IB Topics 1 & 11 Multiple Choice Practice 1. How many atoms of nitrogen are there in 0.50 mol of (NH 4) 2CO 3? 1 2 3.01 10 23 6.02 10 23 2. What is the value of x when 32.2 g of Na 2SO 4 xh 2O are heated leaving 14.2 g of anhydrous Na 2SO 4? M r(h 2O) = 18; M r(na 2SO 4) = 142. Na 2SO 4 xh 2O (s) Na 2SO 4 (s) + xh 2O (g) 0.1 1 5 10 3. What information is provided by 1 H NMR, MS and IR for an organic compound? I. 1 H NMR: chemical environment(s) of protons II. MS: fragmentation pattern III. IR: types of functional group I and II only I and III only II and III only I, II and III 4. How many grams of sodium azide, NaN 3, are needed to produce 68.1 dm 3 of N 2 (g) at STP? Molar volume at STP = 22.7 dm 3 mol 1 ; M r(nan 3) = 65.0 2NaN 3 (s) 3N 2 (g) + 2Na (s) 32.5 65.0 130.0 195.0 5. A student performs an acid-base titration using a ph meter, but forgets to calibrate it. Which type of error will occur and how will it affect the quality of the measurements? Random error and lower precision Systematic error and lower accuracy Systematic error and lower precision Random error and lower accuracy 6. What is the sum of the coefficients when the following equation is balanced using the smallest whole numbers? C 6H 12O 6 (aq) C 2H 5OH (aq) + CO 2 (g) 4 5 9 10 1
7. Which compound has the greatest percentage by mass of nitrogen atoms? N 2H 4 NH 3 N 2O 4 NaNO 3 8. Which statements about mixtures are correct? I and II only I and III only II and III only I, II and III 9. What can be determined about a molecule from the number of signals in its 1 H NMR spectrum? Bonds present Molecular formula Molecular mass Number of hydrogen environments 10. What is the density, in g cm 3, of a 34.79 g sample with a volume of 12.5 cm 3? 0.359 0.36 2.783 2.78 11. 5.0 cm 3 of 2.00 mol dm 3 sodium carbonate solution, Na 2CO 3(aq), was added to a volumetric flask and the volume was made up to 500 cm 3 with water. What is the concentration, in mol dm 3, of the solution? 0.0050 0.0040 0.020 0.010 12. What is the Index of Hydrogen Deficiency (IHD) for 1,3,5-hexatriene (C 6H 8)? 1 3 5 6 13. What is the expression for the volume of hydrogen gas, in dm 3, produced at STP when 0.30 g of magnesium reacts with excess hydrochloric acid solution? Mg(s) + 2HCl(aq) MgCl 2(aq) + H 2(g) Molar volume of an ideal gas at STP = 22.7 dm 3 mol 1 2
14. What is the sum of the coefficients when the equation is balanced with whole numbers? C 8H 18(g) + O 2(g) CO(g) + H 2O(l) 26.5 30 53 61 15. How many moles of oxygen atoms are there in 0.500 mol of hydrated iron(ii) ammonium sulfate, (NH 4) 2Fe(SO 4) 2 6H 2O(s)? 4.00 7.00 8.00 14.00 16. Which information can be gained from an infrared (IR) spectrum? Ionization energy of the most abundant element Number of different elements in the compound Bonds present in a molecule Molecular formula of the compound 17. What can be deduced from the following 1 H NMR spectrum? There is only one hydrogen atom in the molecule. There is only one hydrogen environment in the molecule. The molecule is a hydrocarbon. There is only one isotope in the element. 18. Which solution neutralizes 50.0 cm 3 of 0.120 mol dm 3 NaOH (aq)? 12.5 cm 3 of 0.080 mol dm 3 H 3PO 4 25.0 cm 3 of 0.120 mol dm 3 CH 3COOH 25.0 cm 3 of 0.120 mol dm 3 H 2SO 4 50.0 cm 3 of 0.060 mol dm 3 HNO 3 3
19. What is the pressure, in Pa, inside a 1.0 m 3 cylinder containing 10 kg of H 2 (g) at 25 ºC? R = 8.31 J K 1 mol 1 ; pv = nrt 20. A compound with M r = 102 contains 58.8 % carbon, 9.80 % hydrogen and 31 % oxygen by mass. What is its molecular formula? A r: C = 12.0; H = 1.0; O = 16.0 C 2H 14O 4 C 3H 4O 4 C 5H 10O 2 C 6H 14O 21. The graph shows values of ΔG for a reaction at different temperatures. Which statement is correct? The standard entropy change of the reaction is negative. The standard enthalpy change of the reaction is positive. At higher temperatures, the reaction becomes less spontaneous. The standard enthalpy change of the reaction is negative. 22. The molar mass of a gas, determined experimentally, is 32 g mol 1. Its literature molar mass is 40 g mol 1. What is the percentage error? 80% 25% 20% 8% 23. Which technique is used to determine the bond lengths and bond angles of a molecule? X-ray crystallography Infrared (IR) spectroscopy Mass spectroscopy 1 H NMR spectroscopy 4
24. Which equation represents sublimation? 2Al(s)+3I 2(g) 2AlI 3(s) HgCl 2(s) HgCl 2(g) I 2(g) I 2(s) CaCO 3(s)+2HCl(aq) CaCl 2(aq)+CO 2(g)+H 2O(l) 25. Graph 1 shows a plot of volume of CO 2(g) against time for the reaction of CaCO 3(s) with 1.00 moldm 3 HCl (aq). The acid is the limiting reagent and entirely covers the lumps of CaCO 3(s). Which set of conditions is most likely to give the data plotted in graph 2 when the same mass of CaCO 3(s) is reacted with the same volume of HCl(aq) at the same temperature? 26. Which volume, in cm 3, of 0.20 mol dm -3 NaOH (aq) is needed to neutralize 0.050 mol of H 2S(g)? H 2S(g) + 2NaOH(aq) Na 2S(aq) + 2H 2O(l) 0.25 0.50 250 500 27. For which compound is the empirical formula the same as the molecular formula? A r(h)=1; A r(c)=12; A r(o)=16 5
28. A measuring cylinder was used to obtain a known volume of a liquid. The volume was read from the top of the meniscus and the liquid completely emptied into a flask. The exact same process was then repeated. Which statement is correct about the overall described procedure and the volumes measured? There is a systematic error and the volumes measured are accurate. There is a random error and the volumes measured are accurate. There is a random error and the volumes measured are inaccurate. There is a systematic error and the volumes measured are inaccurate. 29. What is the index of hydrogen deficiency (IHD) for this molecule? 3 4 5 6 30. What is the relationship between the two variables sketched on the graph? y is proportional to x y is inversely proportional to x y is proportional to x y decreases exponentially with an increase in x 31. Which feature of a molecule can be determined from its 1 H NMR spectrum? Number of hydrogen environments Total mass of hydrogen atoms present Vibration frequency of C H bonds Ionization energy of a hydrogen atom 32. What is always correct about the molecular ion, M +, in a mass spectrum of a compound? The M + ion peak has the smallest m/z ratio in the mass spectrum. The m/z ratio of the M + ion peak gives the relative molecular mass of the molecule. The M + ion is the most stable fragment formed during electron bombardment. The M + ion peak has the greatest intensity in the mass spectrum. 6
33. In which mixture is NaOH the limiting reagent? 0.20mol NaOH + 0.10mol H 2SO 4 0.10mol NaOH + 0.10mol H 2SO 4 0.20mol NaOH + 0.10mol HNO 3 0.10mol NaOH + 0.10mol HNO 3 34. The complete combustion of 15.0cm 3 of a gaseous hydrocarbon X produces 60.0 cm 3 of carbon dioxide gas and 75.0 cm 3 of water vapour. What is the molecular formula of X? (All volumes are measured at the same temperature and pressure.) C 4H 6 C 4H 8 C 4H 10 C 6H 10 35. Which molecule has an index of hydrogen deficiency (IHD) = 1? C 6H 6 C 2Cl 2 C 4H 9N C 2H 6O 36. A student measured the change in mass on heating a sample of calcium carbonate, CaCO 3(s). What is the mass loss? Mass before heating: 2.347 g ± 0.001 Mass after heating: 2.001 g ± 0.001 0.346g ± 0.001 0.346g ± 0.002 0.35g ± 0.002 0.35g ± 0.001 37. Why do gases deviate from the ideal gas law at high pressures? Molecules have finite volume. Cohesive forces increase the volume from the ideal. Increasing pressure increases the temperature of the gas. Collisions between molecules occur more frequently as pressure increases. 38. 5.0mol of Fe 2O 3(s) and 6.0mol of CO(g) react according to the equation below. What is the limiting reactant and how many moles of the excess reactant remain unreacted? Fe 2O 3(s) + 3CO(g) 2Fe(s) + 3CO 2(g) 7
39. A measuring cylinder was used to obtain a known volume of a liquid. The volume was read from the top of the meniscus and the liquid completely emptied into a flask. The exact same process was then repeated. Which statement is correct about the overall described procedure and the volumes measured? There is a systematic error and the volumes measured are accurate. There is a random error and the volumes measured are accurate. There is a random error and the volumes measured are inaccurate. There is a systematic error and the volumes measured are inaccurate. 40. Combustion of ethanol takes place according to the following unbalanced equation. What is the mole ratio of ethanol to oxygen in the balanced equation? 1:1 2:1 1:3 2:7 41. The heat change in a neutralization reaction can be determined by mixing equal volumes of HCl(aq) and NaOH(aq) of the same concentration in a glass beaker. The maximum temperature change is recorded using an alcohol thermometer. What is the biggest source of error in this experiment? Heat absorbed by the glass thermometer Random error in the thermometer reading Heat loss to the surroundings Systematic error in measuring the volumes of HCl(aq) and NaOH(aq) using burettes 42. Which sample contains the largest amount, in mol, of oxygen atoms? 0.20 mol 0.30 mol 0.40 mol 0.80 mol 43. Which compound has the highest percentage of carbon by mass? 44. A student weighs a standard 70.00 g mass five times using the same balance. Each time she obtains a reading of 71.20 g. Which statement is correct about the precision and accuracy of the measurements? Precise and accurate Precise but inaccurate Accurate but not precise Neither accurate nor precise 45. Which solution contains the biggest amount, in mol, of chloride ions? of of of of 8
46. Ultraviolet radiation has a shorter wavelength than infrared radiation. How does the frequency and energy of ultraviolet radiation compare with infrared radiation? 47. What is the total number of protons and electrons in one mole of hydrogen gas? 2 4 48. A hydrocarbon contains 85.7 % carbon by mass. What is the empirical formula of the hydrocarbon? 49. What is the sum of all coefficients for the combustion of one mole of propane? 8 12 13 15 50. What is the best way to minimize the random uncertainty when titrating an acid of unknown strength against a standard solution of sodium hydroxide (ie one of known concentration)? First standardize the sodium hydroxide solution against a standard solution of a different acid. Use a ph meter rather than an indicator to determine the equivalence point. Keep your eye at the same height as the meniscus when reading the burette. Repeat the titration several times. 51. A gas with a molar mass ( ) of occupies a volume of at a pressure of and a temperature of 25 Which expression is correct for the calculation of the mass of the gas, in g? 9
52. Which expression gives the sum of all the coefficients for the general equation for the complete combustion of hydrocarbons? 53. 0.040 mol of is dissolved in water to give of aqueous solution. What is the concentration, in, of ammonium ions? 0.00040 0.0080 0.20 0.40 54. When sodium bromate(v),, is heated, it reacts according to the equation below. What amount, in mol, of produces of oxygen gas, measured at room temperature and pressure? (Molar volume of gas 0.017 0.067 0.10 0.15 at room temperature and pressure.) 55. Aluminium carbide reacts with water according to the equation below. What is the sum of all the coefficients when the equation is balanced? 13 14 19 20 56. In an experiment to determine a specific quantity, a student calculated that her experimental uncertainty was 0.9% and her experimental error was 3.5%. Which statement is correct? Only random uncertainties are present in this experiment. Both random uncertainties and systematic errors are present in this experiment. Repeats of this experiment would reduce the systematic errors. Repeats of this experiment would reduce both systematic errors and random uncertainties. Printed for Michael Power / St. Joseph High School International Baccalaureate Organization 2018 International Baccalaureate - Baccalauréat International - Bachillerato Internacional 10
IB Topics 1 & 11 Multiple Choice Practice - ANSWERS 1. D 2. D 3. D 4. C 5. B 6. B 7. A 8. B 9. D 10. D 11. C 12. B 13. B 14. C 15. B 16. C 17. B 18. C 19. D 20. C 21. B 22. C 23. A 24. B 25. C 26. D 27. D 28. D 29. D 30. C 31. A 32. B 33. B 34. C 35. C 36. B 37. A 38. B 39. D 40. C 41. C 42. A 43. D 44. B 45. B 46. A 47. D 48. B 49. C 50. D 51. A 52. C 53. D 54. B 55. D 56. B 11