat and increase the surface temperature e. FACT Venus is hotter than Mercury even though Mercury is closer to the Sun. because of the greenhouse effect Question 10: Directions: Complete the compare-and-contrast chart by writing terms from the list in the correct spaces. diameter of planet distance from the Sun gases change to liquid strong gravitational force hydrogen and helium gases lack a solid surface period of revolution mainly liquid interiors Mass number of moons size of rings small solid core Temperature tilt of rotation period of rotation type of rings

10 How are the outer planets similar? 1. gases change to liquid 2. strong gravitational force 3. hydrogen and helium gases 4. lack a solid surface 5. mainly liquid interiors 6. small solid core How are the outer planets different? 1. diameter of planet 2. distance from the Sun 3. period of revolution 4. Mass 5. number of moons 6. size of rings 7. temperature 8. tilt of rotation 9. period of rotation 10. type of rings Question 11: Directions: Complete the chart about the outer planets by answering each question in the space provided. Planet Atmosphere Structure Jupiter 2. What gases make up Jupiter s atmosphere? Hydrogen and Helium 4. What happens at about 1,000 km below the cloud layer? Hydrogen gas turns into liquid due to the high pressure 3. What is the Great Red Spot? A storm 5. What do scientists suspect the core might be made of? Iron and rocks

11 Saturn 7. What gases make up Saturn s atmosphere? H & He 9. In what ways is Saturn like Jupiter? The atmosphere gases and the structure 8. How thick is the atmosphere? 1000 Km Uranus 11. What gases make up the atmosphere of Uranus? Hydrogen, Helium and Methane 12. What lies below the atmosphere of Uranus? Slushy layer of water and ammonia 13. What do scientists think about the core? Solid rocky core Neptun e 15. What gases make up Neptune s atmosphere? Hydrogen, Helium and Methane 16. What are the dark circular areas? A storm called the great dark spot 17. What is the composition of the interior? Slushy layer of water and methane Solid core 18. What is the composition of the core? rock and iron core

12 Question 13: Directions: a. Complete this concept map by writing the correct term Weathering and erosion break rock into sediment. uplift brings rock to the surface. Sediment is laid down through deposition Existing rock melts and cools, forming igneous rock. Colliding plates push rock underground. Heat and pressure cause rocks to undergo metamorphism. b. Identify two rock cycle processes from the diagram that are related to plate tectonics. Metamorphism & Uplifting c. Identify two rock cycle processes from the diagram that are not related to plate tectonics. Erosion & deposition

13 Question 14: Directions: Answer each question or respond to each statement on the lines provided. a- State the evidence for the existence of liquid water on Mars in the past. Its polar caps are covered by ice b- Explain why the layers of colorful bands of clouds on Jupiter? Jupiter s fast rotation stretches the clouds into swirling bands c- Define the term high solubility? More of the substance can dissolve in the solvent d- List two factors affecting the solubility of a substance? Pressure and temperature e- List three examples of everyday acids & List three examples of everyday bases Acids: Fruits like strawberry, plastic, lactic acid in milk, fertilizers & cleaners Bases: foods like coffee beans, shampoo, detergents & papers f- State the relationship between the number of hydronium ions and hydroxide ions in a neutral solution. Write the chemical formula for each ion as part of your answer. In a neutral solution; such as water: the number of hydronium ions and hydroxide atoms are equal. H 3O + + OH - = 2H 2O g- List two methods that can be used to measure the ph of a solution. ph indicators, ph strip & ph meter h- Describe the two types of planets motion. Rotation: spin around their axis Revolution: orbit the sun i- Explain what causes objects to orbit the Sun? The sun s gravitational force

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