Mayar International Schools Chemistry IGCSE Past Paper Worksheet 5 PDF

Mayar International Schools First Semester 2024/2025 IGCSE Subject: Chemistry 0620 Grade: 9 Teacher: Rasha N. Maraqa Student’s Name:________________________________________ Grade: 9...

Mayar International Schools First Semester 2024/2025 IGCSE Subject: Chemistry 0620 Grade: 9 Teacher: Rasha N. Maraqa Student’s Name:________________________________________ Grade: 9 International (IGCSE) Sections: 9Ci2, 9Gi2, 9Fi1, 9Bi1 1 Code: FIPP-12 Issue No.: 01 1. Which diagram correctly shows the ions present in the compound potassium fluoride? (1) 2 Code: FIPP-12 Issue No.: 01 2. The electronic structures of atoms X and Y are shown. (1) X and Y form a covalent compound. What is its formula? 3. Two atoms of magnesium, Mg, react with one molecule of oxygen, O2. What is the formula of the product? (1) 4. Compound X melts at 801 °C and is a good electrical conductor when dissolved in water. Compound Y boils at 77 °C, is insoluble in water, and is a non-conductor of electricity. Which type of bonding is present in X and Y? (1) 3 Code: FIPP-12 Issue No.: 01 5. In the following diagrams, X and Y are atoms of different elements. Which diagram correctly shows the arrangement of outer electrons in a molecule of methane? (1) 6. Carbon and silicon are elements in Group IV. They both form oxides of the type XO2. (a) Silicon (IV) oxide, SiO2, has a macromolecular structure. (i) Describe the structure of silicon(IV) oxide. (3) (ii) State three properties that silicon (IV) oxide and diamond have in common. (3) 4 Code: FIPP-12 Issue No.: 01  (b) Explain why the physical properties of carbon dioxide are different from those of diamond and silicon(IV) oxide. (1) (c) Explain why the formula is SiO2, not SiO4. (2) 7. Use the following ions to determine the formulae of the compounds. (2) Ions OH– Cr3+ Ba2+ SO4 2– Compounds: (i)chromium(III) sulfate (ii) barium hydroxide 5 Code: FIPP-12 Issue No.: 01 8. The table below shows the elements in the third period of the Periodic Table, the number of electrons in their outer energy level, their oxidation state in their common compounds, and their melting points. (i)Explain why Na, Mg, and Al are good conductors of electricity. (1) (ii)Which element exists as diatomic molecules of the type X2? (1) (iii) Silicon has a similar structure to diamond. Explain why silicon has the highest melting point in the period. (2) 6 Code: FIPP-12 Issue No.: 01 9. Lithium bromide is an ionic compound. It can be electrolyzed when it is molten or in aqueous solution. It cannot be electrolyzed as a solid. Solid lithium bromide is a poor conductor of electricity. The ions cannot move to the electrodes, they are held in an ionic lattice by strong forces. (i) Describe the motion of the ions in the solid state. (1) (ii) Define the term ionic bond. (1) (iii) What is meant by the term ionic lattice? (2) 10. The table shows the melting points, boiling points, and electrical properties of five substances, A to E. Choose a substance from the table above to match each of the following descriptions. A substance may be used once, more than once, or not at all. Justify each choice with evidence from the table. 7 Code: FIPP-12 Issue No.: 01 (i) This substance is covalent and is a solid at room temperature (25 °C). Evidence (ii) This substance has a giant covalent structure. (3) Evidence: (iii) This substance is an ionic solid. (3) Evidence: 8 Code: FIPP-12 Issue No.: 01 11. Calcium reacts with nitrogen to form the ionic compound calcium nitride, Ca3N2. (a) Draw a diagram, based on the correct formula, which shows the charges on the ions and the arrangement of the electrons around the negative ion. Use o to represent an electron from a calcium atom. Use x to represent an electron from a nitrogen atom. (3) 12. Graphite is a form of carbon. Why can graphite be used as a lubricant? (1) A. Graphite contains delocalized electrons that move throughout the structure. B. Graphite contains weak covalent bonds so the atoms move easily. C. Graphite has a low melting point so it easily turns into a liquid. D. Graphite has weak forces of attraction between layers so they can move. 13. In which compounds are pairs of electrons shared between atoms? (1) 1. methane 2. lead bromide 3. sodium chloride A. 1 only B. 2 only C. 1 and 3 D. 1, 2 and 3 9 Code: FIPP-12 Issue No.: 01 14. Rescuers are drilling through fallen rock to rescue some men trapped in a cave. The drill needs lubricating from time to time. The following statements were made about the materials used for the drill tip and the lubricant and the reasons for their use. (1) 1. Diamond was used for the drill tip as it does not conduct electricity. 2. Diamond was used for the drill tip as it is very hard. 3. Graphite was used as the lubricant as it conducts electricity. 4. Graphite was used as the lubricant as it is soft and flaky. Which statements are correct? A. 1 and 3 B. 1 and 4 C. 2 and 3 D. D 2 and 4 15. The diagram shows the structures of some substances containing carbon. 10 Code: FIPP-12 Issue No.: 01  Answer the following questions about these substances. (a) Which substance, A, B, C, D, E or F. (3) (i) Has an ionic structure? (ii) Is a product of respiration? (iii) Is used for cutting? (b)Substance D is an element. Explain why substance D is an element. (1) 16. Magnesium reacts with chlorine to form magnesium chloride, MgCl2. Magnesium chloride is an ionic compound. (i) Complete the diagrams to show the electronic structures of the ions in magnesium chloride. Show the charges on the ions. 11 Code: FIPP-12 Issue No.: 01  (ii) Give three physical properties that are typical of ionic compounds such as MgCl2. (3) 17. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of ethyne, H–C≡C–H. Show outer shell electrons only. 12 Code: FIPP-12 Issue No.: 01 18. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of hydrogen sulfide. Show outer shell electrons only. 19. Hydrogen sulfide has a simple molecular structure. Explain why hydrogen sulfide has a low boiling point. (2) 20. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of chlorine. Show outer shell electrons only. 13 Code: FIPP-12 Issue No.: 01 21. The diagrams show the structures of four substances, R, S, T, and U. State which one of these substances, R, S, T, or U: (5) (i) Is a compound (ii) Conducts electricity when solid. (iii) Has the lowest melting point. (iv) Is a macromolecule. (v) Can act as a catalyst. 22. The diagrams show the structures of four substances, R, S, T, and U. (i) Which two of these substances, R, S, T, or U, are covalently bonded? (2) 14 Code: FIPP-12 Issue No.: 01  (ii) Which two of these substances, R, S, T, or U, conduct electricity when solid? (2) (iii) Which substance, R, S, T, or U, has the lowest melting point? (1) (iv) Which one of these substances, R, S, T, or U, is soluble in water? (1) 23. Potassium iodide is an ionic compound. (i) Describe what happens, in terms of electron loss and gain, when a potassium atom reacts with an iodine atom. (2) (ii) Describe the structure of solid potassium iodide. You may draw a diagram. (2) (iii) Explain why potassium iodide has a high melting point. (2) 15 Code: FIPP-12 Issue No.: 01 24. Explain, in terms of particles, why carbon dioxide is a non-conductor of electricity. (1) 25. Carbon and silicon are elements in Group IV. They both form oxides of the type XO2. (a) Silicon(IV) oxide, SiO2, has a macromolecular structure. (i) Describe the structure of silicon (IV) oxide. (3) (ii) State three properties that silicon (IV) oxide and diamond have in common. (3) (b) Explain why the physical properties of carbon dioxide are different from those of diamond and silicon(IV) oxide. (1) 26. Deduce the formulae of the following ions. (2) (i)selenide: (ii) gallium : 16 Code: FIPP-12 Issue No.: 01 27. Lithium bromide is an ionic compound. It can be electrolyzed when it is molten or in aqueous solution. It cannot be electrolyzed as a solid. (a) Solid lithium bromide is a poor conductor of electricity. The ions cannot move to the electrodes, they are held in an ionic lattice by strong forces. (i) Describe the motion of the ions in the solid state. (1) (ii) Define the term ionic bonding. (2) (iii) What is meant by the term ionic lattice? (2) 28. Two macromolecular forms of carbon are graphite and diamond. The structures of graphite and diamond are given below. 17 Code: FIPP-12 Issue No.: 01 (a) Explain in terms of its structure why graphite is soft and is a good conductor of electricity. (3) (b) Explain in terms of its structure why diamond is a very hard material that is used for drilling and cutting. (2) (C) Explain why graphite is a good conductor of electricity while diamond is a poor conductor. (2) (D)State two uses of graphite that depend on the above properties. (2) - It is soft. - It is a good conductor of electricity. 18 Code: FIPP-12 Issue No.: 01 29. Strontium oxide is an ionic compound. Draw a diagram that shows its formula, the charges on the ions, and the arrangement of the valency electrons around the negative ion. The electron distribution of a strontium atom is 2 + 8 + 18 + 8 + 2. Use (o) to represent an electron from a strontium atom. Use (x) to represent an electron from an oxygen atom. (3) 19 Code: FIPP-12 Issue No.: 01