Physical Sciences Grade 12 P2 Limpopo Mock 2018 QP

=) Downloaded from hlayiso.com LIMPOPO PROVINCIAL GOVERNMENT Q (\C OU = REPUBLIC OF SOUTH AFRICA DEPARTMENT OF EDUCATION (Sale R \p MeV NATIONAL SENIOR CERTIFICATE } Mt “o F PHYSICAL SCIENCES P2: CHEMISTRY au i i ie u a SEPTEMBER 2018 4 MARKS: 150 TIME: 3 hours This question paper consists of 14 pages and 4-paged data sheets | Copyright reserved Please turn over |

Downloaded from hlayiso.com Physical Sciences/ P2 LimpopoDoE/September 2018 vse INSTRUCTIONS AND INFORMATION 10. 11. Copyright reserved Write your NAME in the appropriate space on the ANSWER BOOK. This question paper consists of TEN questions. Answer ALL the questions in the ANSWER BOOK. Start EACH question on a NEW page in the ANSWER BOOK. You may use a non-programmabie calculator. You may use appropriate mathematical instruments. YOU ARE ADVISED TO USE THE ATTACHED DATA SHEETS. Number the answers correctiy according to the numbering system used in this question paper. Give brief motivations, discussions, et cetera where required. Show ALL formulae and substitutions in ALL calculations. Round off your final numerical answers to a minimum of TWO decimal places. Write neatly and legibly Please turn over

Downloaded from hlayiso.com Physical Sciences/ P2 3 LimpopoDoE/September 2018 Nsc QUESTION 1: MULTIPLE- CHOICE QUESTIONS Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. Write only the letter (A — D) next to the question number (1.1 — 1.10) in the ANSWER BOOK. 1.1 Which ONE of the following pairs of compounds contain members of the same homologous series? A Cal, and C3Hs B C3He and CaHe Cc CH,O and CoH4O2 D CoH and C3HsO2 (2) 1.2 The following equation represents the cracking of a hydrocarbon at high temperature and pressure: CitHea > 2CoHa t+ ¥ + CaHio Which ONE of the following can be the IUPAC name of product Y? A Pent-1-ene B Pentane Cc Prop-1-ene D Propane (2) 1.3 2-chloro butane is strongly heated in the presence of concentrated sodium hydroxide. The major product that forms is: A But-t-ene B But-2-ene Cc Butan-1-ol D Butan-2-ol (2) 14 Consider the chemical reaction represented by the balanced equation below: CaCO3(s) + 2HCf(aq) = CaCto(s) + CO2(g) + H2O(£) Which ONE of the following changes will increase the rate of COs(g) production? A Increase in pressure. B Increase in the mass of CaCQ3. Cc Increase in the volume of HC£(aq). D increase in the concentration of HC2(aq). (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/ P2 LimpopoDoE/September 2018 1.5 1.6 1.7 1.8 nec The equilibrium in a closed container is represented by the following equation: 28029) + O2(g) = 28O3(g) AH<0 Which ONE of the following actions will increase both the K,-value and the concentration of SOs present at equilibrium? A Increasing the concentration of oxygen. B Decreasing the temperature. Cc Increasing the temperature. D Increasing the pressure at constant temperature. (2) Consider the following equation: CaO(s) + SO2(g) = CaSO,(s) if the equilibrium concentration of SO2(g) at 25 °C is equal to x mol-dm®, then the value of the equilibrium constant at this temperature will be equal to: A x B x? 1 Cc 1 D _ x (2) A solution has a pH of 1. This solution: A Is always a strong acid B Is always a weak base Cc Contains a higher concentration of H30* -ions than OH’ -ions D Contains a higher concentration of OH’ -ions than H30*-ions (2) MnO,‘(aq) ions are reduced by hydrogen sulphide (H2S) gas. The equation representing the oxidation half reaction is: HoS > 2H*+ S+2e 2H* +S + 2e > HS Mn?* + 4H20 — MnO,’ + 8H* + 5e" MnO, + 8H" + 5e° > Mn?" + 4H2O (2) UOWD Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/ P2 § LimpopoDoE/September 2018 NSC 1.9 Which ONE of the following pairs of metals will have the highest emf if they are used as electrodes in a standard electrochemical cell? (Use the redox table) A Zn and Cu B Pb and Hg Cc Zn and Ag D Fe and Pb (2) 1.10 The diagram below represents a cell which is used to refine copper. The impure copper contains silver and zinc . X fp CuSO, (aq) impure copper Be Which ONE of the following half reactions will occur at electrode X? A SO? + 4H* + 20" + SOo + HO B Cu Cu* +26 c Cu?* + 2e ~~ Cu D Zn** + 2e° > Zn (2) [20] Copyright reserved Please turn over

Downloaded from hlayiso.com | Physical Sciences/ P2 6 LimpopoDoE/September 2018 NSC QUESTION 2 (Start on a new page) 21 Consider the following two organic compounds: A. CH3 — CH2 — CH2 —- CH2- O—-H B. CH3;—CH2, -C-O-O-H 2.1.1. To which homologous series does compound B belong? (1) 2.1.2 Define the term isomers. (2) 2.1.3. Use STRUCTURAL FORMULAE and write down a functional isomer of compound B. (2) 2.1.4 Use STRUCTURAL FORMULAE and write a balanced equation for the reaction which occurs when A and B react. (4) 2.1.5 Give the IUPAC name of the organic product that forms in the (2) reaction mentioned in 2.1.4. 2.2 Write the IUPAC name of the compound represented by the structural formula below. H H I | H Cc H oH Cc H H H | | H Cc c= C Cc Cc H | | | | H H H H (2) [13] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/ P2 7 LimpopoDoE/September 2018 NSC QUESTION 3 (Start on a new page) The table below shows the results obtained during an experiment to determine the boiling points of some alkanes and alcohols with comparable molecular masses. Compound Relative Boiling molecular point (°C) mass A CH3CH3 30 -89 B CH30H 32 65 iS CH3CH2CHs 44 -42 D CH3CH30H 46 78 E CH3CH2CH2CH3 58 0 F CH3CH2CH20H 60 97 G CH3CH2CH2CH2CH3 72 36 H CH3CH2CH2CH20H 74 117 3.1 Define the term boiling point. (2) 3.2 Consider the boiling points of the four alkanes (A,C,E and G) in the above table. 3.2.1 What is the phase of G at room temperature? (1) 3.2.2 Describe the tendency in boiling points of the alkanes from A to G. (1) 3.2.3 How will the boiling point of a chain isomer of E compare with the boiling point of compound E? (Choose from HIGHER THAN, LOWER THAN or THE SAME.) Explain your answer. (2) 3.3 The boiling point of alcohol F is much higher than that of alkane E. Explain this observation by referring to the type and strength of intermolecular forces in alkanes and alcohols as well as the energy involved. (3) 3.4 3.4.1 Define the term vapour pressure. (2) 3.4.2 Howwill the vapour pressure of compound H compare with the vapour pressure of compound B? (Choose from HIGHER THAN, LOWER (1) THAN or THE SAME.) 3.5 Use structural formulae to draw a structural isomer of compound H which is also a tertiary alcohol. (2) [14] Copyright reserved Please turn over

Downloaded from hlayiso.com | Physical Sciences/ P2 8 LimpopoDoE/September 2018 NSC QUESTION 4 (Start on a new page) A learner decides to investigate certain reactions of pent-1-ene. He draws the following flow diagram to assist him: PONtane |g} Pent-1-ene Haloalkane 1 Haloalkane 2 Pent-1-ol 4.1 Pent-1-ene reacts with bromine water (Br2) at room temperature. 4.1.1. What is observed during the reaction? (1) 4.1.2 Name the type of addition reaction which occurs. (1) 4.2 Pent-1-ene reacts with HBr. 4.2.1 Use structural formulae to represent this reaction. (3) 4.2.2 Give the name of the major product in the above reaction. (2) 4.2.3 The learner wants to change this major product back to an alkene. Name a reactant as well as two reaction conditions which are needed in order to achieve this. (3) 4.3 The learner wants to change pent-1-ol into pent-1-ene. Give the formula of the catalyst needed for this reaction. (1) 4.4 Pent-1-ene reacts with a compound and forms pentane. 4.4.1 Give the NAME of the compound with which pent-1-ene reacted. (1) 4.4.2 Pentane reacts with oxygen. Write a balanced equation for this reaction by using molecular formulae. (3) 4.4.3 Is the reaction in 4.4.2 an exothermic or endothermic reaction? ‘ (1) [16] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/ P2 9 LimpopoDoE/September 2018 NSC QUESTION 5 (Start on a new page) The Haber process for the industrial preparation of ammonia can be represented by the following chemical reaction: 5.1 G2 5.3 Na(g) + 3H2(g) = 2NH3(g) AH<O 5.1.1 Is the reaction a homogeneous or a heterogeneous reaction? (1) 5.1.2 What is indicated by AH? (1) 5.1.3 Give the NAME of the catalyst which can be used in this reaction. (1) One of the ways in which the reaction rate can be increased is by increasing the concentration of No. Explain in terms of the collision theory why the reaction rate will increase. (3) Other methods to increase the reaction rate of this reaction are listed below: A: — Addition of a suitable catalyst B: Increasing temperature C: Increasing pressure by decreasing the volume of the container Use the letter A, B or C to indicate which of these methods will: 5.3.1 Decrease the amount of NHa(g) which is produced at equilibrium Explain. (4) 5.3.2 Have no effect on the amount of NHs3(g) which is produced at equilibrium (2) 5.2.3 increase the amount of NHs(g) which is produced at equilibrium (2) [14] Copyright reserved Please turn over

Downloaded from hlayiso.com | Physical Sciences/ P2 10 LimpopoDoE/September 2018 NSC QUESTION 6 (Start on a new page) 6.1 The first step in the Ostwald process for the manufacture of nitric acid is the catalytic oxidation of ammonia. A platinum alloy gauze is used as catalyst. The gauze is heated at the start of the process. The equation for the reaction is: 4NH,(g) + 502(g) = 4NO(g) + 6H2O(g) AH = -905 kJ-mol™ 6.1.1 Define the term catalyst. (2) 6.1.2 Why does the platinum alloy gauze remain warm during this process? (2) The second step in the Ostwald process takes place in a closed container and is represented by the following equation: 2NO(g) + O2(g) 2 2NO.(g) AH = -113 kJ-mol" 6.1.3. Use Le Chatelier’s principle to explain what effect the increase of pressure will have on the yield NO2. (3) 6.2 The equation below represents an equilibrium reaction in a sealed 1dm° container: NO2(g) + NO(g) = N2O(g) + O2(9) AH > 0 Equilibrium is reached at a certain temperature. The K- value at this temperature is 3,93 and the concentrations for each reactant and product in the container at equilibrium was: [NOz] = 0,06 mol-dm? [NO] = 0,29 mol-dm* [N20] = 0,18 mol-dm’* [Oz] = 0,38 mol-dm* One of the conditions which influence equilibrium is changed and a new equilibrium is reached. The concentration NO; at this new equilibrium is 0,12 mol-dm®. 6.2.1 Calculate the K, value at the new equilibrium. (8) 6.2.2 Name the condition which was changed and explain how it was changed. (2) [18] QUESTION 7 (Start on a new page) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/ P2 11 LimpopoDoE/September 2018 NSC 7.1 The concentrations of hydronium ions i (H30*) and hydroxide (OH) ina sample of sea water are 10°° mol-dm® and 10°° mol-dm? respectively. 7.1.1 _ Is the sea water acidic or basic? (1) 7.1.2 Calculate the pH of the sea water. (2) 7.1.3 Shells which consist mainly of CaCOs, are Possibly responsible for the pH of the sea water. Write down a balanced equation to confirm this statement. (2) 7.2 Asolution is prepared by adding 25,0 cm’ of a 0,20 mol-dm* NaOH solution to 40,0 cm? of a 0,15 mol-dm? HCI solution. The balanced equation for this reaction is: NaOH + HCl > NaCl + H2O 7.2.1 One of the reactants is in excess. Calculate the number of moles of this reactant which will be left at the end of the reaction. (7) 7.2.2 Calculate the pH of the final solution. (5) [17] Copyright reserved Please turn over

Downloaded from hlayiso.com | Physical Sciences/ P2 12 LimpopoDoE/September 2018 NSC QUESTION 8 (Start on a new page) 8.1 Two half cells, Fe (s)/Fe** (aq) and Oz (g)/H20 (2) in an acidic solution are used to set up an electrochemical cell. The cell works under standard conditions. 8.1.1 Write down the standard conditions which are applicable to this cell (3) 8.1.2 Which half- cell represents the anode? (2) 8.1.3. Write down the balanced equation for the oxidation half reaction. (2) 8.1.4. Write down the balanced equation for the reduction half reaction. (2) 8.1.5. Write down the cell notation for this cell. (3) 8.1.6 Calculate the emf of this cell. (4) 8.2 A magnesium rod is attached to underground iron pipes in order to prevent the pipes from rusting. Explain in terms of relative strengths of reducing agents how this is possible. (3) [19] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/ P2 13 LimpopoDoE/September 2018 NSC QUESTION 9 (Start on a new page) The simplified diagram below represents an electrochemical cell which is used for the electrolysis of a concentrated sodium chloride solution. Energy supply Concentrated NaCl (aq) Chiorine gas is given off at electrode Q. Write down the: 4 Electrode where reduction takes place (P or Q) (1) 9.2 Half reaction which occurs at electrode P (2) 9.3 Direction in which electrons flow in the external circuit (P to QorQ to P) (1) 9.4 NAME of the reducing agent in this reaction (1) 9.5 This process is used in the chloro-alkaline industry. Write down the FORMULAE of two products which are manufactured during this process, (2) [7] Copyright reserved Please turn over

Downloaded from hlayiso.com | Physical Sciences/ P2 14 LimpopoDoE/September 2018 NSC QUESTION 10 (Start on a new page) The flow diagram below represents processes which are used in the fertilizer industry. Process X Air 5 Nitrogen “T Ammonia ——— Acid R Ammonium sulphate 10.1 Write down: 10.1.1. The name of the industrial process X (1) 10.1.2 The name of the process used to manufacture acid R which is used to manufacture ammonium sulphate (1) 40.1.3 A balanced equation for the preparation of ammonium sulphate (3) 10.2 The following information appears on a 50 kg bag of fertilizer. - :Pik 3:1: 5 (30) 10.2.1. What does the N:P:K on the bag represent? (2) 10.2.2 Calculate the mass of nitrogen in the bag. (3) 10.2.3 Calculate the mass of filler in the bag. (2) [12] TOTAAL: 150 Copyright reserved Please turn over