GRADE 12 SEPTEMBER 2017 PHYSICAL SCIENCES …

1 NATIONAL SENIOR CERTIFICATE GRADE 12 september 2017 physical sciences P2 MARKS: 150 TIME: 3 hours This question paper consists of 23 pages, including 4 data sheets. *PHSCE2* 2 PHYSICAL SCIENCES P2 (EC/ SEPTEMBER 2017 ) Copyright reserved Please turn over INSTRUCTIONS AND INFORMATION 1. Write your full NAME and SURNAME in the appropriate spaces on the ANSWER BOOK. 2. This question paper consists of TEN questions. Answer ALL the questions in the ANSWER BOOK. 3. Start EACH question on a NEW page in the ANSWER BOOK. 4. Number your answers correctly according to the numbering system used in this question paper. 5. Leave ONE line between two subquestions, for example between QUESTION and QUESTION 6. You may use a non-programmable calculator. 7. You may use appropriate mathematical instruments. 8. You are advised to use the attached DATA SHEETS.

2 9. Show ALL formulae and substitutions in ALL calculations. 10. Round off your final numerical answers to a minimum of TWO decimal places. 11. Give brief motivations, discussions et cetera where required. 12. Write neatly and legibly. (EC/ SEPTEMBER 2017 ) PHYSICAL SCIENCES P2 3 Copyright reserved Please turn over QUESTION 1: MULTIPLE-CHOICE QUESTIONS Four possible options are provided as answers to the following questions. Each question has only ONE correct answer. Write only the correct letter (A D) next to the question number ( ) in the ANSWER BOOK for example E. Which ONE of the following about hydrocarbons is TRUE? Hydrocarbons always contain .. A single bonds only. B carbon and hydrogen atoms only. C carbon, hydrogen and oxygen atoms only. D double or triple bonds between carbon atoms only.

3 (2) A group of organic compounds with the same general formula is called a .. A polymer B macromolecule. C functional group. D homologous series. (2) The flow diagram below shows the conversion of compounds with the general formula CnH2n to other compounds. Inorganic reagent X Catalyst Y Which ONE of the following CORRECTLY gives the formula of catalyst Y and the formula of the inorganic reagent X? Formula of catalyst Y Formula of inorganic reagent X A Pd H2O B Pd Dilute KOH C H2SO4 H2O D H2SO4 Dilute KOH (2) Alcohols CnH2n CnH2n + 2 4 PHYSICAL SCIENCES P2 (EC/ SEPTEMBER 2017 ) Copyright reserved Please turn over Which ONE of the following reactions DOES NOT form part of the production of sulphuric acid (H2SO4) in the contact process?

4 A S + O2 SO2 B 2SO2 + O2 2SO3 C SO3 + H2O H2SO4 D SO3 + H2SO4 H2S2O7 (2) Niric acid (HNO3) ionises according to the equation: HNO3( ) + H2O( ) NO3 (aq) + H3O+(aq) Which ONE of the following is a CORRECT conjugate acid-base pair? A HNO3 and H2O B NO3 and H3O+ C HNO3 and NO3 D NO3 and H2O (2) When a chemical reaction reaches equilibrium .. A concentrations of the reactants and products are equal. B concentration of products is always higher than that of reactants. C the rate of the forward reaction equals the rate of the reverse reaction. D the rate of the forward reaction is higher than the rate of the reverse reaction. (2) (EC/ SEPTEMBER 2017 ) PHYSICAL SCIENCES P2 5 Copyright reserved Please turn over The reaction between nitrogen dioxide and carbon monoxide is represented by the equation below.

5 NO2(g) + CO(g) NO(g) + CO2(g) The potential energy diagram for the reaction is given below. With reference to the energies represented by P, Q and R the activation energy for the reverse reaction is: A R P B Q + R C R Q D P Q (2) Sodium hydroxide pellets (NaOH) are added to water until the following equilibrium is established: NaOH(s) + H2O ( ) Na+ (aq) + OH-(aq) The pH of the solution is 8,5. When a few drops of a concentrated solution of sodium chloride (NaC ) are added to the equilibrium mixture the pH of the equilibrium mixture will be.

6 A equal to 7. B lower than 8,5. C higher than 8,5. D unchanged at 8,5. (2) R Potential energy (kJ/mol) Course of reaction Q P 6 PHYSICAL SCIENCES P2 (EC/ SEPTEMBER 2017 ) Copyright reserved Please turn over The following redox pairs are used in a galvanic cell. Sn4+/ Sn2+ and Ag+/ Ag Which substance is the STRONGEST reducing agent? Refer to the Table of Reduction Potentials. A Sn4+ B Ag+ C Sn2+ D Ag (2) The electrochemical cell below is used for the electrolysis of a concentrated solution of sodium chloride (NaC ). Consider the following statements regarding the cell: I Sodium (Na) is formed at electrode Q II The chloride ion is the oxidising agent. III The solution is alkaline when the reaction is complete. Which of the above statements is/are TRUE? A I only B II only C III only D I and III only (2) [20] Q P (EC/ SEPTEMBER 2017 ) PHYSICAL SCIENCES P2 7 Copyright reserved Please turn over QUESTION 2 (Start on a new page.)

7 The letters A F in the table below represent six organic compounds. 1 A Hexane B O CH3 C CH2 CH2 CH3 C C3H6O2 D Propanoic acid E H CH2CH3 Br H C CH C CH3 H CH2CH3 F H H C C H H n Use the information in the table to answer the QUESTIONS to Write down the LETTER that represents a compound that is: A ketone (1) A large molecule composed of smaller monomer units covalently bonded to each other in a repeating pattern (1) Write down the IUPAC name of: Compound B (2) Compound E (3) Compound C is prepared by the reaction of methanol with a carboxylic acid in the presence of concentrated sulphuric acid.

8 Write down the: Name of the homologous series to which compound C belongs (1) STRUCTURAL FORMULA of the carboxylic acid used (2) STRUCTURAL FORMULA of compound C (2) Compound D is one of the STRUCTURAL ISOMERS of compound C. Define the term structural isomer. (2) Write down the IUPAC name of another STRUCTURAL ISOMER of compound C, other than compound D. (2) 8 PHYSICAL SCIENCES P2 (EC/ SEPTEMBER 2017 ) Copyright reserved Please turn over Compound A undergoes a cracking process in which shorter chain hydrocarbons X and Y are produced according to the equation: Classify the cracking process as CATALYTIC or THERMAL. (1) Shorter chain hydrocarbon X is a monomer of compound F shown in the table. Write down the MOLECULAR FORMULA of compound Y. (1) [18] High Pressure High Temperature Hexane Y X + (EC/ SEPTEMBER 2017 ) PHYSICAL SCIENCES P2 9 Copyright reserved Please turn over QUESTION 3 (Start on a new page.)

9 The flow diagram below shows various organic reactions. D A HBr Is propan-2-ol a PRIMARY, SECONDARY or TERTIARY alcohol? (1) NAME the type of reaction represented by: A (1) B (1) C (1) Write down the STRUCTURAL FORMULA of the haloalkane. (2) Use STRUCTURAL FORMULAE to write down a balanced equation for reaction C. (5) Reaction B takes place in the presence of a strong base. Is the base used in reaction B DILUTE or CONCENTRATED? (1) [12] propan-2-ol alkene haloalkane C 10 PHYSICAL SCIENCES P2 (EC/ SEPTEMBER 2017 ) Copyright reserved Please turn over QUESTION 4 (Start on a new page.)

10 Vapour pressure values for compounds E and F are shown in the table below. The data was obtained at the same temperature of 20 C using equal volumes of the compounds E and F. COMPOUND VAPOUR PRESSURE (in kPa at 20 C) E Ethanoic acid 0,5 F Propan-1-ol 2 Define the term vapour pressure. (2) Besides the two control variables underlined above, write down another control variable for this comparison. (1) Give a reason why hydrogen bonds in compound E are stronger, than in compound F. (1) Learners carried out an investigation into the factors that affect the boiling points of compounds A to D shown in the table below. The results of the investigation are shown in the table below. COMPOUND NUMBER OF METHYL SIDE CHAINS (BRANCHES) IN ISOMER BOILING POINT ( C) A CH3CH2CH2CH2CH2CH3 68 B CH3 CHCH2CH2CH3 CH3 60 C CH3 CH3 CCH2CH3 CH3 50 D CH3 CH3 CHCHCH3 CH3 57,9 Explain the trend in the boiling points from A to C.