1. Which statement describes a chemical property of the element magnesium? A) Magnesium is malleable. B) Magnesium conducts electricity. C) Magnesium reacts with an acid. D) Magnesium has a high boiling point. 2. Which nuclear emission has the greatest penetrating power? A) alpha particle B) beta particle C) gamma radiation D) positron 3. Which notation represents an atom of sodium with an atomic number of 11 and a mass number of 24? A) B) C) D) 4. A neutron has approximately the same mass as A) an alpha particle B) a beta particle C) an electron D) a proton 5. The heating curve below represents a sample of a substance starting as a solid below its melting point and being heated over a period of time. 6. Which particle can not be accelerated by the electric or magnetic fields in a particle accelerator? A) neutron B) proton C) alpha particle D) beta particle Which statement describes the energy of the particles in this sample during interval DE? A) Both potential energy and average kinetic energy increase. B) Both potential energy and average kinetic energy decrease. C) Potential energy increases and average kinetic energy remains the same. D) Potential energy remains the same and average kinetic energy increases.
7. Given the diagram representing a process being used to separate the colored dyes in food coloring: Which process is represented by this diagram? A) chromatography B) electrolysis C) distillation D) titration 8. The graph below represents the uniform heating of a substance, starting with the substance as a solid below its melting point. Which segment of the graph represents a time when both the solid and liquid phases are present? A) AB B) BC C) DE D) EF 9. How much energy is required to vaporize 10.00 grams of water at its boiling point? A) 2.26 kj B) 3.34 kj C) 4.2 kj D) 22.6 kj 10. The elements on the Periodic Table are arranged in order of increasing A) boiling point B) electronegativity C) atomic number D) atomic mass 11. In a laboratory where the air temperature is 22 C, a steel cylinder at 100. C is submerged in a sample of water at 40. C. In this system, heat flows from A) both the air and the water to the cylinder B) both the cylinder and the air to the water C) the air to the water and from the water to the cylinder D) the cylinder to the water and from the water to the air 12. Which is a measure of the average kinetic energy of the particles of a substance? A) pressure B) mass C) density D) temperature 13. At STP, which physical property of aluminum always remains the same from sample to sample? A) mass B) density C) length D) volume 14. Which substance can not be decomposed by a chemical change? A) Ne B) N2O C) HF D) H2O 15. When 200 grams of water cools from 50. C to 25 C, the total amount of heat energy released by the water is A) 42 kj B) 21 kj C) 34 J D) 17 J
16. Which kelvin temperature is equal to 56 C? A) -329 K B) -217 K C) 217 K D) 329 K 17. Which quantities must be conserved in all chemical reactions? A) mass, charge, density B) mass, charge, energy C) charge, volume, density D) charge, volume, energy 18. Which particle has the least mass? A) alpha particle B) beta particle C) neutron D) proton 19. Two substances, A and Z, are to be identified. Substance A can not be broken down by a chemical change. Substance Z can be broken down by a chemical change. What can be concluded about these substances? A) Both substances are elements. B) Both substances are compounds. C) Substance A is an element and substance Z is a compound. D) Substance A is a compound and substance Z is an element. 20. An electron has a charge of A) 1 and the same mass as a proton B) +1 and the same mass as a proton C) 1 and a smaller mass than a proton D) +1 and a smaller mass than a proton 21. What is the product of (2.324 cm 1.11 cm) expressed to the correct number of significant figures? A) 2.58 cm 2 B) 2.5780 cm 2 C) 2.5796 cm 2 D) 2.57964 cm 2 22. Recovering the salt from a mixture of salt and water could best be accomplished by A) evaporation B) filtration C) paper chromatography D) density determination 23. Which type of matter is composed of two or more different elements that are chemically combined in a definite ratio? A) a solution B) a compound C) a homogeneous mixture D) a heterogeneous mixture 24. An oxide ion (O 2 ) formed from an oxygen-18 atom contains exactly A) 8 protons, 8 neutrons, 10 electrons B) 8 protons, 10 neutrons, 8 electrons C) 8 protons, 10 neutrons, 10 electrons D) 10 protons, 8 neutrons, 8 electrons 25. Which principal energy level can hold a maximum of 18 electrons? A) 5 B) 2 C) 3 D) 4 26. What is the maximum number of electrons in an orbital of any atom? A) 1 B) 2 C) 6 D) 10 27. What is the total amount of heat required to completely melt 347 grams of ice at its melting point? A) 334 J B) 1,450 J C) 116,000 J D) 784,000 J 28. An atom of helium-4 differs from an atom of lithium-7 in that the atom of helium-4 has A) one more proton B) one more neutron C) two less protons D) two less neutrons 29. Which measurement contains three significant figures? A) 0.05 g B) 0.050 g C) 0.056 g D) 0.0563 g 30. Which electron configuration represents an atom in an excited state? A) 2-6 B) 2-7 C) 2-7-1 D) 2-8-1 31. Which equation represents a physical change? A) H2O(s) + 6.01 kj H2O( ) B) 2H2(g) + O2(g) 2H2O(g) + 483.6 kj C) H2(g) + I2(g) + 53.0 kj 2HI(g) D) N2(g) + 2O2(g) + 66.4 kj 2NO2(g)
32. Which is the electron configuration of a neutral atom in the ground state with a total of six valence electrons? A) 2-4 B) 2-6 C) 2-8 D) 2-8-8 33. Which subatomic particles have a mass of approximately 1 atomic mass unit each? A) proton and electron B) proton and neutron C) neutron and positron D) electron and positron 34. Which notations represent hydrogen isotopes? A) B) C) D) 35. A substance that is composed only of atoms having the same atomic number is classified as A) a compound B) an element C) a homogeneous mixture D) a heterogeneous mixture 36. Which of these phrases best describes an atom? A) a positive nucleus surrounded by a hard negative shell B) a positive nucleus surrounded by a cloud of negative charges C) a hard sphere with positive particles uniformly embedded D) a hard sphere with negative particles uniformly embedded 37. The diagram below represents a portion of a 100-milliliter graduated cylinder. What is the reading of the meniscus? A) 35.0 ml B) 36.0 ml C) 44.0 ml D) 45.0 ml 38. Solid A at 80ºC is immersed in liquid B at 60ºC. Which statement correctly describes the energy changes between A and B? A) A releases heat and B absorbs heat. B) A absorbs heat and B releases heat. C) Both A and B absorb heat. D) Both A and B release heat. 39. What is the number of electrons in an atom that has 3 protons and 4 neutrons? A) 1 B) 7 C) 3 D) 4 40. Which substance can be decomposed by a chemical change? A) Co B) CO C) Cr D) Cu 41. Which group of atomic models is listed in historical order from the earliest to the most recent? A) hard-sphere model, wave-mechanical model, electron-shell model B) hard-sphere model, electron-shell model, wave-mechanical model C) electron-shell model, wave-mechanical model, hard-sphere model D) electron-shell model, hard-sphere model, wave-mechanical model
42. Given the nuclear equation: 48. The diagram below shows the upper part of a laboratory burner. What is particle X? A) an alpha particle B) a beta particle C) a deuteron D) a triton 43. Which two particles each have a mass approximately equal to one atomic mass unit? A) electron and neutron B) electron and positron C) proton and electron D) proton and neutron 44. Which change of phase is exothermic? A) NaCl(s) NaCl( ) B) CO2(s) CO2(g) C) H2O( ) H2O(s) D) H2O(s) H2O(g) 45. Which quantity is equivalent to 50 kilojoules? A) 5000 J B) 0.05 J C) 5 10 3 J D) 5 10 4 J 46. What is the nuclear charge of an atom with a mass of 23 and an atomic number of 11? A) 11+ B) 12+ C) 23+ D) 34+ 47. Which substance can be decomposed by a chemical change? A) sodium B) argon C) sulfur D) ammonia Which letter represents the hottest part of the burner flame? A) A B) B C) C D) D 49. What is the total number of electrons in the second energy shell of a calcium atom in the ground state? A) 6 B) 2 C) 8 D) 18 50. When a fluorine atom becomes an ion, it will A) gain an electron and decrease in size B) gain an electron and increase in size C) lose an electron and decrease in size D) lose an electron and increase in size 51. The atomic number of an atom is always equal to the total number of A) neutrons in the nucleus B) protons in the nucleus C) neutrons plus protons in the atom D) protons plus electrons in the atom 52. Which change of phase represents sublimation? A) solid to liquid B) solid to gas C) liquid to gas D) liquid to solid 53. Sodium atoms differ from sodium ions in that sodium atoms contain A) one more proton B) one less proton C) one more electron D) one less electron
54. Nonmetallic elements in the solid phase tend to be A) malleable B) ductile C) brittle D) conductors 55. Which grouping of the three phases of bromine is listed in order from left to right for increasing distance between bromine molecules? A) gas, liquid, solid B) liquid, solid, gas C) solid, gas, liquid D) solid, liquid, gas 56. A dry mixture of KNO3 and sand could be separated by A) adding water to the mixture and filtering B) adding water to the mixture and evaporating C) heating the mixture to a high temperature D) cooling the mixture to a low temperature 57. Element X has two isotopes. If 72.0% of the element has an isotopic mass of 84.9 atomic mass units, and 28.0% of the element has an isotopic mass of 87.0 atomic mass units, the average atomic mass of element X is numerically equal to A) B) C) D) 58. Which statement describes a chemical property of iron? A) Iron can be flattened into sheets. B) Iron conducts electricity and heat. C) Iron combines with oxygen to form rust. D) Iron can be drawn into a wire. 59. The atomic mass of magnesium is the weighted average of the atomic masses of A) all of the artificially produced isotopes of Mg B) all of the naturally occurring isotopes of Mg C) the two most abundant artificially produced isotopes of Mg D) the two most abundant naturally occurring isotopes of Mg 60. What is the mass number of an atom which contains 21 electrons, 21 protons, and 24 neutrons? A) 21 B) 42 C) 45 D) 66 61. A student investigated the physical and chemical properties of a sample of an unknown gas and then identified the gas. Which statement represents a conclusion rather than an experimental observation? A) The gas is colorless. B) The gas is carbon dioxide. C) When the gas is bubbled into limewater, the liquid becomes cloudy. D) When placed in the gas, a flaming splint stops burning. 62. What fraction of a Sr-90 sample remains unchanged after 87.3 years? A) 1 2 B) 1 3 C) 1 4 D) 1 8 63. Which subatomic particles are located in the nucleus of an He-4 atom? A) electrons and neutrons B) electrons and protons C) neutrons and protons D) neutrons, protons, and electrons 64. A student found the boiling point of a liquid to be. If the liquid's actual boiling point is, the experimental percent error is equal to A) B) C) D) 65. An example of a physical property of an element is the element s ability to A) react with an acid B) react with oxygen C) form a compound with chlorine D) form an aqueous solution
66. The graph below represents the uniform heating of a substance, starting below its melting point, when the substance is solid. Which line segments represent an increase in average kinetic energy? A) and B) and C) and D) and 67. Which formula represents a mixture? A) NaCl(aq) B) NaCl(s) C) H2O( ) D) H2O(s) 68. Base your answer to the following question on the diagram below, which shows bright-line spectra of selected elements. Identify the two elements in the unknown spectrum.
Base your answers to questions 69 through 71 on the information below and on your knowledge of chemistry. A student compares some models of the atom. These models are listed in the table below in order of development from top to bottom. 69. State the model that first included electrons as subatomic particles. 70. Using the conclusion from the Rutherford model, identify the charged subatomic particle that is located in the nucleus. 71. State one conclusion about the internal structure of the atom that resulted from the gold foil experiment. 72. Base your answer to the following question on the information below. A glass tube is filled with hydrogen gas at low pressure. An electric current is passed through the gas, causing it to emit light. This light is passed through a prism to separate the light into the bright, colored lines of hydrogen's visible spectrum. Each colored line corresponds to a particular wavelength of light. One of hydrogen's spectral lines is red light with a wavelength of 656 nanometers. Tubes filled with other gases produce different bright-line spectra that are characteristic of each kind of gas. These spectra have been observed and recorded. Explain, in terms of electron energy states and energy changes, how hydrogen's bright-line spectrum is produced. 73. A plan is being developed for an experiment to test the effect of concentrated strong acids on a metal surface protected by various coatings. Some safety precautions would be the wearing of chemical safety goggles, an apron, and gloves. State one additional safety precaution that should be included in the plan. 74. Draw a Lewis electron-dot diagram of a selenium atom in the ground state.
75. Base your answer to the following question on the information below. An unlit candle is secured to the bottom of a 200-milliliter glass beaker. Baking soda (sodium hydrogen carbonate) is added around the base of the candle as shown below. The candle is lit and dilute ethanoic acid is poured down the inside of the beaker. As the acid reacts with the baking soda, bubbles of CO2 gas form. After a few seconds, the air in the beaker is replaced by 0.20 liter of CO2 gas, causing the candle flame to go out. The density of CO2 gas is 1.8 grams per liter at room temperature. Calculate the mass of the CO2 gas that replaced the air in the beaker. Your response must include both a correct numerical setup and the calculated result.
Answer Key Benchmark 2 Practice 1. C 2. C 3. A 4. D 5. C 6. A 7. A 8. B 9. D 10. C 11. D 12. D 13. B 14. A 15. B 16. D 17. B 18. B 19. C 20. C 21. A 22. A 23. B 24. C 25. C 26. B 27. C 28. D 29. D 30. C 31. A 32. B 33. B 34. A 35. B 36. B 37. A 38. A 39. C 40. B 41. B 42. A 43. D 44. C 45. D 46. A 47. D 48. C 49. C 50. B 51. B 52. B 53. C 54. C 55. D 56. A 57. C 58. C 59. B 60. C 61. B 62. D 63. C 64. A 65. D 66. B 67. A 68. H and He or hydrogen and helium. 69. Thomson model Thomson plum pudding model 70. proton p p + 11p 1 1 H H + 71. An atom is mainly empty space. It has a nucleus. The small, dense nucleus is positively charged. 72. Examples: The electron of hydrogen absorbs energy and jumps to a higher energy state. The excited electron returns to a lower energy state, releasing light energy The e absorbs energy and jumps to a higher level. The e falls back to a lower level and releases energy related to a particular color. 73. Acceptable responses: Perform tests under ventilation (fume) hood; Avoid spills; no open-toed shoes. 74. 75. Examples: m = Vd = (0.20 L)(1.8 g/l); (0.2)(1.8); 0.36 g