Secondary School, Kirkop

Transcription

1 KULLEĠĠ SAN BENEDITTU Secondary School, Kirkop Mark HALF YEARLY EXAMINATION 2017/18 Level: 5,6,7,8 YEAR 9 Chemistry TIME: 2 hours Question Global Mark Max. Mark Mark Instructions to students: Answer ALL questions. Calculators are allowed; Good English and orderly presentation are important. Read each question carefully. DO NOT WRITE ABOVE THIS LINE Name: Class: Below is a copy of the periodic table. Kulleġġ San Benedittu Secondary School Kirkop level 5-8 Page 1 of 8

2 Section A: Answer ALL questions in this section, using the spaces provided. This section carries 60 marks. 1. The following diagram shows the three states of matter and how they can be interchanged. a) Name the following changes from A to E. A B solid liquid gas C D E A) B) C) D) E) (5 marks) b) Name a substance which will undergo change E. (1 mark) c) This part of the question is about experiments involving the movement of particles. Some smoke is inserted in a smoke cell. Light is shone through it and observed under a microscope. The bits of smoke are lit up so bright specs are seen moving about randomly. (i) (ii) What is the name given to this kind of movement? Use the idea of particles to explain what causes the random movement of the bits of smoke. (3 marks) Kulleġġ San Benedittu Secondary School Kirkop level 5-8 Page 2 of 8

3 d) The apparatus was set up as shown below. (i) What term is used to describe the movement of gas particles? (ii) On the diagram, draw the result that is obtained during this experiment. (iii) Which gas particles travelled fastest? (3 marks) 2. Some processes used to separate mixtures are: filtration distillation fractional distillation chromatography evaporation sublimation Choose from the above list the most suitable method for each of the following separations: (i) To separate a mixture of different coloured inks. (ii) To separate a mixture of iodine and sand. (iii) To obtain some solid salt from a mixture of salt in water. (iv) To obtain a sample of pure water from tap water. (v) To separate a mixture of ethanol and water (vi) To separate a mixture of insoluble calcium carbonate and water (6 marks) Kulleġġ San Benedittu Secondary School Kirkop level 5-8 Page 3 of 8

4 3. The set up shows the apparatus needed to separate the different substances making black ink. a) What is the name of this separation method? (1 mark) b) Label the diagram where indicated. (3 marks) c) There are two mistakes in the set up. State what these are and suggest how these should be corrected. (4 marks) d) The diagram shows the end result from a similar experiment which was done properly. Underline the correct word so that the result is labelled in detail. most / least soluble substance most / least adsorbed substance e) Name two other coloured solutions that can be separated using this method. Kulleġġ San Benedittu Secondary School Kirkop level 5-8 Page 4 of 8

5 Two different atoms of oxygen exist: O and O 8 8 a) What term is used to describe these two different atoms of oxygen?. (1 mark) b) Complete the following table: Atom Number of protons Number of neutrons 16 O 8 18 O 8 (4 marks) c) A sample of oxygen gas contains 90% of 16 O and 10% of 18 O. Calculate the relative atomic mass of oxygen. 5. The smallest particles that can exist on their own are atoms. The table below gives some information about atoms of some elements. a) Complete the table by putting in the missing numbers. Element Symbol Atomic Mass Number of protons Number of neutrons Li 7 3 F 9 10 Al Mg Ar Electron Configuration (10 marks) Kulleġġ San Benedittu Secondary School Kirkop level 5-8 Page 5 of 8

6 c) Metals form ions when they react with non-metals. Using the information given in the above table, draw diagrams showing ALL the electron shells in: (i) An aluminium atom. (ii) An aluminium ion. 6. A Give the correct chemical formula for the following compounds: a) potassium chloride b) magnesium carbonate c) calcium hydroxide d) zinc nitrate e) sodium chloride B Give the correct chemical name for the following compounds: a) NaOH b) Cu(NO 3) 2 c) FeSO 4 d) H 2O e) MgCl 2 (5 marks) C. Balance the following chemical equations: a) CaCO 3(s) + HCl(aq) CaCl 2 (aq) + CO 2 (g) + H 2O(l) b) NaOH(aq) + H 2SO 4(aq) Na 2SO 4(aq) + H 2O(l) (4 marks) Kulleġġ San Benedittu Secondary School Kirkop level 5-8 Page 6 of 8

7 Section B: Answer any TWO questions from this section on the separate sheets provided. Each question carries 20 marks. 7. The following is a list of symbols to be used in your answers to the questions below: 23 Na 35.5 Cl 12 C 1 H a) Sodium chloride is an electrovalent (ionic) compound. (i) Give the electron configuration for the atoms of sodium and chlorine. (ii) Write the formula for sodium chloride. (1 mark) (iii) Draw dot / cross diagrams, showing ALL electron shells, to show the structure and charge for the sodium ion and chloride ion. (4 marks) (iv) Give two properties you would expect the ionic compound sodium chloride to have. b) Methane CH 4 is a covalent compound. (i) Give the electron configuration for an atom of carbon. (1 mark) (ii) State the number of electrons that the atoms of carbon and hydrogen need to share. (iii) Draw a dot / cross diagram, showing OUTER electron shells only, to show the bonding in a molecule of methane. (iv) Give two properties that you would expect the covalent compound methane to have. c) Hydrogen reacts with chlorine to form hydrogen chloride (HCl). (i) Name the type of bond present in hydrogen chloride. (1 mark) (ii) How is this type of bond formed? (1 mark) (iii) Draw a diagram of the bonding in hydrogen chloride showing how all the electrons in each atom are arranged. (Total 20 marks) Kulleġġ San Benedittu Secondary School Kirkop level 5-8 Page 7 of 8

8 8. The table below shows the melting points, boiling points and densities of substances A to D. Substance Melting point/ o C Boiling point/ o C Density/g cm -3 A B C D a) Which substance is a gas at room temperature? (1 mark) b) Which substance is a liquid at room temperature? (1 mark) c) Which substances are solids, at room temperature? d) Which substance will be a liquid at -260 o C? (1 mark) e) Which substance is a gas at 72 O C? (1 mark) f) What is the melting point of the least dense non-metal? (1mark) g) Draw diagrams to show how the particles are arranged in A and B (4 marks) h) Using the ideas of the kinetic theory explain what happens (i) to water molecules when a piece of ice is heated and finally melts. (ii) to a gas as it changes to a liquid on cooling. (iii) when solid carbon dioxide (dry ice) sublimes. (9 marks) (Total 20 marks) 9) Describe, how you would attempt to separate the following mixtures in the laboratory. In each case you should mention the apparatus required, and any important practical steps and precautions which you might take. Diagrams should be clearly drawn and labelled. a) a mixture of petrol and water (7 marks) b) a mixture of iodine and salt (7 marks) c) a mixture of insoluble calcium carbonate and water (6 marks) (Total 20 marks) END OF EXAM Kulleġġ San Benedittu Secondary School Kirkop level 5-8 Page 8 of 8