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1 | |
Which of the following is the correct description of the structure of an atom?
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| | A) | protons in orbit around a central nucleus, which contains electrons and neutrons |
| | B) | neutrons in orbit around a central nucleus, which contains protons and electrons |
| | C) | electrons in orbit around a central nucleus that contains protons and neutrons |
| | D) | electrons and protons in orbits around a central nucleus, which contains neutrons |
| | E) | electrons and neutrons in orbits around a central nucleus, which contains electrons |
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2 | |
What is the atomic number of an atom?
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| | A) | the number of neutrons in the atomic nucleus |
| | B) | the sum of the number of neutrons and protons in the atomic nucleus |
| | C) | the sum of the number of electrons and protons in an atom |
| | D) | the difference between the number of electrons and the number of protons in an atom |
| | E) | the number of protons in the atomic nucleus |
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3 | |
In the chemical formula 2C4H10, how many atoms of each element are represented?
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| | A) | 8 atoms of carbon and 20 atoms of hydrogen |
| | B) | 4 atoms of carbon and 10 atoms of hydrogen |
| | C) | 6 atoms of carbon and 12 atoms of hydrogen |
| | D) | 24 atoms of carbon and 210 atoms of hydrogen |
| | E) | 2 atoms of carbon and 1 atom of hydrogen |
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4 | |
How does an ionic bond differ from a covalent bond?
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| | A) | An ionic bond occurs only between atoms while a covalent bond occurs only between molecules. |
| | B) | An ionic bond is stronger than a covalent bond. |
| | C) | In an ionic bond, one or more electrons transfer from one atom to another; in a covalent bond, one or more electrons are shared by two atoms. |
| | D) | In an ionic bond, one or more electrons are shared by two atoms; in a covalent bond, one or more electrons transfer from one atom to another. |
| | E) | In an ionic bond, protons either transfer or are shared by two atoms, while in a covalent bond, electrons either transfer or are shared by two atoms. |
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5 | |
Which of the following molecular formulas represents a hydrocarbon?
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| | A) | NaCl |
| | B) | H2O |
| | C) | NH3 |
| | D) | C3H8 |
| | E) | CO2 |
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6 | |
Which phase of matter is characterized by a definite volume but not by a definite shape?
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| | A) | gas |
| | B) | liquid |
| | C) | solid |
| | D) | temperature |
| | E) | pressure |
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7 | |
Which of the following is always characteristic of a chemical change but not of a physical change?
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| | A) | change in shape |
| | B) | change in temperature |
| | C) | change in volume |
| | D) | change of phase |
| | E) | the production of a new substance |
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8 | |
How is the reaction N2 + 3H2 → 2NH3 best expressed in words?
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| | A) | 1 molecule of nitrogen gas (N2) combines with 3 molecules of hydrogen gas (H2) to form 2 molecules of ammonia (NH3). |
| | B) | 4 molecules of nitrogen gas (N2) and hydrogen gas (H2) combine to form 2 molecules of ammonia (NH3). |
| | C) | 2 molecules of nitrogen gas (N2) combine with 2 molecules of hydrogen gas (H2) to form 3 molecules of ammonia (NH3). |
| | D) | 1 atom of nitrogen gas (N2) combines with 3 atoms of hydrogen gas (H2) to form 3 molecules of ammonia (NH3). |
| | E) | 1 atom of nitrogen gas (N) combines with 3 atoms of hydrogen gas (H2) to form 2 atoms of ammonia (NH3). |
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9 | |
In which of the following reactions is an activation energy needed to enable the reaction to proceed?
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| | A) | freezing water |
| | B) | dissolving salt in water |
| | C) | paint drying |
| | D) | starting a campfire |
| | E) | a two-part epoxy hardening |
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10 | |
Which of the following is true about the chemical equation
for respiration, shown below?
C6H12O6 + 6 H2O → 6CO2 + 6H2O
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| | A) | There is an equal number of molecules on each side of the reaction arrow. |
| | B) | There are an equal number of atoms on each side of the reaction arrow. |
| | C) | Each molecule is the same phase of matter. |
| | D) | New atoms are created as a result of the reaction. |
| | E) | The total number of atoms decreases during a chemical reaction. |
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2002 McGraw-Hill Higher Education