2023_NHT.pdf

2 0 2 4 SUPERVISOR TO ATTACH N H T PROCESSING LABEL HERE Write your student number in the boxes above. Letter Chemistry Q...

2 0 2 4 SUPERVISOR TO ATTACH N H T PROCESSING LABEL HERE Write your student number in the boxes above. Letter Chemistry Question and Answer Book VCE (NHT) Examination – Wednesday 22 May 2024  Reading time is 15 minutes: 2.00 pm to 2.15 pm Writing time is 2 hours 30 minutes: 2.15 pm to 4.45 pm Approved materials One scientific calculator Materials supplied Question and Answer book of 36 pages Data Book Multiple-Choice Answer Sheet Instructions Follow the instructions on your Multiple-Choice Answer Sheet. At the end of the examination, place your Multiple-Choice Answer Sheet inside the front cover of this book. Students are not permitted to bring mobile phones and/or any unauthorised electronic devices into the examination room.  Contents pages Section A (30 questions, 30 marks)  2–12 Section B (9 questions, 90 marks)  13–34 © VCAA 2024 Question 1 Which one of the following correctly compares fuel cells and galvanic cells? Galvanic cells Fuel cells A. use a stored supply of reactants use a continuous supply of reactants B. use a continuous supply of reactants use a stored supply of reactants convert electrical energy into convert chemical energy into C. chemical energy electrical energy convert chemical energy into convert electrical energy into D. electrical energy chemical energy Question 2 Which value can be calculated with data from a calorimeter? A. the standard electrode potential of a redox reaction B. the equilibrium constant of a chemical reaction C. the calibration factor of a chemical reaction D. the enthalpy change of a chemical reaction Question 3 Which one of the following statements is true of a scientific poster? A. The discussion section should identify outliers in the results. B. The introduction section should present the experimental procedures. C. The conclusion section should explain background chemical concepts. D. The results section should compare results with theoretical expectations. 2024 VCE (NHT) Chemistry Section A Page 3 of 36 Question 4 Catalysts A. increase the potential energy of the reactants in a reaction. B. shift the equilibrium position of the reaction. C. change the activation energy of the reaction. D. stabilise the products of the reaction. Question 5 Collision theory A. applies only to gases at standard temperature and pressure. B. explains why particles with a smaller surface area have a greater rate of reaction. C. asserts that a reaction only occurs if reactant molecules collide with kinetic energy at least equal to the activation energy. D. predicts that increasing the temperature increases the proportion of reactant particles that collide in the correct orientation. Question 6 Two substances are added to a test tube. When the reactants are mixed, the test tube becomes colder. Which one of the following is the correct description of the chemical reaction that occurs in the test tube? Energy is Reaction type converted to mass A. exothermic yes B. exothermic no C. endothermic yes D. endothermic no Question 7 What is the pressure of 3.0 mol of a gas in a 60 L container at 127 °C? A. 6.0 × 105 kPa B. 1.9 × 105 kPa C. 1.7 × 102 kPa D. 5.3 × 10 kPa Question 8 Faraday’s first law of electrolysis states, ‘the amount of substance produced at each electrode is directly proportional to the quantity of charge flowing through the cell’. Source: Which one of the following variables should be measured in an electrolytic cell to test Faraday’s first law of electrolysis? A. current through the circuit B. change in electrode volume C. voltage across the electrodes D. change in solution temperature Question 9 When 5.0 g of ethanol, C2H5OH(l), undergoes complete combustion in air, the mass of carbon dioxide, CO2 , gas produced is A. 2.4 g B. 4.8 g C. 9.6 g D. 19 g Question 10 Consider the following statements. 1 An energy profile diagram represents the enthalpy changes of an exothermic and an endothermic reaction. 2 Exothermic reactions have a higher activation energy barrier than endothermic reactions. Which of the statements is/are always true? A. 1 only B. 2 only C. both 1 and 2 D. neither 1 nor 2 Question 12 Which one of the following statements regarding fuel cells is correct? A. The state of the electrolyte can be aqueous, liquid or solid. B. The porous electrodes decrease the contact area for the reactants. C. During operation, gases move through the membrane. D. During operation, the cell voltage decreases because the reactants are used up. Question 13 The three unknown organic substances, X, Y and Z, were tested for their flashpoints. X had the highest flashpoint and Z had the lowest flashpoint. Consider the boiling points and viscosities of X, Y and Z. Which one of the following would show the same trend as the flashpoint? A. viscosity only B. boiling point only C. boiling point and viscosity D. neither boiling point nor viscosity Question 14 Which one of the following statements is correct for both electrolytic cells and galvanic cells? A. The anode is negative. B. The half-cells must be separated. C. The overall chemical reaction is exothermic. D. Electrons move from the anode to the cathode. Question 15 A sample of gas occupies a volume of 10.0 L at 25 °C and a pressure of 2.0 atm. The temperature of the gas is increased to 50 °C at constant pressure. Which one of the following is closest to the new gas volume after the temperature increase? A. 5.0 L B. 10 L C. 20 L D. 40 L Question 16 When a fat molecule is hydrolysed, three A. ester groups are formed. B. carboxyl groups are formed. C. water molecules are formed. D. glycerol molecules are formed. Question 17 The results below were recorded using a bomb calorimeter. Voltage 4.50 V Current 2.00 A Time 2.00 min Temperature change 1.50 °C What is the value of the calibration factor for the bomb calorimeter in J °C−1? A. 12 B. 27 C. 720 D. 1080 Use the following information to answer Questions 18 and 19. HPLC is used to separate a mixture containing methyl ethanoate, propanoic acid and butan-1-ol. This technique uses a polar stationary phase and a non-polar mobile phase to achieve separation. Question 18 Which one of the following options describes the state of the mobile phase and lists the three molecules in order of retention time from shortest to longest? State of Order of retention time from mobile phase shortest to longest A. gas propanoic acid, methyl ethanoate, butan-1-ol B. gas methyl ethanoate, butan-1-ol, propanoic acid C. liquid propanoic acid, methyl ethanoate, butan-1-ol D. liquid methyl ethanoate, butan-1-ol, propanoic acid Question 19 Which one of the following options is correct? A. The sample is vaporised before passing through the stationary phase. B. A calibration curve can be used to identify each component of the mixture. C. Pressure is applied to overcome resistance of the mobile phase in the column. D. A high retention time indicates that a component is highly attracted to the mobile phase. Question 20 H H C H O H C H H C C H H H H C H C H H H Which one of the following shows the correct IUPAC name and type of alcohol for the molecule above? Systematic IUPAC name Type of alcohol A. 2-methylpentan-3-ol secondary B. 4-methylpentan-3-ol secondary C. 2-methylpentan-3-ol tertiary D. 4-methylpentan-3-ol tertiary Question 21 Which one of the following skeletal formulas represents a product of the condensation reaction between methanoic acid and ethanamine? A. B. H N O N H O C. D. H N O N H O Question 22 Consider the following reaction. J(g) + L(g) ⇌ T(g);   ΔH is negative A reaction vessel containing J(g), L(g) and T(g) is initially at equilibrium. At time t1, the temperature of the reaction vessel is increased. Which graph best shows how the rate of the forward reaction changes after t1? A. B. reaction reaction rate rate time time t1 t1 C. D. reaction reaction rate rate time time t1 t1 Question 24 Which one of the following statements about energy profile diagrams is correct? A. The horizontal axis of an energy profile diagram is labelled ‘Time’. B. The shape of the energy profile diagram is not changed if one reactant is in excess. C. The energy profile diagram represents the average chemical energy of a reaction mixture. D. The energy profile diagram for a chemical reaction can be determined using a bomb calorimeter. Question 25 A dipeptide is shown below. O H H N O H H C H N C C H H O C C C N H H H H C H O H C H C O O H The correct names for the two amino acid residues in the dipeptide are A. glutamine and asparagine. B. glutamine and aspartic acid. C. glutamic acid and asparagine. D. glutamic acid and aspartic acid. Question 26 One molecule of chlorine gas, Cl2, reacts with one molecule of 2-methylbutane, C5H12, in the presence of UV light. The number of possible products that have an optical isomer is A. zero. B. one. C. two. D. three. Question 27 Lithium-ion cells are secondary cells used in mobile phones. Which one of the following statements about lithium-ion cells is correct? A. The extent of reaction increases after each recharge. B. A high battery voltage indicates a high rate of reaction. C. A high battery voltage indicates a high extent of reaction. D. The battery current is affected by the surface area of the electrodes. Question 28 The Maxwell-Boltzmann distribution describes a particular sample of gas. The area under the Maxwell-Boltzmann distribution curve represents the A. total number of particles in the sample. B. temperature of the particles in the sample. C. chemical energy of the particles in the sample. D. collision frequency of the particles in the sample. Question 29 Consider the methanol-oxygen, CH3OH/O2, fuel cell and an experimental galvanic cell. Both the fuel cell and the experimental galvanic cell are at standard laboratory conditions (SLC) and use an acidic electrolyte. The experimental galvanic cell is constructed using the following cell set up. CH3OH(aq) ∣ CO2(g) ∥ HCrO4(aq) ∣ Cr3+(aq) Which one of the following statements is correct for every mole of CH3OH reacted? A. At the positive electrode, the same amounts of water are produced in both cells. B. At the negative electrode, the same amounts of greenhouse gases are produced in both cells. C. At the negative electrode, the amount of greenhouse gases produced is lower in the experimental galvanic cell than in the fuel cell. D. At the positive electrode, the amount of water produced is lower in the experimental galvanic cell than in the fuel cell. Question 30 Five peaks in the 13C NMR spectrum of a pure amino acid are shown below. 200 180 160 140 120 100 80 60 40 20 0 ppm Source: The amino acid is A. valine. B. proline. C. glutamic acid. D. aspartic acid.