(Verified Answers)
1. What is a hypothesis?
a. the summary of a large quantity of information
b. an attempt to explain an observation, or a series of observations
c. a fact that results from extensive experimentation and testing
d. the result of a single measurement or observation
e. an observation of a chemical reaction: b
2. Which statement concerning atoms is FALSE?
a. The atomic number of an atom is the number of protons it contains.
b. The mass number of an atom is the sum of the number of protons, neutrons, and
electrons it contains.
c. The nucleus of an atom is the heaviest part of the atom.
d. The nucleus of an atom contains its protons and neutrons, and is positively
charged.
e. Electrons reside outside the nucleus in what is called the electron cloud.: b
3. What is always true for a neutral atom?
a. The number of protons, neutrons, and electrons is an even number.
b. There is an equal number of protons, neutrons, and electrons.
,c. There is an equal number of protons and electrons.
d. There is an equal number of protons and neutrons.
e. The number of protons and neutrons is an even number.: c
4. What is Rutherford's important contribution to our knowledge of atomic
structure?
a. Electrons in an atom have the magnetic property of spin.
b. The atom cannot be created, divided, destroyed, or converted to any other type
of atom.
c. Atoms contain a small, dense, positively charged nucleus, surrounded
largely by empty space.
d. Electrons follow circular paths around the nucleus of an atom.
e. Electrons are confined to certain specific regions of space outside the
nucleus: c
5. What was J. J. Thomson's important discovery about cathode rays in 1897?
a. Cathode rays were produced by all radioactive atoms.
b. Cathode rays consisted of a stream of electrons.
c. Cathode rays were heavier than anode rays.
d. Cathode rays were indestructible.
e. Cathode rays were able to initiate radioactive decay of an atom.: b
6. Which statement about chemical bonds is FALSE?
a. The electrons in covalent bonds may be shared equally or unequally be- tween
the atoms.
,b. The sharing of electrons between two nonmetals results in a covalent bond.
c. A bond dipole is the separation of charge that results when atoms sharing
electrons have different electronegativity values.
d. The attraction between oppositely charged ions results in an ionic bond.
e. A nonpolar covalent bond is one in which electrons are not shared equally
between the atoms.: e
7. A molecule of deoxyribose, an essential part of DNA, contains five carbon
atoms, ten hydrogen atoms, and four oxygen atoms. How would the formula of
deoxyribose be represented?
a. 5C10H4O
b. C5H10O4
c. C5H10O4
d. C5H10O4
e. All formulas are acceptable.: b
8. Considering the electronegativity values indicated in the table, which cova- lent
bond is the most polar?
a. F F
b. H F
c. Cl F
d. N O
e. C H: b
9. What is the mass of one mole of diatomic hydrogen, H2? a.
1.01 g
b. 2.02 g
c. 1.01 amu
, d. 2.02 amu
e. 6.022 × 1023 g: b
10. The chemical equation below is unbalanced. What is the coefficient of water
when the equation is balanced? Mg(OH)2(s) + HCl(g) ’ MgCl2(s) + H2O(l)
a. 3
b. 1
c. 2
d. 4
e. No coefficient would be shown.: c
11. The mass of one atom of oxygen is 16.00 amu. What is the mass of one mole
of elemental oxygen (O2)?
a. 9.64 × 1024 g
b. 1.88 × 1022 g
c. 32.00 amu