General Chemistry The Essentials Concepts

General Chemistry The Essentials Concepts 1. A tentative explanation for a set of observations that can be tested by further experimentation is referred to as A) a hypothesis. B) a law. C) a theory. D) none of the above. Ans:  A 2. A concise verbal or mathematical statement of a relationship between phenomena that is always the same under the same conditions is referred to as A) a hypothesis. B) a law. C) a theory. D) none of the above. Ans:  B 3. A unifying principle that explains a body of facts and relations is referred to as A) a hypothesis. B) a law. C) a theory. D) none of the above. Ans:  C 4. Complete the following sentence. A hypothesis is A) a tentative explanation for a set of observations that can be tested by further experimentation. B) a statement describing a relationship between phenomena that is always the same under the same conditions. C) a unifying principle that explains a body of facts and relations. D) a model used to visualize the invisible. Ans:  A 5. Complete the following sentence. A scientific law is A) a tentative explanation for a set of observations that can be tested by further experimentation. B) a statement describing a relationship between phenomena that is always the same under the same conditions. C) a unifying principle that explains a body of facts and relations. D) a model used to visualize the invisible. Ans:  B 6. Complete the following sentence. A theory is A) a tentative explanation for a set of observations that can be tested by further experimentation. B) a statement describing a relationship between phenomena that is always the same under the same conditions. C) a unifying principle that explains a body of facts and relations. D) a model used to visualize the invisible. Ans:  C 7. Choose the response that includes all the items listed below that are pure substances. i. orange juice ii. steam iii. ocean water iv. oxygen v. vegetable soup A) i, iii, v B) ii, iv C) i, iii, iv D) iv only E) all of them are pure Ans:  B 8. Which of the following is an example of a physical property? A) corrosiveness of sulfuric acid B) toxicity of cyanide C) flammability of gasoline D) neutralization of stomach acid with an antacid E) lead becomes a liquid when heated to 601?C Ans:  E 9. Which one of the following is an example of a physical property? A) dynamite explodes D) ice floats on top of liquid water B) meat rots if it is not refrigerated E) a silver platter tarnishes C) gasoline burns Ans:  D 10. Which one of the following represents a physical change? A) water, when heated to 100?C, forms steam B) bleach turns hair yellow C) sugar, when heated, becomes brown D) milk turns sour E) apples, when exposed to air, turn brown Ans:  A 11. All of the following are properties of sodium. Which one is a physical property of sodium? A) It is a surface turns black when first exposed to air. B) It is a solid at 25?C and changes to a liquid when heated to 98?C. C) When placed in water it sizzles and a gas is formed. D) When placed in contact with chlorine it forms a compound that melts at 801?C. E) Sodium is never found as the pure metal in nature. Ans:  B 12. All of the following are properties of tin. Which one is a chemical property of tin? A) Tin can be hammered into a thin sheet. B) At –40?C a sheet of tin crumbles to a gray powder. C) Tin melts at 231.9?C. D) When a bar of tin is bent, it emits an audible “cry”. E) Tin erodes when added to hydrochloric acid, and a clear gas forms. Ans:  E 13. Which one of the following represents a chemical change? A) boiling water to form steam B) burning a piece of coal C) heating lead until it melts D) mixing iron filings and sand at room temperature E) breaking glass Ans:  B 14. Which of the following does not represent a chemical change? A) a freshly cut apple turns brown B) milk turns sour on standing at room temperature C) when cooled to 0?C, liquid water becomes ice D) frying an egg E) fermentation of sugar to alcohol Ans:  C 15. The SI prefixes nano and deci represent, respectively: A) 10– 9 and 10– 6. D) 109 and 10– 6. B) 106 and 10– 3. E) 10– 9 and 10– 1. C) 103 and 10– 3. Ans:  E 16. The SI prefixes milli and mega represent, respectively: A) 106 and 10– 6. D) 10– 3 and 109. B) 10– 3 and 106. E) 10– 6 and 10– 3. C) 103 and 10– 6. Ans:  B 17. The SI prefixes kilo and centi represent, respectively: A) 103 and 10– 2. D) 10– 6 and 102. B) 106 and 10– 1. E) 102 and 10– 3. C) 10– 3 and 10– 2. Ans:  A 18. A nanometer corresponds to: A) 10– 2 meters. D) 10– 9 meters. B) 10– 3 meters. E) 10– 12 meters. C) 10– 6 meters. Ans:  D 19. A microliter corresponds to: A) 10– 2 liters. B) 10– 3 liters. C) 10– 6 liters. D) 10– 9 liters. E) 10– 12 liters. Ans:  C 20. 6.0 km is how many micrometers? A) 6.0 ? 106 µm D) 1.7 ? 10– 4 µm B) 1.7 ? 10– 7 µm E) 6.0 ? 103 µm C) 6.0 ? 109 µm Ans:  C 21. 2.4 km is how many millimeters? A) 2,400 mm D) 2.4 ? 106 mm B) 2.4 ? 104 mm E) 2.4 ? 10– 5 mm C) 2.4 ? 105 mm Ans:  D 22. How many milliliters is 0.005 L? A) 0.5 mL B) 5 mL C) 0.50 mL D) 0.000005 mL E) 200 mL Ans:  B 23. Express 7,500 nm as picometers. A) 7.50 pm B) 75.0 pm C) 750 pm D) 7.5 ? 106 pm E) 7.5 ? 1012 pm Ans:  D 24. The diameter of Earth is 12.7 Mm. Express this diameter in centimeters. A) 1.27 ? 105 cm D) 1.27 ? 108 cm B) 1.27 ? 106 cm E) 1.27 ? 109 cm C) 1.27 ? 107 cm Ans:  E 25. In 1828, the diameter of the U.S. dime was changed to approximately 18 mm. What is this diameter when expressed in nanometers? A) 1.8 ? 109 nm D) 1.8 ? 10– 5 nm B) 1.8 ? 107 nm E) 1.8 ? 10– 10 nm C) 1.8 ? 101 nm Ans:  B 26. Which of the following represents the largest mass? A) 2.0 ? 102 mg D) 2.0 ? 102 cg B) 0.0010 kg E) 10.0 dg C) 1.0 ? 105 ng Ans:  D 27. Lead melts at 601.0?C. What temperature is this in oF? A) 302?F B) 365?F C) 1,050?F D) 1,082?F E) 1,114?F Ans:  E 28. The element gallium melts at 29.8?C. What temperature is this in ?F? A) –54.1?F B) –7.8?F C) +13.5?F D) +51.3?F E) +85.6?F Ans:  E 29. Many home freezers maintain a temperature of 0?F. Express this temperature in ?C. A) –32?C B) –18?C C) 0?C D) 18?C E) 57.6?C Ans:  B 30. The highest temperature ever recorded in Phoenix, Arizona, was 122?F. Express this temperature in ?C. A) 50.0?C B) 64.4?C C) 67.8?C D) 162.0?C E) 219.6?C Ans:  A 31. Dry ice (carbon dioxide) changes from a solid to a gas at –78.5?C. What is this temperature in ?F? A) –173?F B) –12.6?F C) –109?F D) –75.6?F E) none of them are within 2?F of the right answer Ans:  C 32. Liquid nitrogen boils at –195.8?C. Express the boiling point of liquid nitrogen in kelvin. A) –469.0 K B) –77.4 K C) all temperatures are 0 K on the Kelvin scale D) 77.4 K E) 469.0 K Ans:  D 33. Liquid nitrogen boils at –195.8?C. Express the boiling point of liquid nitrogen in ?F. A) –384.4?F B) –352.4?F C) –320.4?F D) –140.8?F E) –76.8?F Ans:  C 34. Express the number 26.7 in scientific notation. A) 2.67 ? 10–2 B) 2.67 ? 10–1 C) 2.67 ? 101 D) 2.67 ? 102 E) 26.7 is already written in scientific notation Ans:  C 35. Express the number 0.000053 in scientific notation. A) 5.3 ??10-2 B) 5.3 ? 10-3 C) 5.3 ? 10-4 D) 5.3 ? 10-5 E) 5.3 ? 10-6 Ans:  D 36. The number 1.050 ? 109 has how many significant figures? A) 2 B) 3 C) 4 D) 9 E) 13 Ans:  C 37. How many significant figures are there in 1.3070 g? A) 6 B) 5 C) 4 D) 3 E) 2 Ans:  B 38. Express the fraction 1/23 as a decimal to 4 significant figures. A) 0.0434 B) 0.0435 C) 0.04347 D) 0.04348 E) 0.04350 Ans:  D 39. Express the fraction 1/51 in scientific notation to 3 significant figures. A) 2 ? 10–2.00 D) 1.97 ? 10–2 B) 2.0 ? 10–2.00 E) 2.00 ? 10–2 C) 1.96 ? 10–2 Ans:  C 40. After carrying out the following operations, how many significant figures are appropriate to show in the result? (13.7 + 0.027) ? 8.221 A) 1 B) 2 C) 3 D) 4 E) 5 Ans:  C 41. How many significant figures does the result of the following operation contain? 8.52010 ? 7.9 A) 2 B) 3 C) 4 D) 5 E) 6 Ans:  A 42. How many significant figures does the result of the following sum contain? 8.5201 + 1.93 A) 1 B) 2 C) 3 D) 4 E) 5 Ans:  D 43. How many significant figures does the result of the following sum contain? 8.520 + 2.7 A) 1 B) 2 C) 3 D) 4 E) 5 Ans:  C 44. How many significant figures does the difference 218.7201 – 218.63 contain? A) 1 B) 2 C) 3 D) 5 E) 7 Ans:  A 45. Do the indicated arithmetic and give the answer to the correct number of significant figures. (1.5 ? 10–4 ? 61.3) + 2.01 = A) 2.0192 B) 2.0 C) 2.019 D) 2.02 E) 2.019195 Ans:  D 46. When 7.02oC is converted to the Fahrenheit scale, how many significant figures are there in the ?F result? A) 1 B) 2 C) 3 D) 4 E) 5 Ans:  C 47. How many cubic inches are in 1.00 liter? A) 61.0 in3 B) 155 in3 C) 394 in3 D) 1.64 ? 104 in3 E) none of them Ans:  A 48. Convert 500. milliliters to quarts. (1L = 1.06 qt) A) 1.88 qt B) 0.472 qt C) 0.528 qt D) 4.72 ? 105 qt E) 5.28 ? 105 qt Ans:  C 49. A US barrel is 4.21 cubic feet. Express this volume in liters. A) 3.99 ? 10–5 L B) 1.99 ? 10–2 L C) 19.9 L D) 105 L E) 119 L Ans:  E 50. A barrel of oil contains 42.0 gallons. How many liters is this? (1L = 1.06 qt) A) 9.9 L B) 11 L C) 142 L D) 158 L E) 178 L Ans:  D 51. The average distance from Earth to the sun is 9.3 ? 107 miles. How many kilometers is this? A) 1.5 ? 108 km D) 1.7 ? 10 – 8 km B) 1.5 ? 105 km E) 1.5 ? 1011 km C) 5.6 ? 107 km Ans:  A 52. What is the area, in square centimeters, of an 8.5 inch by 11 inch sheet of paper? A) 94 cm2 B) 240 cm2 C) 420 cm2 D) 6.0 ? 102 cm2 E) 1.2 ? 104 cm2 Ans:  D 53. Suppose a house has a floor area of 2,250 square feet. What is this area in units of square centimeters? A) 2.42 cm2 D) 6.86 ? 104 cm2 B) 2.09 ? 106 cm2 E) 101 cm2 C) 5.02 ? 104 cm2 Ans:  B 54. What is the volume, in cubic inches, of a brick that is 4.0 in ? 2.7 in ? 8.0 in? A) 15 in3 B) 51 in3 C) 78 in3 D) 87 in3 E) 150 in3 Ans:  D 55. What is the volume, in cubic centimeters, of a brick that is 4.0 in ? 2.7 in ? 8.0 in? A) 5.3 cm3 B) 53 cm3 C) 87 cm3 D) 4.8 ? 102 cm3 E) 1.4 ? 103 cm3 Ans:  E 56. How many square kilometers are equivalent to 28.5 cm2? A) 2.85 ? 10–9 km2 D) 2.85 ? 10–4 km2 B) 2.85 ? 10–6 km2 E) none of these C) 285 km2 Ans:  A 57. How many cubic centimeters are there in exactly one cubic meter? A) 1 ? 10–6 cm3 D) 1 ? 104 cm3 B) 1 ? 10–3 cm3 E) 1 ? 106 cm3 C) 1 ? 10–2 cm3 Ans:  E 58. If a car has an EPA mileage rating of 30 miles per gallon, what is this rating in kilometers per liter? (1 L = 1.06 qt) A) 200 km/L B) 180 km/L C) 70 km/L D) 13 km/L E) 11 km/L Ans:  D 59. If the price of gasoline is $2.99 per U.S. gallon, what is the cost per liter? (1 L = 1.06 qt) A) $0.30/L B) $0.79/L C) $1.27/L D) $2.99/L E) $12.66/L Ans:  B 60. An aluminum beverage can contains 12.0 fluid ounces of liquid. Express this volume in liters. (1 fl oz = 29.6 mL) A) 4.07 ? 10-2 L B) 0.355 L C) 0.407 L D) 2.46 L E) 3.55 ? 102 L Ans:  B 61. 157.2 ? 106 troy oz of silver were used in the United States in 1980. How many gigagrams is this? (1 troy oz = 31.1 g) A) 4.89 ? 109 Gg D) 3.12 Gg B) 4.89 Gg E) 5.05 ? 10 – 3 Gg C) 5.05 ? 10 – 9 Gg Ans:  B 62. A piece of metal with a mass of 611 g is placed into a graduated cylinder that contains 25.1 mL of water, raising the water level to 56.7 mL. What is the density of the metal? A) 2.70 g/cm3 B) 7.13 g/cm3 C) 8.96 g/cm3 D) 10.5 g/cm3 E) 19.3 g/cm3 Ans:  E 63. A piece of a metal alloy with a mass of 114 g was placed into a graduated cylinder that contained 25.0 mL of water, raising the water level to 42.5 mL. What is the density of the metal? A) 0.154 g/cm3 D) 6.51 g/cm3 B) 0.592 g/cm3 E) 7.25 g/cm3 C) 2.68 g/cm3 Ans:  D 64. A block of iron has a mass of 826 g. What is the mass of a block of magnesium that has the same volume as the block of iron? The following densities at 25?C are provided: magnesium, 1.7 g/cm3 ; graphite, 1.8 g/cm3 ; iron, 7.9 g/cm3. A) 1,400 g B) 3,800 g C) 830 g D) 180 g E) none of them are within 10 g of the right answer. Ans:  D 65. A block of iron has a mass of 483 g. What is the mass of a block of graphite that has the same volume as the block of iron? The following densities at 25?C are provided: magnesium, 1.7 g/cm3 ; graphite, 1.8 g/cm3 ; iron, 7.9 g/cm3. A) 110 g B) 2120 g C) 6870 g D) 34 g E) none of them are within 10 g of the right answer. Ans:  A 66. Calculate the mass of the air contained in a room that measures 2.50 m ? 5.50 m ? 3.00 m (density of air = 1.29 g/dm3 at 25?C). A) 3.13 ? 10 –5 g B) 32.0 kg C) 53.2 kg D) 53.2 g E) None of the above. Ans:  C 67. The density of lead is 11.4 g/cm3 at 25?C. Calculate the volume occupied by 25.0 g of lead. A) 2.19 cm3 B) 0.456 cm3 C) 285 cm3 D) 1.24 cm3 E) 6.05 cm3 Ans:  A 68. Iron has a density of 7.86 g/cm3. The volume occupied by 55.85 g of iron is A) 0.141 cm3. D) 439 cm3. B) 7.11 cm3. E) None of the above. C) 2.8 cm3. Ans:  B 69. Iridium is essentially tied with osmium for the distinction of being called the “densest element” with a density of 22.5 g/cm3. What would be the mass in pounds of a 1.0 ft ? 1.0 ft ? 1.0 ft cube of iridium? (1 lb = 453.6 g) A) 1.5 lb B) 5.2 lb C) 6.20 lb D) 1.4 ? 10 3 lb E) 6.4 ? 10 5 lb Ans:  D 70. Bromine is a red liquid at 25?C. Its density is 3.12 g/cm3. What is the volume of 28.1 g of liquid bromine? A) 87.7 cm3 D) 28.1 cm3 B) 0.111 cm3 E) None of the above. C) 9.01 cm3 Ans:  C 71. The Hope diamond weighs 44.0 carats. Determine the volume occupied by the diamond, given that its density is 3.5 g/cm3 at 20?C, and that 1 carat = 0.200 g. A) 2.5 cm3 B) 0.40 cm3 C) 0.016 cm3 D) 63 cm3 E) 150 cm3 Ans:  A 72. What is the volume of a 2.5 g block of metal if its density is 4.75 g/cm3? A) 0.53 cm3 B) 1.9 cm3 C) 2.5 cm3 D) 4.75 cm3 E) 11.9 cm3 Ans:  A 73. The density of mercury is 13.6 g/cm3. What is the mass in pounds of 1.0 gallons of mercury? (1 lb = 453.6 g; 1 gal = 3.785 L) A) 0.11 lb B) 30. lb C) 51 lb D) 83 lb E) 110 lb Ans:  E 74. The density of mercury is 13.6 g/cm3. What volume (in quarts) is occupied by 100. g of Hg? (1 L = 1.06 qt) A) 144 qt B) 7.35 qt C) 7.79 qt D) 7.79 ? 10 – 3 qt E) 1.44 ? 10 – 4 qt Ans:  D 75. The "escape velocity" from Earth (the speed required to escape Earth's gravity) is 2.5 ? 104 miles per hour. What is this speed in m/s? (1 mile = 1609 m) A) 4.2 ? 10–3 m/s D) 1.1 ? 104 m/s B) 6.9 m/s E) 4.0 ? 107 m/s C) 4.2 ? 102 m/s Ans:  D 76. Which of the following speeds is the greatest? (1 mile = 1609 m) A) 40 mi/h D) 0.74 km/min B) 2.0 ? 105 mm/min E) 400 m/min C) 40 km/h Ans:  A 77. Iron has a density of 7.87 g/cm3. What mass of iron would be required to cover a football playing surface of 120 yds ??60 yds to a depth of 1.0 mm? (1 inch = 2.54 cm; 1 lb = 453.6 g) A) 6.4 ? 103 lb D) 4.7 ? 107 lb B) 6.4 ? 104 lb E) 4.7 ? 108 lb C) 1.0 ? 105 lb Ans:  C 78. Americans combined drive about 4.0?109 miles per day and their vehicles get an average of 20 miles per gallon of fuel used. For each 1 kg of gasoline that is burned, about 3.0 kg of carbon dioxide are produced. How many kilograms of CO2 are emitted into the atmosphere each day by cars in the U.S.? One gallon of gas weighs about 3.5 kg. A) 2.1 ? 109 kg D) 93 kg B) 8.4 ? 1011 kg E) none of these C) 1.7 ? 108 kg Ans:  A 79. How many cubic centimeters of an ore containing only 0.22% gold (by mass) must be processed to obtain $100 worth of gold? The density of the ore is 8.0 g/cm3 and the price of gold is $818 per troy ounce. (14.6 troy oz = 1.0 ordinary pound, called an avoirdupois pound; 1 lb = 454 g) A) 0.48 cm3 D) 1.7 ? 103 cm3 B) 220 cm3 E) 1.8 ? 104 cm3 C) 1.4 ? 103 cm3 Ans:  B 80. Radio waves travel at the speed of light, which is 3.00 ? 108 m/s. How many minutes does it take for a radio message to reach Earth from Saturn if Saturn is 7.9 ? 108 km from Earth? A) 4.4 ? 10 –2 min D) 44 min B) 1.6 ? 105 min E) 2.6 min C) 4.0 ? 1015 min Ans:  D 81. Radio waves travel at the speed of light, which is 3.00 ? 108 m/s. How many kilometers will radio messages travel in exactly one year? A) 9.46 ? 1015 km D) 9.46 ? 1012 km B) 7.30 ? 108 km E) 3.33 ? 10 – 3 km C) 7.10 ? 1010 km Ans:  D 82. The city of Los Angeles is now approximately 2400 miles south of Alaska. It is moving slowly northward as the San Andreas fault slides along. If Los Angeles is to arrive near Anchorage, Alaska, in 76 million years, at what average rate will it have to move in mm per month? A) 2.0 ? 10 – 10 mm/mo. D) 9.5 mm/mo. B) 6.6 ? 10 – 6 mm/mo. E) 51 mm/mo. C) 4.2 mm/mo. Ans:  C 83. The recommended daily allowance (RDA) of calcium is 1.2 g. Calcium carbonate contains 12.0% calcium by mass. How many grams of calcium carbonate are needed to provide the RDA of calcium? A) 0.10 g B) 0.14 g C) 1.2 g D) 10 g E) 14 g Ans:  D 84. The radius of the Earth is approximately 6370 km. If one could dig down straight towards the center of the Earth, one would find that the outermost 2890 km (the crust and the mantle) has an average density of about 4.5 g/cm3. Farther down is the core. If the average density of the Earth is 5.5 g/cm3, what is the average density of the Earth's core? (Recall that the volume of a sphere is given by V = (4/3)?r3.) A) 11. g/cm3 D) 1.9 g/cm3 B) 57. g/cm3 E) not enough data is provided C) 6.2 g/cm3 Ans:  A 85. The radius of the Earth is approximately 6370 km. If one could dig down straight towards the center of the Earth, one would find that the innermost 3480 km (the core) has an average density of about 11. g/cm3. Above that are the mantle and crust. If the average density of the Earth is 5.5 g/cm3, what is the average density of the Earth's mantle and crust? (Recall that the volume of a sphere is given by V = (4/3)?r3.) A) 57. g/cm3 D) 5.3 g/cm3 B) 4.5 g/cm3 E) not enough data is provided C) 8.7 g/cm3 Ans:  B 86. An object sinks when placed in water if the mass of the object is greater than the mass of the water that the object displaces. Which of the following objects will sink when dropped into a bucket of water? (Given: density of water = 1.00 g/cm3) A) a cube of aluminum (density = 2.702 g/cm3) B) a diamond (density = 3.51 g/cm3) C) a chunk of dry ice (density = 1.56 g/cm3) D) a chunk of sodium (density = 0.91 g/cm3) E) a sphere of magnesium (density = 1.74 g/cm3) Ans:  D 87. An object will float at the surface of a liquid if the mass of the object is less than the mass of the liquid that it displaces. A spherical vessel (diameter = 2.00 cm) when empty has a mass of 2.00 g. What is the greatest volume of water that can be placed in the vessel and still have the vessel float at the surface of water? (Given: density of water = 1.00 g/cm3) A) 2.00 mL B) 31.5 mL C) 2.19 mL D) 4.19 mL E) the vessel will not float even when empty Ans:  C 88. An object will float at the surface of a liquid if the mass of the object is less than the mass of the liquid that it displaces. A spherical vessel (diameter = 5.00 cm) when empty has a mass of 12.00 g. What is the greatest volume of water that can be placed in the vessel and still have the vessel float at the surface of benzene? (Given: density of water = 1.00 g/cm3; density of benzene = 0.879 g/cm3) A) 45.5 mL B) 448 mL C) 53.4 mL D) 57.5 mL E) 65.4 mL Ans:  A 89. One of the common intravenous fluids, called physiological saline, is a homogeneous mixture of NaCl in water. In this mixture, 0.89% of the mass is contributed by the NaCl. What mass of NaCl is found in 450. mL of physiological saline? (Given: density of physiological saline = 1.005 g/cm3) A) 2.0 g B) 4.0 g C) 5.1 g D) 508 g E) 400 g Ans:  B 90. A special flask used in the determination of densities, called a pycnometer, has a mass of 16.3179 g when empty, and it has a mass of 48.0250 g when filled with water at 20.0?C. When this same pycnometer is filled with ethyl alcohol at 20.0?C, it is found to have a mass of 41.3934 g. Find the density of ethyl alcohol at 20.0?C. (Given: at 20.0?C, the density of water is 0.9982 g/mL) A) 0.7894 g/mL D) 1.303 g/mL B) 0.7923 g/mL E) 0.7674 g/mL C) 0.7908 g/mL Ans:  A 91. A particular flask has a mass of 17.4916 g when empty. When filled with ordinary water at 20.0°C (density = 0.9982 g/mL), the mass of the flask is now 43.9616 g. The density of so-called “heavy water” at 20.0°C is 1.1053 g/mL. What will the mass of the flask be when filled with heavy water at 20.0°C? A) 29.2573 g B) 46.8016 g C) 46.7489 g D) 29.3100 g E) 43.9140 g Ans:  B 92. Define matter. Ans: Matter is anything that occupies space and has mass. 93. What are the three states of matter? Ans: Solid, liquid, and gas Section:  1.5 94. What are the common names for the three states of the compound water? Ans: Ice, water, and steam Section:  1.5 95. Define pure substance. Ans: Something that has a definite composition 96. Give three examples of pure substances. Ans: (Answers will vary.) Gold, sugar, oxygen, argon, water, methane 97. Define mixture. Ans: A mixture is a combination of two or more substances in which the substances retain their distinct identities. 98. Name two types of mixtures. Ans: Homogeneous mixture and heterogeneous mixture 99. Give three examples of mixtures. Ans: (Answers will vary.) Air, gasoline, sea water, salt and sand, iron filings and sand 100. Define element. Ans: An element is a substance that cannot be separated into simpler substances by chemical means. 101. Define compound. Ans: A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions. 102. Give examples of three physical properties. Ans: (Answers will vary.) Melting point, boiling point, density, color 103. Give an example of an extensive property. Ans: (Answers will vary.) Mass, length, and volume 104. Give an example of an intensive property. Ans: (Answers will vary.) Temperature, density, melting point, boiling point 105. Identify the following as a physical or chemical change: Bacteria convert milk to yogurt. Ans: Chemical 106. Identify the following as a physical or chemical change: Water is broken down into hydrogen and oxygen. Ans: Chemical 107. Identify the following as a physical or chemical change: Formation of snowflakes. Ans: Physical 108. Identify the following as a physical or chemical change: Rusting of a piece of iron. Ans: Chemical 109. Identify the following as a physical or chemical change: Ripening of fruit. Ans: Chemical 110. Identify the following as a physical or chemical change: Fashioning a table leg from a piece of wood. Ans: Physical 111. Identify the following as a physical or chemical change: Fermenting grapes. Ans: Chemical 112. Classify the following as a physical or chemical change: Antifreeze boils out of a radiator. Ans: Physical 113. Classify the following as a physical or chemical change: Food spoils. Ans: Chemical 114. Classify the following as a physical or chemical change: Alcohol evaporates. Ans: Physical 115. Classify the following as either a physical or a chemical property: Ice melts at 0oC. Ans: Physical 116. Classify the following as either a physical or a chemical property: Newspaper burns. Ans: Chemical 117. Classify the following as either a physical or a chemical property: The vitamin content of foods in contact with air falls. Ans: Chemical 118. Classify the following as a pure substance or a mixture: Ice cream. Ans: Mixture 119. Classify the following as a pure substance or a mixture: Bread. Ans: Mixture 120. Classify the following as a pure substance or a mixture: Seven-Up®. Ans: Mixture 121. Classify the following as an element, a compound, or a mixture: Air. Ans: Mixture 122. Classify the following as an element, a compound, or a mixture: Table salt (non-iodized). Ans: Compound 123. Classify the following as an element, a compound, or a mixture: Chicken broth. Ans: Mixture 124. Classify the following as an element, a compound, or a mixture: Oxygen gas. Ans: Element 125. Classify the following as a mixture, a compound, or an element: Brewed coffee, ready to drink. Ans: Mixture 126. Classify the following as a mixture, a compound, or an element: Sugar to put in a cup of coffee. Ans: Compound 127. Classify the following as a mixture, a compound, or an element: Orange juice. Ans: Mixture 128. A pure yellow crystalline substance, when heated in a vacuum, releases a greenish gas and a red powder. Is the original yellow crystalline substance a compound or element? Ans: Compound 129. In the process of fixing breakfast you: 1. break open the egg 2. fry it 3. cut the fried egg into pieces 4. toast a slice of bread 5. cut the toast in half Which of these are chemical processes? Ans: 2 (frying the egg) and 4 (toasting the bread) 130. An organic liquid has a density of 0.8 g/cm3. What is the mass of a 42.0 mL sample of this liquid? Ans: 30 g 131. What is the density of copper if 11.8 cm3 of copper has a mass of 105.2 g? Ans: 8.92 g/cm3 132. An automobile engine has a piston displacement of 1,600 cm3. Express this volume in liters. Ans: 1.6 L 133. An automobile engine has a piston displacement of 1,600 cm3. Express this volume in cubic inches. (1 in = 2.54 cm) Ans: 98 in3 134. An investor paid market price for a chunk of gold that he was told was pure. The gold bar had a mass of 440 g, but was slightly irregular so an exact volume could not be calculated. The investor filled a large graduated cylinder with water, immersed the chunk of gold, and observed an increase in the apparent volume of material in the graduated cylinder of 25.0 mL. Pure gold has a density of 19.3 g/cm3. Did the investor get her money's worth? Why or why not? Ans: No. The investor's metal density is 17.6 g/cm3, thus the bar must not be pure gold. 135. An American engineer who had been transferred to Europe was asked to build bridge pilings exactly as he had in the United States. Each piling required 20.0 cubic yards of concrete in the United States. How many cubic meters of concrete are required for each piling? Given: 1 yd = 0.914 m. Ans: 15.3 m3 136. A soft drink costs 75 cents for a 12-oz can. A two-liter bottle costs $1.25. In which form is the soft drink more expensive? How much more expensive? (1.0 L = 1.057 qt, 1 qt = 32 oz) Ans: The two-liter bottle is the better value. The can is over three times more expensive by volume. 137. A person weighs 150 lb, and the correct dosage of a drug is given as 1.50 mg per kilogram of body weight. How many milligrams of the drug should be given? (2.20 lb = 1 kg) Ans: 102 mg 138. You just measured a block of wood and obtained the following information: mass = 55.120 g length = 8.5 cm height = 4.3 cm width = 3.3 cm Determine the volume and density of the wood block. Ans: Volume of the wood block = 120 cm3; density of the wood block = 0.46 g/cm3. 139. You just measured a metal cylinder and obtained the following information: mass = 3.543 g diameter = 0.53 cm height = 4.4 cm Determine the volume (V) and density of the cylinder. (V=?r2 h, where r = radius, h = height, ? = 3.14) Ans: Volume of the cylinder = 0.97 cm3; density of the cylinder = 3.7 g/cm3. 140. You just measured a sugar cube and obtained the following information: mass = 3.48 g height = length = width = 1.3 cm Determine the volume and density of the cube. Suppose the sugar cube was added to a cup of water. Before it dissolves, will the sugar cube float or sink to the bottom? Ans: Volume of the sugar cube = 2.2 cm3; density of the sugar cube = 1.6 g/cm3. Before dissolving, the sugar cube will sink in a cup of water. 141. An archeologist finds a huge monolith in the desert. In order to estimate the weight of this object; he estimates the dimensions of the monolith and removes some chips from the rock with his hammer, collecting the following data: dimensions of the monolith = 1.5 m ? 5.2 m ? 13 m mass of rock chips = 41.73 g volume of rock chips = 15.2 cm3 Determine the mass of the monolith in pounds, assuming it is of uniform composition. (1 lb = 453.6 g) Ans: 6.1 ? 105 lb 142. What is the density of a salt solution if 50.0 mL of the solution has a mass of 57.0 g? Ans: 1.14 g/mL 143. An excavator is preparing to dig a basement for a new house. Part of his contract reads that he must dispose of all the dirt he removes while digging the basement in an EPA approved landfill. He will dig a hole that is 40 feet wide by 50 feet long and 7.5 feet deep. He first uses his shovel and scoops up 1.00 kg of dirt, and then determines that the dirt has a volume of 600 cm3. The excavator knows that his dump truck can only carry 8,000 kg of dirt. How many dump-truck loads will it take to haul the dirt away? Ans: 89 dump-truck loads 144. How many significant figures does the number 30.340 contain? Ans: 5 145. How many significant figures does the number 0.00721 contain? Ans: 3 146. The number 9.64870 ? 105 contains how many significant figures? Ans: 6 147. What will be the cost of gasoline for a 3,700-mile trip in a car that gets 23 miles per gallon, if the average price of gas is $2.90 per gallon? Ans: $470 148. What will be the cost of gasoline for a 4,700-mile automobile trip if the car gets 41 miles per gallon, and the average price of gas is $2.79 per gallon? Ans: $320 149. The volume of a sphere is given by V = (4/3)?r3 where r is the radius. What is the mass of a magnesium sphere with a radius of 0.80 cm? (The density of magnesium is 1.74 g/cm3.) Ans: 3.7 g 150. The density of lead is 11.4 g/cm3. Express this density in pounds per cubic foot. Ans: 711 lbs/ft3 151. What is the mass of 1.00 dm3 of mercury? The density of mercury is 13.6 g/cm3. Ans: 1.36 ? 104 g 152. The weight of a body varies according to the force of gravity exerted on the body. Ans:  True 153. The mass of a body varies according to the force of gravity exerted on the body. Ans:  False 154. The SI base unit of length is the centimeter. Ans:  False 155. Mass, length, and volume are extensive properties, but density is an intensive property. Ans:  True 156. 20oC is colder than 40?F. Ans:  False 157. 16 megagrams (Mg) is equal to 1.6 ? 107 g. Ans:  True 158. The conversion of water into steam is an example of a chemical change. Ans:  False