Angel International School - Manipay 1 st Term Examination November, 2017

Transcription

1 Grade 10 Angel International School - Manipay 1 st Term Examination November, 2017 CHEMISTRY Duration: 2.30 Hours Index No:- Part 1 Choose the correct answer and circle the number neatly 1) As we move across period electro negativity a) Decreases b) Increases c) remains same d) becomes zero 2) Metals difficult to oxidize are called A. weak metals B. strong metals C. noble metals D. none of above Answer 3) As we move across period from left to right, reactivity of metals with oxygen a) Decreases b) Increases c) remains same d) zero 4) Identify what this diagram represents. a) A pure lattice b) An impure substance c) An element d) A compound 1 P a g e

2 5) A student carries out an experiment to determine the effect of different types of salt solutions on an iron nail. Identify the purpose of the test tube containing the nail and water only. a) This test tube acts as a control for the experiment. b) This test tube allows a comparison between copper nitrate and copper sulphate. c) The water is added to test the strength of the nail. d) All of the answers are correct. 6) Aluminium is a) Above carbon in the reactivity series b) Above calcium in the reactivity series c) below hydrogen d) middle of the series 7) Metals from basic hydroxide which of the following metal hydroxide is the least basic? a) Mg(OH) 2 b) Ca(OH) 2 c) Sr(OH) 2 d) Ba(OH) 2 8) Two chemical processes are described below. In the combustion of methane, energy is In the electrolysis of molten lead(ii) bromide, energy is Which words correctly complete gaps 1 and 2? 2 P a g e

3 9) The diagram shows the energy profile of a chemical reaction. Two energy changes are labelled X and Y. Which statement about the reaction is correct? a) The activation energy of the reaction is X + Y. b) The enthalpy change of the reaction is X c) The enthalpy change of the reaction is X + Y. d) The reaction is exothermic 10) suspension of slaked lime in water is known as a) Lime water b) Quick lime c) Milk of lime d) Aqueous solution of slaked lime 11) Metals from basic hydroxide which of the following metal hydroxide is the least basic? a) Mg(OH) 2 b) Ca(OH) 2 c) Sr(OH) 2 d) Ba(OH) 2 12) Aluminium is... 3 P a g e

4 a) Above carbon in the reactivity series b) Above calcium in the reactivity series c) below hydrogen d) middle of the series 13) Aluminium is used to make... a) Aircraft b) Bridges c) Boats d) All of the above 14) What is the compound present in cassiterite? a) Zinc sulphide b) Lead(II) sulphide,nacl c) SnO 2 d) CuFeS 2 15) Find the true statement in below a) Copper react with water and form copper hydroxide b) Calcium react with steam to give carbon dioxide c) Aluminium react slowly to form oxide layer when heated d) Gold can react with water 16) Which of the metals will give the biggest voltage when combined with the copper electrode in an electrochemical cell? a) Zinc b) Tin c) Magnesium d) Oxygen 17) What is the name of the ionic compound formed from lithium and bromine? a) lithium bromine b) lithium bromide c) lithium bromium d) lithium bromated 18) What is the formula for sodium sulfate? a) NaSO 4 4 P a g e

5 b) Na 2 SO 4 c) Na(SO 4 ) 2 d) Na 2 (SO 4 ) 2 19) The solution of ash obtained after burning magnesium ribbon in air will turn. a. Red litmus to blue because it is acidic in nature. b. Blue litmus to red because it is basic in nature. c. blue litmus to red because if is acidic in nature. d. Red litmus to blue because it is basic in nature.\ 20) x is the product formed when sulphur reacts with oxygen, it dissolves in water to produce y Choose correcl oplion for x and y. X Y a SO 2 Acid b SO 3 Neutral c SO 2 Base d SO 3 Acid 21). Sodium metal is stored in x because it reacts vigoursly to produce y Choose the correct option for x and y. X Y a Water Acidic oxide b Alcohol Neutral oxide c Kerosene Basic oxide d Air tight container Acidic carbonate 22). Metal x reacts vigorously with water to produce gas y which burns with the pop sound Choose the correct option for x and y. X y a Sodium Oxygen b Magnesium Oxygen c Sodium Hydrogen d Sodium Sodium oxide 33 Formative Assessment Manual for Teachers Metals and Non-Metals - Chapter 3 5 P a g e

6 23) Read the following statements carefully and select the correct statements about the physical and chemical properties of metals- I. All metals are ductile II. Generally metals are ductile III. Metals which are more reactive than hydrogen react with acids to release hydrogen gas. IV. All metals react with acids to release hydrogen gas. The correct statement of the above area a) 1 and IV b) I and III c) II and III d) II and IV 24) Aluminum foil is used for wrapping food because a) It is ductile b) It is malleable c) It is a good conductor of heat d) It is sonorous 25) What happens when dilute sulphuric acid is poured on a copper plate? a. No reaction takes place b. Zinc sulphate formed c. Copper chloride formed d. Copper sulphate formed. 26) Which material is hard in nature? a. Iron b. Graphite c. Oxygen d. sodium 11. Which one of the following metal is used in thermo meters? a. Copper b. Mercury c. Aluminum d. Iron 27) Correct the statement by substituting the x and y with correct option. X can t be drawn into wires because it is not Y in nature. X Y A Coal Ductile B Copper Malleable C Aluminum Ductile d Coal Malleable 6 P a g e

7 Metals and Non-Metals Formative Assessment Manual for Teachers 28) Zinc replaces copper from _X solution because it is Y than copper. Substitute X and Y with correct option. X Y a Zinc sulphate Less reactive b Copper sulphate more reactive C sulphuric acid more reactive d Copper sulphate Less reactive 29) Most metallic oxides area. Acidic is nature b. Neutral in nature c. Basic in nature d. Amphoteric in nature 30) X is used for decorating sweets because it is_y in nature? Substitute X and Y with correct choice. X Y A Silver foil Ductile b Copper foil Malleable C Aluminum foil Ductile d Silver foil Malleable (30 marks) 7 P a g e

8 SECTION A Answer only one question. This section carries 10 marks. 1a. Use the knowledge of periodic table to find the name of: (i) (ii) an alkali metal the element whose atoms contain 6 protons (iii) a transition metal which is in period 4 (iv) (v) an element which exists as a liquid at room temperature the most reactive non-metal b. Use the given periodic table to find the symbol of: (i) (ii) (iii) (iv) (v) the most reactive metal the element whose atoms contain 4 electrons an element which is magnetic a very reactive metal which has to be stored under oil a very good electrical conductor commonly used in wires 2 State the colour of: a. solid iodine b. K + in flame test c. universal indicator in dilute hydrochloric acid d. Cu 2+ (aq) in flame test e. the Bunsen flame in which a crystal of sodium chloride is placed (10 marks) f. the substance which results when water is removed from hydrated copper (II) sulfate g. metal, which is used in photography h. catalysts, used in decomposition of hydrogen peroxide i. catalysts, which are on a solid honeycomb surface j. catalyst, used in fermentation of sugar (10 marks) 8 P a g e

9 SECTION B Answer Three questions including first, on the paper provided. This section carries 50 marks. 1) Ozone molecules are continually being broken down and formed in the upper atmosphere. (a) The equation shows one way in which ozone is formed in the upper atmosphere. O2 + O O3 ΔH = 392 kj / mol (i) Explain, in terms of bond breaking and bond forming, why this reaction is exothermic.. (ii) When one mole of oxygen molecules reacts, 392 kj of energy is released. Calculate the amount of energy released when 48.0 g of oxygen molecules react. energy released =... kj (iii) Name a pollutant that depletes ozone in the upper atmosphere.... (b) Ozone molecules decompose into oxygen molecules in a reversible reaction. 2O 3(g) 3O 2(g) ΔH = +143 kj / mol The reaction reaches equilibrium if carried out in a closed system. (i) The reaction is studied at a temperature of 400 C. Describe and explain what happens to the position of equilibrium if the pressure is increased... (ii) The reaction is studied at 25 atmospheres pressure. Describe and explain what happens to the position of equilibrium if the temperature is decreased... (iii) Describe and explain what will happen to the rate of the reaction if the temperature is decreased.. [Total: 10] 9 P a g e

10 2) In the laboratory oxygen gas is produced by the action of manganese (IV) oxide on hydrogen peroxide. (ii) What is the function of manganese (IV) oxide in this reaction? (iii) Copy and complete the following chemical reaction: (ii) List two uses of oxygen. (iii) Redraw the following diagram on your sheet H 2 O 2 (l) 2H 2 O( ) + O (g) [3] Label the items indicated on the diagram that show the equipment and materials used to produce dry oxygen. a The equipment used above is set up of three sections; the purification system, the collection system and the generator system. On your diagram in part d, draw 2 dotted lines to separate the three different parts and label each part accordingly. f. Give a chemical test for oxygen and state what is observed. [8] [4] (20 marks) 10 P a g e

11 3) a. Ammonia is an important chemical that has many uses. i) What is the name of the industrial process by which ammonia is produced? ii) What are the raw materials that are needed to produce ammonia? iii) Name the catalyst that is used in this reaction. What are the conditions in terms of temperature and pressure that are required for iv) this reaction to occur? v) Give the chemical equation including state symbols for this process. [3] vi) Give one use for ammonia. b. In 1831, a British vinegar merchant by the name of Peregrine Phillips, devised an economical way of producing concentrated sulfuric acid that is still in use today. i) What is the name of this process? ii) Sulfur is the raw material from which this process begins. It is heated in air to produce an oxide of sulfur. Give the chemical equation for this reaction. iii) This oxide of sulfur is reacted with more oxygen in the presence of a catalyst at a particular temperature and pressure. Give the chemical equation including the conditions required. [5] iv)the above process produces sulfur trioxide which is then mixed with concentrated sulfuric acid to produce oleum. Oleum is then mixed with water to produce more concentrated sulfuric acid Why is this step taken instead of mixing sulfur trioxide directly with water? v) During this process, some of the sulfur oxides escape from the factory. What type of aerial pollution do they form? (20 marks) 11 P a g e

12 4) a. Redox reactions occur when two substances undergo a particular change at the same time. Ritienne decided to investigate one such reaction by burning a piece of magnesium. (i) (ii) (iii) (iv) State two observations that Ritienne could note when the piece of magnesium is burnt in air. Give one important safety precaution related to this experiment. Name the apparatus that Ritienne should use to weigh, as accurately as possible, the magnesium oxide. Magnesium reacts with oxygen to produce magnesium oxide. Explain which element is being oxidized in terms of oxygen. [4] b. Ritienne collected the magnesium oxide on the watch-glass. It was found to weigh 8 g. Magnesium reacts with oxygen according to the following equation: 2Mg(s) + O 2 ( ) 2MgO( ) (i) (ii) (iii) (iv) (v) Copy the above equation and add the missing state symbols. Use the periodic table to find the mass of 1 mole of magnesium oxide. How many moles of magnesium oxide are present in 8 g of the compound? Use the equation to find the number of moles of magnesium needed to produce 8 g of magnesium oxide. Show your working. Change your answer in b. (iv) to grams. Remember that one mole of magnesium has a mass of 24 g. [4] ****** (20 marks) 12 P a g e