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| 1 | |
Which of the following subatomic particles is found in an orbital? |
| | A) | Electron |
| | B) | Hydrogen |
| | C) | Proton |
| | D) | Neutron |
| | E) | All of the choices are subatomic particles. |
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| 2 | |
Which of the following molecular formulas does not represent a compound? |
| | A) | H2O |
| | B) | CO2 |
| | C) | N2 |
| | D) | C6 H12O6 |
| | E) | NaCl |
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| 3 | |
Which one of the following statements about water is incorrect? |
| | A) | Ice floats on water because the H2O molecules in ice are spaced farther apart and are therefore less dense than the H2 molecules in water. |
| | B) | Water has a high heat of fusion, but a low heat of vaporization. |
| | C) | Water can be found as a solid, liquid, or gas, but is most commonly found on Earth as a liquid. |
| | D) | Addition of solutes to water raises its boiling point and lowers its freezing point. |
| | E) | Water can act as a direct participant in some biological reactions. |
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| 4 | |
True or False: An atomic nucleus has a net neutral charge because of the balance of protons and neutrons. |
| | A) | True |
| | B) | False |
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| 5 | |
What conclusion did Ernest Rutherford draw from his gold foil experiment described in the Feature Investigation? |
| | A) | Atoms are composed of positively- and negatively-charged subatomic particles. |
| | B) | Zinc sulfide carries a net negative charge. |
| | C) | Atoms are composed of diffuse, evenly distributed positive charges. |
| | D) | Alpha particles are deflected away from gold atoms because of the repulsion of the negatively charged electrons. |
| | E) | The vast majority of the volume of an atom lies outside the nucleus. |
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| 6 | |
Which of the following statements about electron shells and orbitals is incorrect? |
| | A) | Electrons in the outer shell that are available to combine with other atoms are called valence electrons. |
| | B) | Some orbitals are spherical in shape, while others resemble propellers or dumbbells. |
| | C) | A maximum of two electrons can occupy the shell closest to the nucleus. |
| | D) | Shell number 1 is occupied by an s orbital and shell number 2 is occupied by a p orbital. |
| | E) | Electrons in an s orbital are at a lower energy level than electrons in a p orbital. |
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| 7 | |
An atom in the third row and fourth column of the periodic table would have |
| | A) | three electron shells with four electrons in the outer shell. |
| | B) | three electron shells and 1 electron in the outer shell. |
| | C) | two electron shells with three electrons in the outer shell. |
| | D) | very little tendency to react with other atoms. |
| | E) | an atomic mass approximately three times the number of protons. |
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| 8 | |
True or False: Alkaline solutions increase pH by decreasing the concentration of H+ and increasing the concentration of OH-. |
| | A) | True |
| | B) | False |
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| 9 | |
Which one of the following statements about atomic mass is correct? |
| | A) | A Dalton equals 1/12 the mass of a hydrogen atom. |
| | B) | The mass of an object might vary depending on the gravitational pull, but the object's weight remains constant. |
| | C) | One mole of an element with an atomic weight of 20 would equal 20 grams. |
| | D) | 15 N, a "heavy" isotope of nitrogen, has 8 protons and 7 neutrons. |
| | E) | The mass of an atom of carbon is 6.022 x 10 23 g. |
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| 10 | |
Which of the following statements regarding free radicals is incorrect? |
| | A) | Free radicals are composed of an atom with a single electron in its outer shell |
| | B) | Free radicals can be used to fight bacterial infections |
| | C) | Free radicals are neutralized by molecules that can donate electrons without becoming reactive themselves |
| | D) | Free radicals attach themselves to other molecules in order to share an electron. |
| | E) | Free radicals can be formed during radiation exposure |
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| 11 | |
An atom with 4 electrons in its outer shell would likely form how many covalent bonds with other atoms? |
| | A) | 1 |
| | B) | 2 |
| | C) | 3 |
| | D) | 4 |
| | E) | 5 |
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| 12 | |
True or False: Hydrogen bonds are individually weak interactions but collectively can be a significant stabilizing force in macromolecules. |
| | A) | True |
| | B) | False |
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| 13 | |
Why is water described as a polar molecule? |
| | A) | Oxygen is more electronegative than hydrogen, leading to an unequal sharing of electron density. |
| | B) | The hydrogens are always directed up, while the oxygen is oriented down. |
| | C) | The oxygen carries a full negative charge, while the hydrogens each carry half of a positive charge. |
| | D) | The atoms are oriented in a straight line with oxygen at the top, like a totem pole. |
| | E) | At any given moment, the electrons in water are more likely to be found orbiting the hydrogens than the oxygen. |
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| 14 | |
Ions with a net negative charge are called __________, while ions with a net positive charge are called __________. |
| | A) | electrons; protons |
| | B) | anions; cations |
| | C) | acids; bases |
| | D) | cations; anions |
| | E) | polar; nonpolar |
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| 15 | |
Which one of the following statements does not describe a characteristic of chemical reactions in living organisms? Chemical reactions |
| | A) | tend to proceed in a particular direction, but will eventually reach a state of equilibrium. |
| | B) | occur in liquid environments. |
| | C) | do not require an energy source in order to proceed. |
| | D) | require a catalyst to proceed at a biologically relevant rate. |
| | E) | will proceed in either direction depending on changes in free energy. |
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| 16 | |
True or False: If 10 grams of a compound with a molecular mass of 100 is dissolved in 1 L of water, the solution would have a concentration of 0.1 M. |
| | A) | True |
| | B) | False |
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| 17 | |
Molecules with ionized regions at one or more sites and nonpolar regions at other sites are called |
| | A) | hydrophobic. |
| | B) | polar. |
| | C) | bipartite. |
| | D) | hydrophilic. |
| | E) | amphipathic. |
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| 18 | |
Hydrophobic compounds are commonly used in aqueous solutions. |
| | A) | 1)True |
| | B) | 2)False |
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| 19 | |
A chemical reaction in which two or more molecules lose a molecule of water as a result of joining together to form a new molecule is known as a ___________ reaction. |
| | A) | condensation |
| | B) | evaporation |
| | C) | dehydration |
| | D) | hydrolysis |
| | E) | cohesion |
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| 20 | |
True or False: Acid-base buffers contain strong acids and bases which quickly restore pH to the desired range. |
| | A) | True |
| | B) | False |
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| 21 | |
Water forming a droplet is an example of _____________ and the droplet of water adhering to a car windshield is an example of ________________. |
| | A) | adhesion : cohesion |
| | B) | hydrophobic : hydrophilic |
| | C) | hydrogen bonding : covalent bonding |
| | D) | cohesion : adhesion |
| | E) | hydrophilic : hydrophobic |
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