Digital Test Bank - Chemistry for Today General,Organic,and Biochemistry,Seager,9e

Chapter 02 - Atoms and Molecules
1. Why is CaO the symbol for calcium oxide instead of CAO?
a. both can be the symbols for calcium oxide
b. both are incorrect; the symbol is cao
c. a capital letter means a new symbol
d. both are incorrect as the symbol should be CaOx
ANSWER: c
POINTS: 1

2. What is the meaning of the two (2) in ethyl alcohol, C2H5OH?
a. all alcohol molecules contain two carbon atoms
b. there are two carbon atoms per molecule of ethyl alcohol
c. carbon is diatomic
d. all of these are correct statements
ANSWER: b
POINTS: 1

3. The symbols for elements with accepted names
a. consist of a single capital letter.
b. consist of a capital letter and a small letter.
c. consist of either a single capital letter or a capital letter and a small letter.
d. No answer is correct.
ANSWER: c
POINTS: 1

4. A molecular formula
a. is represented using the symbols of the elements in the formula.
b. is represented using a system of circles that contain different symbols.
c. cannot be represented conveniently using symbols for the elements.
d. is represented using words rather than symbols.
ANSWER: a
POINTS: 1

5. Which of the following uses the unit of "u" or “amu”?
a. atomic weights of atoms b. relative masses of atoms
c. molecular weights of molecules d. more than one response is correct
ANSWER: d
POINTS: 1

6. What is meant when the symbol C-12 (or 12C) is used?
a. the carbon atom weighs 12 b. the carbon atom weighs 12 pounds
grams
c. the carbon atom weighs 12 amu d. the melting point of carbon is 12°C
ANSWER: c
POINTS: 1

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,Chapter 02 - Atoms and Molecules
7. Refer to a periodic table and tell how many helium atoms (He) would be needed to get close to the
same mass as an average oxygen atom (O).
a. six b. fou c. twelv d. one-fourth
r e
ANSWER: b
POINTS: 1

8. Determine the molecular weight of hydrogen peroxide, H2O2, in u (or amu).
a. 17.01 b. 18.0 c. 34.02 d. 33.01
2
ANSWER: c
POINTS: 1

9. Using whole numbers, determine the molecular weight of calcium hydroxide, Ca(OH)2.
a. 5 b. 57 c. 58 d. 74
6
ANSWER: d
POINTS: 1

10. The average relative mass of an ozone molecule is 48.0 u. An ozone molecule contains only oxygen
atoms. What does this molecular weight indicate about the formula of the ozone molecule?
a. It is b. It is diatomic.
monoatomic.
c. It is triatomic. d. Impossible to determine
ANSWER: c
POINTS: 1

11. Which of the following pairs are about equal in mass?
a. proton and electron b. electron and neutron
c. proton and neutron d. nucleus and surrounding electrons
ANSWER: c
POINTS: 1

12. Which of the following particles is the smallest?
a. proton b. electron
c. neutro d. they are all the same size
n
ANSWER: b
POINTS: 1

13. How many electrons are in a neutral atom of carbon-13 (13C)?
a. 6 b. 18 c. 12 d. no way to tell
ANSWER: a
POINTS: 1

14. Which of the following carries a negative charge?

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,Chapter 02 - Atoms and Molecules

a. a proton b. a neutron
c. an d. both proton and neutron
electron
ANSWER: c
POINTS: 1

15. Which of the following is located in the nucleus of an atom?
a. protons b. neutrons
c. electrons d. protons and neutrons
ANSWER: d
POINTS: 1

16. Atoms are neutral. How can they have no charge?
a. equal numbers of protons and neutrons
b. equal numbers of protons and electrons
c. equal numbers of neutrons and electrons
d. any charge has been drained out of the atom
ANSWER: b
POINTS: 1

17. Isotopes differ from each other in what way?
a. They have different numbers of protons in the nucleus.
b. They have different numbers of neutrons in the nucleus.
c. They have different numbers of electrons outside the nucleus.
d. More than one response is correct.
ANSWER: b
POINTS: 1

18. What is the reason that U-238 is different from U-235?
a. three more electrons b. three more protons
c. three more neutrons d. there is no difference
ANSWER: c
POINTS: 1

19. How many protons are found in the nucleus of a boron-11 (11B) atom?
a. 1 b. 6 c. 5 d. 4
1
ANSWER: c
POINTS: 1

20. How many neutrons are found in the nucleus of a boron-11 (11B) atom?
a. 1 b. 6 c. 5 d. 4
1
ANSWER: b
POINTS: 1

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, Chapter 02 - Atoms and Molecules

21. What is the mass number of a carbon-13 (13C) atom?
a. 13 b. 12 c. 6 d. 7
ANSWER: a
POINTS: 1

22. Naturally occurring neon (Ne) has the following isotopic composition (the mass of each isotope is
given in parenthesis). Calculate the atomic weight of neon in u from these data: neon-20, 90.92%
(19.99 u); neon-21, 0.257% (20.99 u); neon-22, 8.82% (21.99 u)
a. 28.97 b. 37.62 c. 2017 d. 20.17
ANSWER: d
POINTS: 1

23. Naturally occurring lithium (Li) consists of only two isotopes, Li-6 (6.02 u) and Li-7 (7.02 u), where
the isotopic masses are given in parentheses. Use the periodic table and determine which isotope is
present in the larger percentage in the natural element.
a. Li-6
b. Li-7
c. each is present at 50%
d. cannot be determined from the information available
ANSWER: b
POINTS: 1

24. What mass of arsenic (As) in grams contains the same number of atoms as 39.95 g of argon (Ar)?
a. 33.0 b. 74.9 c. 4.1 d. 149.84
2 6
ANSWER: b
POINTS: 1

25. The number of Cr atoms in a 26.0 g sample of chromium is x. How many atoms, expressed in terms
of x, would be contained in 26.98 g of aluminum (Al)?
a. x b. x/2 c. 2x d. x+2
ANSWER: c
POINTS: 1

26. The mass of mercury (Hg), a liquid at room temperature, is 200.6 amu/mol. A 200.6 gram sample of
mercury is heated until it boils. What is the mass of one mole of mercury vapor (gas)?
a. <200.6 or it wouldn’t be a gas b. the same as Avogadro's number
c. the same as when it is a liquid d. none of the answers are correct
ANSWER: c
POINTS: 1

27. The formula for dinitrogen monoxide is N2O. If a sample of the oxide was found to contain 0.0800 g
of oxygen, how many grams of nitrogen would it contain?
a. 0.140 b. 0.280 c. 0.560 d. 0.0700
ANSWER: a
POINTS: 1

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