Chemistry 20 Review Questions PDF

Chemistry 20 Review Questions 1. List properties that would help you identify each of the substances below. Also, predict and draw the VSEPR diagram for each molecular substance. a) NaCl b) H2O c) CH4 d) HCl e) H2 f) CH3OH g) Fe 2....

Chemistry 20 Review Questions 1. List properties that would help you identify each of the substances below. Also, predict and draw the VSEPR diagram for each molecular substance. a) NaCl b) H2O c) CH4 d) HCl e) H2 f) CH3OH g) Fe 2. At 22.5°C, a sample of nitrogen gas has a volume of 28.0L. To what temperature must this gas be heated to change the volume to 31.5L? 3. A solution of calcium chlorate is added to aqueous potassium sulphate. Give the non-ionic, total ionic, and net ionic equations. 4. A solution of lithium hydrogen sulphate turns blue litmus paper red. Give the modified Arrhenius equation to explain this evidence. 5. What mass of iron is required to completely react with 75.0 mL of 0.050 mol/L of aluminum nitrate? 6. For each of the following compounds, draw the Lewis diagram, predict and draw the VSEPR diagram and determine the polarity. a) PF3 b) C2H4 c) SF2 d) CH2Cl2 7. A piece of calcium is placed in a beaker containing 500 mL of hydroiodic acid. The initial mass of the calcium was 12.63 g; the final mass of calcium was 8.21 g. a) What is the concentration of the acid? b) Calculate the pH of the acid. c) How much volume of gas was produced at SATP conditions? 8. An observation balloon with a volume of 5.78 x 104 L is filled with helium at a temperature of 21.5 °C and a pressure of 89.7 kPa. The balloon rises until its volume is 7.12 x 104 L and the pressure is 74.0 kPa. Determine the temperature in °C of the helium at this altitude. 9. When 700 g of octane are burned, what mass of water vapour would be produced? 10. 12.5 g of sodium carbonate was added to 150 mL of 0.675 mol/L cobalt (III) chloride solution. What would be the mass of the precipitate produced? 11. You have a solution of strontium hydroxide with a concentration of 1.30 x 10-3 M. What is the pOH of the solution? 12. How many litres of 0.600 M solution would contain 131.6 g of lithium sulfate? 13. A 150.0 mL solution of potassium bromate has a concentration of 0.320 M. How much water must be added to change the concentration to 0.150 M? 14. Methane can be decomposed into solid carbon and hydrogen gas. What volume of methane gas at 110.0 kPa and 25.0 °C would be needed to produce 86.0 g of hydrogen gas? 15. For each of the following, draw a titration curve (include axis labels), choose a suitable indicator for each and explain your choice. a) weak acid with a strong base b) strong base with a strong acid c) strong base with a strong polyprotic acid 16. A 0.175 L sample of sodium carbonate has a sodium ion concentration of 0.500 M. What would be the mass of the solute? 17. A balloon contains 6.78 x 1021 molecules of helium at SATP. What would be the volume of this balloon? 18. What would be the density (in g/L) of 35.0 mL of butane (C4H10) at 35.0 °C and a pressure of 96.3 kPa? 19. A solution of perchloric acid of unknown concentration is titrated with a 5.25 x 10-2 M solution of strontium hydroxide. The following data was obtained: Titration of 25.0 mL of perchloric acid with strontium hydroxide Trial Initial volume (mL) Final volume (mL) 1 0.70 19.30 2 19.30 37.80 3 1.20 19.30 4 19.30 37.90 a) What is the concentration of perchloric acid? b) Determine the pH of the acid solution. 20. OMIT 21. The number of carbon atoms present in 0.062 mol acetic acid, CH3COOH(aq), is 22. Ammonia is produced from a reaction described by the equation 3 H2(g) + N2(g) 2 NH3(g). The chemical amount of hydrogen required to produce 12 mol of ammonia is 23. Determine the mass, in grams, of HCl needed to react completely with 12.8 g of aluminium, according to the following equation: 2 Al(s) + 6 HCl(aq) 2 AlCl3(aq) + 3 H2(g) 24. Zinc and sulfur react to form zinc sulfide, as shown in the following balanced chemical equation: Zn(s) + S8(s) ZnS(s) If 8.00 g of zinc and 8.00 g of sulfur are available for this reaction, the limiting reagent is 25. Consider the following balanced equation: Al(OH)3(s) + 3 HCl(aq) AlCl3(aq) + 3 H2O(l) Determine the mass of aluminium chloride, AlCl3, that is formed when 25.0 g of aluminium hydroxide reacts with 50.0 g of hydrochloric acid. 26. Cola soft drinks have a sucrose concentration of 11 g/100 mL. What mass of sucrose is present in a 355 mL can of cola? 27. 2.0 g of NaOH is added to 100 mL of water. What is the amount concentration of the solution? 28. Potassium chlorate decomposes to form potassium chloride and oxygen gas. What mass of solid potassium chlorate is required to form 120.0 g of potassium chloride? 29. Iron(III) oxide can be formed by combining iron and oxygen gas. Determine the mass of iron(III) oxide produced when 48.2 g of oxygen gas reacts with excess iron. 30. Describe and provide an example of an isotope. 31. According to Bohr’s atomic model, how many electrons can be in each of the first three energy levels in order for the atom to be stable? 32. An example of a chemical change process in a chemical industry is a. crude oil fractionally distilled in an oil refinery b. recovery of salt by evaporation of water from a salt lake c. lime added to water to produce calcium hydroxide (slaked lime) d. nitrogen condensed from air for use in the Haber process 33. Predict the products for the following chemical reaction: A sulfuric acid spill is neutralized by a sodium hydroxide solution. 34. Predict the products and write a balanced chemical equation for the following chemical reaction: Hydrochloric acid is neutralized by an aluminum hydroxide suspension. 35. Explain why methanol has a higher boiling point than methane 36. Table 3.2 Molecular Compounds and their Shapes Molecular compound Shape H2S(g) angular (V-shaped) II PH3(g) trigonal pyramidal III C2H6(g) tetrahedral IV C2H4(g) trigonal planar Use Table 3.2 to answer the following question. The substance with the same molecular shape as phosphorus trihydride, PH3(g), is A. H2O B. NH3 C. N2H4 D. P2O5 37. Write a sentence to describe the theoretical structure of ionic compounds. 38. Briefly describe how polar covalent bonds occur. 39. Draw Lewis structures for carbon dioxide and carbon monoxide. 40. Draw Lewis symbols for oxygen, sodium, boron, and neon. 41. Use Lewis formulas to explain why oxygen and fluorine are diatomic elements. 42. Use a Lewis formula and VSEPR to explain why ammonia is a polar molecule. 43. Why are the melting and boiling points of water, H2O(l), much higher than the melting and boiling points of hydrogen sulfide, H2S(g)? Use intermolecular forces, molecular shape, and other relevant information to explain your answer. 44. Determine the volume occupied by 3.45 g of carbon dioxide gas at STP. 45. Predict the reading on the pressure gauge if a canister holds 0.155 mol of N2 at 23 °C and has a volume of 8.95 L. 46. A balloon is brought to the top of Mt. Logan, where it occupies a volume of 775 mL at a temperature of –28 °C and a pressure of 92.5 kPa. What is the pressure at the bottom of the mountain if the same balloon has a volume of 825 mL at a temperature of 15 °C? 47. The constant bombardment on the walls of a rigid container by gas molecules can be used to determine what characteristic of the gas? 48. Which of the following statements are true? (i) As temperature decreases, molecules move more rapidly. (ii) If the volume is constant, an increase in pressure may be a result of an increase in the number of gas molecules in the container. (iii) The molecules of a gas are in constant, random, and nonlinear motion. (iv) The volume of a given mass of gas varies directly with its absolute temperature when the pressure remains constant. A. (iii) and (iv) B. (ii) and (iv) C. (i) and (iii) D. (i) and (ii) 49. Which of the following statements is not true? A. Gases can be expanded without limit. B. The molar mass of a gaseous substance is a constant quantity. C. The density of a gas is constant as long as its temperature remains constant. D. Gases diffuse into one another and mix thoroughly as soon as they are placed in the same flask. 50. Which of the following is not an observed property of all gases? A. Gases are compressible and can liquefy under pressure. B. Gases have variable shape and volume. C. Gases expand to fill their containers. D. Gases have a density greater than 1.00 g/mol 51. Explain dynamic equilibrium in saturated solutions 52. T.S.P. is an all-purpose cleaner that can be used to clean driveways. What volume of solution would you get if you dissolved 150.0 g of sodium phosphate in water to produce a 0.23 mol/L solution? 53. Concentrated hydrogen peroxide in high school labs is 30% W/V H2O2 dissolved in water. Calculate the mass of pure H2O2 dissolved in a 450 mL bottle? 54. A sports drink contains 50 mg of sodium ions and 55 mg of potassium ions per 400 mL serving. Calculate the concentration of the sodium and potassium ions, in ppm. 55. Standard solutions of sodium oxalate, , are required for certain types of chemical analyses. If 8.5 g of sodium oxalate is dissolved in 500 mL of distilled water, calculate the concentration of the sodium ion and the concentration of the oxalate ion, C2O42-(aq), dissolved in this solution. 56. As temperature increases, the solubility of NaNO3 in water increases. Give a theoretical reason for this observation. 57. Describe the difference between dilute and concentrated solutions. 58. Differentiate between the terms saturated and unsaturated. 59. A sample of well water is thought to contain a high concentration of iron. What solution could you use to obtain a positive precipitate test for the dissolved iron? 60. Coffee has a pH of 5.0 and grapefruit juice has a pH of 3.0. Calculate the hydronium ion concentration for both drinks and determine how many times more acidic the juice is than the coffee. 61. Write two ionization equations and % ionization to illustrate that hydrochloric acid has high conductivity and hydrofluoric acid has low conductivity. 62. A 0.1 mol/L solution of nitric acid has a pH of about 1 and a 0.1 mol/L solution of acetic acid has a pH of about 3. (a) Account theoretically for this difference in pH. (b) Explain which acid is more acidic and by how much. 63. Show all the steps involved in the successive reactions of the polyprotic acid H3PO3. Be sure to show H2O in each of the steps. 64. Using only indicators, outline how you could confirm that the pH of a solution is 7.1 65. What mass of CO2(g) can be produced at a temperature of 1500 °C and an atmospheric pressure of 92.5 kPa if 15.5 L of C2H2(g) is burned at STP conditions according to the following equation? 66. A quality-control technician is testing the concentration of muriatic acid (hydrochloric acid) to check that the concentration is within certain limits. Calculate the concentration of the hydrochloric acid if a 15.00 mL sample, diluted by factor of 10, is titrated with standard sodium carbonate solution. The titration required 10.00 mL of 0.250 mol/L sodium carbonate to neutralize the acid. 67. 500 g of copper metal reacts with 2.5 L of 3.0 mol/L nitric acid solution. The unbalanced equation for the reaction is. Calculate how much of the copper metal remains after the reaction is complete. 68. Consider the following balanced equation: 4 ZnS(s) + 6 O2(g) 4 ZnO(s) + 4 SO2(g) Determine the mass of zinc oxide produced when 16.7 g of zinc sulfide is combined with 6.70 g of oxygen gas. Calculate the chemical amount of oxygen gas needed to react completely with 16.7 g of zinc sulfide. 69. Sodium chloride is produced when sodium metal combines with chlorine gas as shown in the following balanced equation: 2 Na(s) + Cl2(g) 2 NaCl(s) In an experiment, 36.9 g of sodium chloride is produced when 15.9 g of sodium and 27.4 g of chlorine are combined. Determine the percent yield of the product. Calculate the chemical amount of chlorine needed to react completely with 15.9 g of Na. 70. A student mixed 100.0 mL of a 0.100 mol/L solution of barium chloride with 100.0 mL of a 0.100 mol/L solution of iron(III) sulfate. The barium sulfate precipitate was filtered, dried, and measured to have a mass of 2.0 g. Calculate the percent yield of the barium sulfate. 71. Sketch the pH curve for a weak polyprotic base titrated with a strong acid