CHMA10 Chapter 2 Exam Questions

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Department
Chemistry
Course
CHMA10H3
Professor
Xiao- An Zhang
Semester
Fall

Description
Exam Name___________________________________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A 25 g sample of sugar is found to contain 51.4% oxygen by mass. Another 250 g sample of the 1) _______ same sugar is also 51.4% oxygen by mass. This is consistent with the: A) law of multiple proportions. B) first assumption of Dalton's atomic theory. C) second assumption of Dalton's theory. D) law of conservation of mass. E) law of constant composition. 2) When a chemical reaction is carried out in a sealed container, the substances may change in 2) _______ color, temperature or state, but no change in mass is detected. This is evidence of the: A) law of conservation of mass. B) law of definite proportions. C) law of constant composition. D) existance of electrons. E) existance of protons 3) When decomposed chemically, 73.0 grams of a sample of HCl produce 71.0 g of Cl and22.0 g of 3) _______ H 2 while 34.0 g of a sample of H 2 produce 32.0 g of S and 2.0 g of H2. This is an example of the Law: A) E = mc 2 B) of Conservation of Mass C) of Multiple Proportions D) of Definite Proportions E) none of these 4) Choose the INCORRECT statement from those given below. 4) _______ A) Atoms retain their identity during a chemical reaction. B) All atoms of a given element are identical. C) Atoms combine in small, whole-numbered ratios. D) Different ratios of atoms produce different compounds. E) All matter is composed of atoms. 5) A 0.920-gram sample of magnesium is allowed to burn in 0.321 g of oxygen gas. The sole 5) _______ product is magnesium oxide. After the reaction, no oxygen remains and 0.809 g of magnesium oxide has been formed. What mass of magnesium is left unreacted? A) 0.432 g B) 1.408 g C) 0.488 g D) 0.111 g E) 0.210 g 6) Dalton's atomic theory is based on several assumptions which are listed below. Which of these 6) _______ assumptions is strictly correct? I) All atoms of the same element are identical. II) Atoms are indivisible and unchangeable. III) Chemical changes are the result of the combination, separation, and rearrangement of atoms. A) II and III are correct. B) I and II are correct. C) I and III are correct. D) I, II, and III are correct. E) III is correct. 7) Choose the INCORRECT statement. 7) _______ A) Objects of like charge repel each other. B) Gamma rays are the same as electrons. C) The Law of Constant Composition is the Law of Definite Proportions. D) Electrons were once known as cathode rays. E) Alpha rays are the same mass as a helium nucleus. 8) Which of the following statements is NOT true? 8) _______ A) J.J. Thomson suggested the "plum pudding" model of the atom. B) Robert Millikan determined the charge on an electron. C) Michael Faraday determined that cathode rays were the fundamental negatively charged particles and called them electrons. D) J.J. Thomson determined the charge-to-mass ratio for electrons. E) Michael Faraday discovered cathode rays. 9) Which of the following would NOT be affected by an electric field? 9) _______ A) Alpha particles B) protons C) Gamma rays D) Beta particles E) electrons 10) Choose the correct statement. 10) ______ A) An electron has 1/1837 the mass of a proton B) Electrons and protons have about the same mass C) The charge of a proton is 1837 times the charge of an electron D) The atomic number is the total number of protons and neutrons in the nucleus E) Neutrons have no charge and no mass 11) Which of the following is a correct feature of the nuclear atom proposed by Rutherford? 11) ______ A) All atoms of an element have the same mass. B) The number of neutrons and electrons in the atom are equal. C) It is like the "plum pudding" model. D) The atom is mostly empty space. E) The majority of alpha particles to strike the foil "bounced back." 12) Beta particles: 12) ______ A) are high speed electrons. B) have a mass of 4 and a charge of +2. C) have the same mass as a neutron. D) are like x-rays. E) are repelled by a positively charged plate. 13) Ernest Rutherford is credited with: 13) ______ I) the nuclear model of the atom. II) the identification of alpha and beta particles. III) the discovery of protons. IV) the prediction of a third, neutral, subatomic particle. A) I and II B) I and III C) I, II, III D) II, III, IV E) I, II, III, IV 14) Choose the INCORRECT statement. 14) ______ A) The atomic number is the proton number. B) The mass number is the number of protons plus neutrons. C) Protons and neutrons are found in the nucleus. D) Gamma rays are bent by magnetic fields as a ray of positive charges. E) Protons and neutrons are close to the same mass. 15) What is the mass number of the most abundant form of oxygen atom? 15) ______ A) 15.9994 B) 32 C) 24 D) 16 E) 8 16) Which of these atoms has the greatest number of neutrons in its nucleus? 16) ______ A) B) C) D) E) Co Si Ni Fe Mn 17) Choose the information that could NOT be found with a mass spectrometer. 17) ______ A) the mass of a proton B) the relative abundance of two isotopes of potassium C) the number of stable isotopes of potassium D) the number of protons in potassium E) the atomic mass of a single isotope of potassium 18) A species which differs in charge from another atom of the same element: 18) ______ I) is called an isotope II) has more or less neutrons III) has lost or gained electrons IV) is called an ion V) has the same number of protons A) I and II B) I and III C) II and IV D) III and IV E) III, IV, V 19) Which of the following statements is true concerning the masses of individual Cl atoms? 19) ______ A) None of the atoms have a mass of 35.45 u. B) Most of the atoms have a mass of 35.45 u. C) All atoms have a mass of 35.45 u. D) All atoms have a mass of 17 u. E) Some of the atoms have a mass of 35.45 u. 20) A hypothetical element Z has two stable isotopes: 20) ______ Z-46 = 46.046 u 64.08% Z-51 = 50.826 u 35.92% What is the average atom weight of the element? A) 47.76 u B) 47.44 u C) 49.11 u D) 48.50 u E) 48.44 u 21) A hypothetical element, Z, has two stable isotopes. 21) ______ Z-38 = 38.012 u 75.68% Z-46 = 45.981 u 24.32% The element's atomic mass would be closest to which of the elements? A) Ar B) Ca C) Sc D) K E) none of these 22) The atomic weight of chlorine is very close to 35.5. This means that: 22) ______ A) chlorine occurs with a variable number of protons B) on the average, an atom of chlorine weighs almost 3 times as much as carbon C) a variable number of electrons gives the fractional weight D) the actual weight of a chlorine atom is not known very precisely E) chlorine atoms contain half of a proton 23) An element has 5 stable isotopes. The mass and percentage of each are: 23) ______ 69.9243 20.52% 71.9217 27.43% 72.9234 7.76% 73.9219 36.54% 75.9214 7.76% The element is which of the following? A) Zn B) Ge C) Se D) Ga E) As 24) An element has 5 stable isotopes. The mass and percentage of each are: 24) ______ 89.9043 51.46% 90.9053 11.23% 91.9046 17.11% 93.9061 17.40% 95.9082 2.80% The element is which of the following? A) Y B) Nb C) Sr D) Rb E) Zr 25) Which statement below is true? 25) ______ A) Metals lose electrons to have a positive charge. B) Transition metals can gain 2 or more electrons to become metal ions. C) Metals gain electrons to have a negative charge. D) Metals gain electrons to have a positive charge. E) Nonmetals lose electrons. 26) Groups, or families, on the periodic table are: 26) ______ A) extremely reactive with each other. B) elements which all occur naturally in the same state. C) vertical columns of elements with similar properties. D) named for the first elements in the series; such as "actinides." E) horizontal rows of elements with increasing atomic numbers. 27) Which of the following is NOT a metal? 27) ______ A) bismuth B) radium C) calcium D) selenium E) mercury 28) If we consider 1 atomic mass unit to be equal to grams, calculate the average 28) ______ mass in grams of one Argon atom, atomic number 18. A) 2.989 × 10-23g B) 2.406 × 10-23g C) 2.406 × 10-25g D) 1.084 × 10-25g E) 6.634 × 10-23g 29) What is the mass in grams of 1 atom of sulfur 29) ______ A) -23 5.325 × 10 B) 1.931 × 10-25 C) 5.179 × 10-26 D) 5.989 × 10-23 E) -24 1.661 × 10 30) 31.0 grams of the element phosphorus: 30) ______ A) contain 31.0 × (6.02 × 103) P atoms B) contain 6.02 × 1023P atoms C) contain 31.0 P atoms D) contain 31.0 moles of P E) contain 6.02 × 1023P 4olecules 31) How many atoms are in 5.21 g of arsenic? 31) ______ A) 0.0695 B) 4.19 × 1022 C) 2.10 × 1022 D) 22 9.51 × 10 E) 3.14 × 104 32) A cubic centimeter of lead weighs 11.35 g. How many atoms are in the block? 32) ______ A) 25 1.1 × 10 B) 2.4 × 10 C) 5.3 × 102 D) 6.8 × 104 E) 22 3.3 × 10 33) How many moles are represented by Na atoms? 33) ______ A) 4.2 × 109 B) 3.8 × 1010 C) 14 1.1 × 10 D) 1.8 × 1010 E) 1.5 × 109 34) The natural abundance of calcium in the earth's crust is 3.4% by mass. How many calcium atoms 34) ______ are present in a 1.50 g sample of the earth's crust? A) 7.7 × 100 B) 6.6 × 103 C) 5.1 × 100 D) 3.1 × 102 E) 22 7.7 × 10 35) 57.7 g Ni contains how many atoms? 35) ______ A) 1.24 × 104 B) 23 6.13 × 10 C) 0.983 D) 3.47 × 103 E) 23 5.92 × 10 36) 36) ______ How many atoms of silicon are contained in grams? A) 5.02 × 108 atoms B) 1.82 × 108 atoms C) 20 1.82 × 10 atoms D) 1.44 × 103 atoms E) 5.02 × 100 atoms 37) If the density of lead is 11.34 g/cm , how many atoms are in a piece of lead that is 2.00cm wide,7) ______ 1.00m long, and 2.00 mm thick? A) 1.32 × 103 B) 6.60 × 103 C) 1.16 × 103 D) 1.32 × 104 E) 1.16 × 102 38) How many atoms of rubidium-85 are in 87.2 g of rubidium. Rubidium-85 is 72.2 % abundant. 38) ______ A) 4.44 × 103 B) 6.14 × 10 C) 1.02 × 104 D) 5.16 × 106 E) 23 8.51 × 10 39) How many atoms of hydrogen are present in 1.5 lb of hydrogen peroxide, which is 5.93% 39) ______ hydrogen? A) 25 2.4 × 10 atoms B) 1.21 × 105 atoms C) 2.41 × 105 atoms D) 1.2 × 100 atoms E) 25 1.2 × 10 atoms 40) How many atoms of sulfur are in 280 g of a 50% H2SO 4olution? 40) ______ A) 8.0 × 105 atoms B) 29 2.8 × 10 atoms C) 8.6 × 103 atoms D) 8.0 × 103 atoms E) 8.6 × 105 atoms 41) How many Cu atoms are present in a 75.0 cm length of 20-gauge copper wire? A 20-gauge wire 41) ______ has a diameter of 0.03196 in. Copper's density is 8.92 g/cm . A) 3.28 × 102 B) 21 1.31 × 10 C) 8.08 × 101 D) 1.04 × 102 E) 22 2.08 × 10 42) How many atoms of lead are required to cover a 33.0 cm
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