Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
1.Atoms consist principally of what three fundamental particles?
a. electrons, positrons, and neutrons b. elements, positrons, and neutrons c. elements, protons, and neutrons d. electrons, protons, and molecules e. electrons, protons, and neutrons 2.Which of the following statements is incorrect?
a. A molecule is the smallest particle of a compound that can have a stable independent existence.
b. Molecules that consist of more than one atom are called polyatomic molecules.
c. The atomic number of an element is defined as the number of neutrons in the nucleus.
d. Molecules of compounds are composed of more than one kind of atom.
e. The charge on an electron is negative, and the charge on a proton is positive.
3.If a sample of propane, C3H8, contains a total of 6.0 × 103 atoms of carbon, how many molecules of propane are in the sample?
a. 6.0 × 103 b. 3.0 × 103 c. 8.0 × 103 d. 1.1 × 104 e. 2.0 × 103
4.What is the formula for manganese(III) oxide?
a. MgO b. MnO c. MnO4
d. Mg2O3
e. Mn2O3
5.Choose the name-formula pair that does not correctly match.
a. aluminum phosphate AlPO4
b. calcium acetate CaCH3COO c. ammonium sulfide (NH4)2S d. magnesium hydroxide Mg(OH)2
e. zinc carbonate ZnCO3
6.From the following ionic compounds, choose the name-formula pair that is not correctly matched.
a. sodium sulfide Na2S b. ammonium nitrate NH4NO3
c. zinc hydroxide Zn(OH)2
d. sodium sulfate Na2SO3
e. calcium oxide CaO
7.Calculate the number of moles of oxygen atoms in 35.2 grams of oxygen.
a. 2.20 moles b. 4.42 moles c. 0.54 moles d. 2.57 moles e. 1.13 moles
8.Determine the formula weight of potassium phosphate.
a. 134 amu b. 257 amu c. 164 amu d. 212 amu e. 85 amu
9.What is the mass of 2.2 × 109 CO2 molecules?
a. 9.7 × 1010 g b. 1.0 × 10-12 g c. 1.2 × 106 g d. 4.4 × 10-14 g e. 1.6 × 10-13 g
10.How many grams of calcium chloride equal 3.40 moles of calcium chloride2? a. 130 g
b. 159 g c. 306 g d. 377 g e. 239 g
11.Which of the following is not a correct description of 16.0 grams of methane, CH4? a. It is one mole of methane.
b. It is the amount of methane that contains 12.0 g of carbon.
c. It is 16.0 × 6.02 × 1023 molecules of methane.
d. It is the amount of methane that contains 4.0 grams of hydrogen.
e. It is the amount of methane that contains 4 × 6.02 × 1023 hydrogen atoms.
12.Which statement regarding the "gold foil" experiment is false?
a. It was performed by Rutherford and his research group early in the 20th century.
b. Most of the alpha particles passed through the foil undeflected.
c. The alpha particles were repelled by electrons.
d. It suggested the nuclear model of the atom.
e. It suggested that atoms are mostly empty space.
13.The Rutherford "gold foil experiment" suggested __________.
a. that electrons have negative charges
b. that protons have charges equal in magnitude but opposite in sign to those of electrons c. that atoms have a tiny, positively charged, massive center
d. the ratio of the mass of an electron to the charge of the electron e. the existence of canal rays
14.The difference between the mass number of an atom and the atomic number of the atom is always equal to __________.
a. 6.02 × 1023
b. the atomic number of the element c. the atomic mass unit
d. the number of protons in the nucleus e. the number of neutrons in the nucleus
15.Give the number of protons, neutrons, and electrons in an atom of the 90Sr isotope.
a. 38 p, 38 n, 38 e b. 38 p, 90 n, 38 e c. 52 p, 38 n, 52 e d. 38 p, 52 n, 38 e e. 90 p, 38 n, 90 e
16.Give the number of protons, neutrons, and electrons in an atom of the 41K isotope.
a. 19 p, 22 n, 22 e b. 41 p, 19 n, 41 e c. 19 p, 22 n, 19 e d. 19 p, 16 n, 19 e e. 15 p, 26 n, 15 e
17.Give the number of protons, neutrons, and electrons in the ion.
a. 16 p, 18 n, 16 e b. 16 p, 18 n, 14e c. 16 p, 16 n, 19 e d. 16 p, 18 n, 18 e e. 34 p, 16 n, 18 e
18.What is the symbol for an atom composed of 33 protons, 42 neutrons, and 33 electrons?
a.
b.
c.
d.
e.
19.What is the symbol for a species composed of 38 protons, 52 neutrons, and 36 electrons?
a. 90Kr2+
b. 90Sr2+
c. 90Sr d. 52Kr e. 38Th2+
20.How many neutrons does the phosphorus isotope contain?
a. 8 b. 2 c. 15 d. 17 e. 32
21.Which response includes all the following statements that are true, and no false statements?
I. Isotopes of an element differ only in the number of protons.
II. The number of protons in an atom is its atomic number.
III. The mass number of an atom is the sum of the number of protons plus electrons in the atom.
IV. The volume occupied by the nucleus of an atom represents a large percentage of the total volume of the atom.
a. I and III b. II, III, and IV c. II and IV d. II e. I and IV
22.If an element consisted of three isotopes in the following relative abundance, what would the atomic weight of the element be?
This is a hypothetical example.
30.00% 37.00 amu
50.00% 38.00 amu
20.00% 40.00 amu
a. 38.00 amu b. 38.10 amu c. 38.20 amu d. 39.98 amu e. none of these
23.Gallium has two naturally occurring isotopes. 69Ga (68.9257 amu) is the more abundant isotope, at 60.4%. If the atomic mass of gallium is 69.723 amu, what is the mass of the other isotope, 71Ga?
a. 71 amu b. 71.512 amu c. 39.60 amu d. 69.985 amu e. 70.925 amu
24.Which element has a mass approximately 32 times that of a H atom?
a. C b. S c. Mo d. Cu e. Ar
25.Determine the number of sulfur atoms in 27.1 g of molecular sulfur (S8).
a. 0.845 b. 5.27 × 1023 c. 5.09 × 1023 d. 2.07 × 1023 e. 0.106
26.Calculate the formula weight of sodium sulfate..
a. 193 amu b. 119 amu c. 142 amu d. 215 amu e. 185 amu
27.How many moles of POCl3 are there in 10.0 grams of POCl3? a. 6.51 × 10-2 mol
b. 3.68 × 10-1 mol c. 4.09 × 10-2 mol d. 1.21 × 10-1 mol e. 1.17 × 10-3 mol
28.How many molecules are contained in 5.00 grams of NH3? a. 5.42 × 1022
b. 3.00 × 1024 c. 3.40 × 1022 d. 1.77 × 1023 e. 9.45 × 1022
29.How many atoms of carbon are present in 34.5 g of caffeine, C8H10N4O2? a. 8.57 × 1023
b. 2.68 × 1025 c. 1.08 × 1024 d. 2.09 × 1023 e. 4.83 × 1023
30.What mass of iron is contained in 86.6 grams of pyrite, FeS2? a. 40.3 g
b. 29.2 g c. 47.3 g d. 80.6 g e. 64.1 g
Answer Section MULTIPLE CHOICE
1. ANS: E TOP: Atoms and Molecules 2. ANS: C TOP: Atoms and Molecules
3. ANS: E TOP: Chemical Formulas
4. ANS: E TOP: Names and Formulas of Some Ionic Compounds 5. ANS: B TOP: Names and Formulas of Some Ionic Compounds 6. ANS: D TOP: Names and Formulas of Some Ionic Compounds
7. ANS: A TOP: The Mole
8. ANS: D TOP: Formula Weights, Molecular Weights, and Moles 9. ANS: E TOP: Formula Weights, Molecular Weights, and Moles 10. ANS: D TOP: Formula Weights, Molecular Weights, and Moles 11. ANS: C TOP: Formula Weights, Molecular Weights, and Moles 12. ANS: C TOP: Fundamental Particles and the Nuclear Atom 13. ANS: C TOP: Fundamental Particles and the Nuclear Atom 14. ANS: E TOP: Mass Number and Isotopes
15. ANS: D TOP: Mass Number and Isotopes 16. ANS: C TOP: Mass Number and Isotopes 17. ANS: D TOP: Mass Number and Isotopes 18. ANS: E TOP: Mass Number and Isotopes 19. ANS: B TOP: Mass Number and Isotopes 20. ANS: D TOP: Mass Number and Isotopes 21. ANS: D TOP: Mass Number and Isotopes
22. ANS: B TOP: The Atomic Weight Scale and Atomic Weights 23. ANS: E TOP: The Atomic Weight Scale and Atomic Weights
24. ANS: B TOP: Atomic Weights
25. ANS: C TOP: The Mole
26. ANS: C TOP: Formula Weights, Molecular Weights, and Moles 27. ANS: A TOP: Formula Weights, Molecular Weights, and Moles 28. ANS: D TOP: Formula Weights, Molecular Weights, and Moles
29. ANS: A TOP: Formula Weights, Molecular Weights, and Moles 30. ANS: A TOP: Some Other Interpretations of Chemical Formulas
