Summer Revision Worksheet Please read the following notes 1. It is advised that you do this work throughout your summer recess period. 2. It is obligatory 3. Revise the notes before every topic and then answer the questions below 4. All answers should be done on foolscap 5. Write the answers of each topic on separate foolscap 6. This will be collected during the first day of school 7. If you need any help email me on: [email protected] Basic Chemistry 1. a. The kinetic theory of matter tries to explain the physical properties of matter in terms of the motion of its particles. Explain: i. ii. iii. The movement of particles in shiny black crystals of iodine The movement of particles in violet iodine gas The movement of particles in iodine vapour contained in gas jar to another one above it containing air, even though iodine vapour is denser than air. (6) b. What does the fact that iodine sublimes on gentle heating show about the strength of forces between the iodine molecules in the solid? (1) c. Give an example of another solid that undergoes the same change in physical state as crystalline iodine, at room temperature and pressure. (1) 2. Complete these two sentences about separation of mixtures. i. ii. The separation of ink into its components is carried out by …. Water can be separated from oil using a…(2) Models of Matter 1. a. Using the Periodic table, give a well- labelled diagram showing the electronic configuration and the nuclear contents of the following atoms: i. ii. iii. Magnesium Phosphorus Chlorine (6) b. Would you expect the following to gain, loose or share electrons? i. ii. Magnesium Chlorine (2) c. Which would have the higher melting point: the compound formed from magnesium and chlorine or that from phosphorus and chlorine? Explain why (2) 2. a. Chlorine has two isotopes. Explain this statement (2) b. Give the number of protons, neutrons and electrons in the following isotopes. (4) Isotope Number of protons Number of neutrons Number of electrons 15 N 7 27 Al3+ 13 57 Fe 26 90 Sr 38 c. Write the electronic configuration of the elements nitrogen and aluminium (2) 3. a. The element lithium is in Group 1 of the Periodic Table. Give the formula of i. ii. iii. Lithium sulfate Lithium chloride Lithium nitrate (3) b. Draw a dot cross diagram to show the bonding in lithium sulfide. Show outer electrons only. (2) c. Name the gas produced when lithium reacts with hydrochloric acid (1) 4. a. Draw dot cross diagrams to show the bonding in: i. ii. Nitrogen molecule Ammonia (4) b. Name the type of bonding and the type of particles (eg: ions, molecules, etc.) present in i. ii. Sodium fluoride Methane (2) c. Iodine exists as shiny black crystals. What can be observed if a small crystal of iodine is heated in a test-tube? (1) 5. a. Use the Periodic Table to help you write the electronic configuration of i. ii. Lithium Sodium (2) b. By considering the position of Caesium, Cs, in the Periodic Table, state one similarity of its electronic configuration with those of lithium and sodium (1) c. An element Q has the electronic configuration 2,8,3. Give the formula of its chloride in terms of Q. (2) 6. This question concerns the elements E, F, G and H. (These letters are not the usual symbols of the elements concerned. Element E F G H Electronic configuration 2,8,2 2,8,3 2,8,7 2,8,5 Mass Number 24 27 35 32 a. Explain the term electronic configuration with the aid of a diagram(2) b. Give the number of protons and the number of neutrons of these for elements (8) c. Explain: i. ii. The difference between a molecule and an ion using the element G as an example The relationship between electronic configuration and whether an element is able to form a positive and negative ion. (4) d. Give the formula and one physical property of the compound formed between i. ii. E and G H and G In your answer give a dot and cross diagrams to show what happens to the electrons of the elements on combination. (6) Air and the atmosphere 1. A number of factors contribute to maintain the surface temperature of the Earth within very narrow limits at an average of 150C. One important mechanism for regulating the earth’s temperature is called the Greenhouse Effect. a. Name two gases/vapours that play a role in the greenhouse effect (2) b. Explain what would happen if the level of the greenhouse gases in the troposphere ( i.e. lower atmosphere) increases significantly. (2) c. A rise in temperature would lead to increase evaporation from lakes, rivers, seas and oceans. Explain how this event would add to global warming. (2) 2. This question is about the separation of gases found in air. Complete the following sentences: i. ii. iii. iv. 3. Air is a mixture of gases. Carbon dioxide is removed by passing through a U-tube containing… A U-tube filled with concentrated sulfuric acid removes…. Oxygen can be removed from the remaining mixture by ……… The final mixture would contain …. And… (5) a. Describe with the aid of a labelled diagram how you would prepare dry oxygen from hydrogen peroxide (your answer must include a balanced equation for the reaction) (5) b. How would you test for the presence of oxygen? (2) c. Briefly explain how oxygen is prepared in industry and give two uses of oxygen (2) d. Give the formula of: i. ii. iii. iv. An acidic oxide An amphoteric oxide A basic oxide A neutral oxide(4) e. Write an equation for the reaction of oxygen with: i. ii. Calcium Hydrogen (2) f. Explain why people are advised to roll themselves in a rug if their clothes catch fire (2) Water 1. a. Tap water is considered as hard water. Name one substance that causes temporary hardness in water and one substance that causes permanent hardness in water. (2) b. Give one method that can be used to soften hard water and state which of the hardness is removed (1) c. State one advantage of hard water (1) 2. Malta being an island is completely surrounded by sea water. As an experiment in the laboratory, a student wished to obtain some pure water from sea water a. Which one of the following do you suggest? (1) Filtration, distillation, evaporation, separation using a separating funnel b. For the method you mentioned in a. mention two pieces of apparatus that will be required. (2) c. In Malta large amounts of drinking water are obtained from sea. i. ii. Give the name of the process Why is this method preferred and not the one mentioned in a. (3) Acids, Bases and Salts 1. Hydrogen chloride gas was bubbled into two beakers, A and B. Beaker A contained water, while beaker B contained methylbenzene (toluene). The two resulting solution were tested using various substances and the observations were noted. Complete the Table below indicating any observations made. If no reaction occurred write ‘no reaction’ (6) Substances added Beaker A ( HCl + water) Beaker B (HCL + methylbenzene) Magnesium Powder Litmus indicator Solid sodium carbonate 2. a. From the list below choose two substances that are soluble in water to produce solutions which have an effect in litmus. (2) Sugar, oxygen, sand, nitrogen, carbon dioxide, ammonia, sulfur dioxide b. Water is not a good solvent for tar. i. ii. 3. Explain the term solvent Suggest a suitable solvent for tar (2) a. Choose from the following list, the two substances which dissolve in water to produce alkalis. (2) Zinc oxide, sodium nitrate, potassium hydroxide, sulfuric acid, barium hydroxide b. For the substances that you have chosen in a. what do you expect the pH to be: greater than 1, exactly 7, or less than 7. (1) c. Lead (II) nitrate can be prepared by neutralisation reaction. Give the names of the reagents required (1) d. Give a balanced chemical equation for the reaction that occurs in c. including state symbols (2) e. Solid lead (II) sulfate is one of the products obtained when a small amount of lead (II) nitrate solution is added to some magnesium sulfate solution. Give a balanced chemical equation for the reaction, including state symbols. (3) 4. Label the following aqueous solutions as strong or weak acids: i. ii. iii. Ethanoic acid nitric acid Hydrochloric acid (3) 5. Complete the following tables by: a. Giving one use for each material(3) Material Plaster of Paris Epsom salts Washing soda Use b. Giving the chemical formula for the main component of each material (3) Material Vinegar Milk of magnesia Quicklime Chemical formula 6. Write equations and explain how the following salts can be prepared in the laboratory: a. barium sulfate (3) b. calcium sulfate if the starting material is calcium carbonate (5) c. Copper (II) chloride (3) d. potassium nitrate (5) Moles 1. a. Define the term relative atomic mass of an element. (2) b. Calculate the relative molecular mass of i. ii. 2. PoCl3 C6H12O6 (2) A compound X contains carbon, hydrogen and chlorine. a. Find the empirical formula of X, given that it contains 37.2% carbon, 7.8% hydrogen, and 55.0% chlorine (3) b. Determine the molecular formula of compound X, if the relative molecular mass is 64.5. (2) 3. A piece of magnesium ribbon weighing 0.36g burns in oxygen to produce magnesium oxide. i. ii. iii. Give a balanced equation for the reaction (2) Calculate the number of moles of magnesium used in the experiment (1) Calculate the mass of magnesium oxide produced (3) 4. Determine the empirical formula of nicotine, a component of tobacco, given that it has the following composition by mass: 74.1% C, 8.6% H and 17.3% nitrogen (5) 5. a. For most calculations the relative atomic mass of magnesium is taken to be 24 but a more accurate value is 24.31. Suggest why the accurate relative atomic mass of magnesium is not exactly 24 (2) b. Which of the following will contain more atoms: 12g of carbon or 12g of magnesium? Give a reason for your answer. (2)