Chapter 2

37) The chemical behavior of an atom is determined by the A) number of protons. B) number of neutrons. C) outermost electron shell. D) size of the atom. E) mass of the nucleus.

C) outermost electron shell.

45) Oxygen (atomic number 8) requires how many additional electrons to fill its outer electron shell? A) 1 B) 2 C) 4 D) 6 E) 8

B) 2

7) The innermost electron shell in an atom holds up to ________ electrons. A) 1 B) 2 C) 4 D) 6 E) 8

B) 2

33) Which of the following is not a cation? A) Na+ B) Cl- C) K+ D) Ca2+ E) Mg2+

B) Cl-

9) By weight, which element is the most plentiful in the human body? A) sulfur B) sodium C) oxygen D) potassium E) carbon

C) oxygen

95) If a substance has a pH that is greater than 7, it is A) neutral. B) acidic. C) alkaline. D) a buffer. E) a salt.

C) alkaline.

22) The actual mass of an atom is known as its A) chemical weight. B) atomic weight. C) atomic mass. D) chemical mass. E) chemical force.

C) atomic mass.

32) H2O is an example of a(n) A) ionic formula. B) glucose molecule. C) compound. D) ion. E) covalent formula.

C) compound.

69) Chemical reactions that yield energy, such as heat, are said to be A) endergonic. B) activated. C) exergonic. D) neutral. E) thermonuclear.

C) exergonic.

52) The three familiar states of matter are solids, liquids, and A) globules. B) fibroids. C) gases. D) crystals. E) vapors.

C) gases.

11) Helium (HE) has an atomic number of 2. It is chemically stable because it A) is neutral in electrical charge. B) readily ionizes to react with other atoms. C) has a full outer electron shell. D) will form a covalent bond with another He atom. E) lacks electrons, thus the He atom is stable.

C) has a full outer electron shell.

79) Nonpolar organic molecules are good examples of A) electrolytes. B) molecules that will dissociate when placed into water. C) hydrophobic compounds. D) hydrophilic compounds. E) solutes.

C) hydrophobic compounds.

87) Molecules that do not readily interact with water are called A) inert. B) stable. C) hydrophobic. D) unstable. E) hydrophilic.

C) hydrophobic.

23) Atoms of the same element whose nuclei contain the same number of protons, but different numbers of neutrons, are called A) isotonics. B) heterotopes. C) isotopes. D) homotopes. E) heterotonics.

C) isotopes.

93) A solution containing equal numbers of hydrogen ions and hydroxide ions is A) acidic. B) basic. C) neutral. D) alkaline. E) in equilibrium.

C) neutral.

6) Isotopes of an element differ in the number of A) protons in the nucleus. B) electrons in the nucleus. C) neutrons in the nucleus. D) electron clouds. E) electrons in energy shells.

C) neutrons in the nucleus.

4) One mole of any element has the same A) mass. B) weight. C) number of atoms. D) number of electrons. E) All of the answers are correct.

C) number of atoms.

73) In living cells, complex metabolic reactions proceed in a series of steps called A) maneuvers. B) degrees. C) pathways. D) increments. E) cascades.

C) pathways.

62) Stored energy that has the ability to do work is called A) kinetic energy. B) heat energy. C) light energy. D) potential energy. E) dark energy.

D) potential energy.

3) The "atomic weight" of an atom reflects the average number of A) protons. B) neutrons. C) electrons. D) protons + neutrons. E) protons + neutrons + electrons.

D) protons + neutrons.

5) The nucleus of an atom consists of A) electrons. B) protons. C) neutrons. D) protons + neutrons. E) protons + electrons.

D) protons + neutrons.

44) Sodium (NA) has an atomic number of 11. How many electrons are in the outer electron shell of a neutral sodium atom? A) 1 B) 2 C) 3 D) 4 E) 8

A) 1

99) Which has the greater concentration of hydrogen ions, a substance with a pH of 5 or a substance with a pH of 4? A) A pH of 4 is greater. B) A pH of 5 is greater. C) They are both equal; 4 and 5 are relative values. D) pH 9, if you mixed the solutions. E) There is not enough information to determine the answer.

A) A pH of 4 is greater.

30) Which of the following statements about hydrogen bonds is false? A) Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively charged atoms. B) Hydrogen bonds can occur within a single molecule. C) Hydrogen bonds can form between neighboring molecules. D) Hydrogen bonds are important for holding large molecules together. E) Hydrogen bonds are responsible for many of the properties of water.

A) Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively charged atoms.

36) In an aqueous solution, sodium ions would move toward A) a negative terminal. B) a positive terminal. C) a pH terminal. D) an organic terminal. E) the bottom.

A) a negative terminal.

65) Collectively, reactions that build new molecules are known as A) anabolic. B) metabolic. C) synthetic reactions. D) exchange reactions. E) catabolic.

A) anabolic.

1) The smallest stable units of matter are A) atoms. B) molecules. C) protons. D) neutrons. E) electrons.

A) atoms.

38) Ions with a + charge are called A) cations. B) anions. C) radicals. D) positrons. E) isotopes.

A) cations.

66) The reaction HCl → H+ + Cl- is what type of reaction? A) decomposition B) exchange C) hydrolysis D) synthesis E) reversible

A) decomposition

85) Soluble inorganic compounds whose solutions will conduct an electric current are called A) electrolytes. B) ions. C) isotopes. D) free radicals. E) metabolites.

A) electrolytes.

18) A(n) ________ is a pure substance composed of atoms of only one kind. A) element B) macromolecule C) ion D) isotope E) compound

A) element

21) Electrons in an atom occupy an orderly series of electron shells or A) energy levels. B) electron clouds. C) energy circles. D) electron lanes. E) energy fields.

A) energy levels.

89) Water has the ability to dissolve polar covalent molecules like sucrose by A) forming hydration spheres around the molecule. B) pulling atoms out of the molecule and into solution. C) creating crystals of positively and negatively charged atoms. D) taking electrons from the polar covalent molecule. E) ionization.

A) forming hydration spheres around the molecule.

63) The energy of motion is A) kinetic energy. B) heat energy. C) light energy. D) potential energy. E) dark energy.

A) kinetic energy.

60) In dehydration synthesis reactions, compounds A) lose water molecules. B) gain water molecules. C) convert water molecules to hydrogen and oxygen. D) convert hydrogen and oxygen to water. E) gain electrons.

A) lose water molecules.

25) The molecule NO is known as A) nitric oxide. B) noxious oxide. C) noxious oxygen. D) nitric oxygen. E) nitrous oxide.

A) nitric oxide.

55) Oxygen, which forms naturally as two atoms, are bonded together with what type of bond? A) nonpolar covalent bond B) single covalent bond C) polar covalent bond D) ionic bond E) hydrogen bond

A) nonpolar covalent bond

91) Which pH is closest to normal body pH? A) pH 7 B) pH 8 C) pH 4 D) pH 3 E) pH 2

A) pH 7

61) Kinetic energy is stored as ________ energy when a spring is stretched or compressed. A) potential B) possible C) plausible D) probable E) positive

A) potential

34) A dust particle floating on a water surface illustrates A) surface tension. B) chemical tension. C) static electricity. D) heat capacity. E) hydrophilic attraction.

A) surface tension.

29) Magnesium atoms have two electrons in the outermost shell. As a result, you would expect magnesium to form ions with a charge of A) +1. B) +2. C) -1. D) -2. E) either +2 or -2.

B) +2.

50) Magnesium atoms have two electrons in the outermost shell and chlorine atoms have seven. The compound magnesium chloride would contain A) 1 magnesium and 1 chlorine. B) 1 magnesium and 2 chlorine. C) 2 magnesium and 1 chlorine. D) 2 magnesium and 7 chlorine. E) impossible to tell without more information

B) 1 magnesium and 2 chlorine.

49) In chemical notation, the symbol Ca2+ means A) two calcium atoms. B) a calcium ion that has lost two electrons. C) a calcium ion that has gained two protons. D) a calcium ion that has gained two electrons. E) a calcium ion that has lost two protons.

B) a calcium ion that has lost two electrons.

40) Ionic bonds are formed when A) atoms share electrons. B) an electron or electrons are completely transferred from one atom to another. C) a pair of electrons is shared unequally by two atoms. D) hydrogen forms bonds with negatively charged atoms. E) two or more atoms lose electrons at the same time.

B) an electron or electrons are completely transferred from one atom to another.

51) Ions with a negative charge are called A) cations. B) anions. C) radicals. D) positrons. E) isotopes.

B) anions.

13) By weight, which element is the second most abundant in the human body? A) oxygen B) carbon C) hydrogen D) nitrogen E) calcium

B) carbon

39) When atoms complete their outer electron shell by sharing electrons, they form A) ionic bonds. B) covalent bonds. C) hydrogen bonds. D) anions. E) cations.

B) covalent bonds.

58) The reaction A + B + energy → AB is an example of a(n) ________ reaction. A) exergonic B) endergonic C) equilibrium D) decomposition E) exchange

B) endergonic

71) Chemical reactions that absorb energy are called A) exergonic. B) endergonic. C) equilibrial. D) decomposition. E) exchange.

B) endergonic.

68) The reaction HCl + NaOH → H2O + NaCl is what type of reaction? A) decomposition B) exchange C) hydrolysis D) synthesis E) reversible

B) exchange

53) A molecule that has unpaired electrons is a(n) A) isotope. B) free radical. C) ion. D) triple bonded molecule. E) compound.

B) free radical.

81) Oppositely charged ions in solution are prevented from combining by A) heat capacity of water. B) hydration spheres. C) water's nonpolar nature. D) free radicals. E) hydrogen bonding.

B) hydration spheres.

27) The molecule H2 is known as A) hydrohydrogen. B) hydrogen. C) hydroxide. D) helium. E) semi-water.

B) hydrogen.

14) In any given molecule, the sum of the atomic weights of its component atoms is called A) molecular mass. B) molecular weight. C) atomic mass. D) atomic weight. E) chemical mass.

B) molecular weight.

8) Radioisotopes have unstable A) ions. B) nuclei. C) isotopes. D) electron clouds. E) protons.

B) nuclei.

77) Compounds that contain carbon as the primary structural atom are called ________ molecules. A) carbonic B) organic C) inorganic D) catabolic E) anabolic

B) organic

31) The molecule O2 is known as A) oxide. B) oxygen. C) organic. D) oxate. E) a salt.

B) oxygen.

100) The ________ of a solution is the negative logarithm of the hydrogen ion concentration expressed in moles per liter. A) charge B) pH C) solubility D) acidity E) basicity

B) pH

90) Which of the following has the highest concentration of hydroxide ions? A) pH 1 B) pH 14 C) pH 7 D) pH 10 E) pH 2

B) pH 14

2) The "atomic number" of an atom is determined by the number of ________ it has. A) electrons B) protons C) neutrons D) protons + neutrons E) protons + electrons

B) protons

88) Muddy lake water is an example of a(n) A) colloid. B) suspension. C) solute. D) solvent. E) solution.

B) suspension.

57) AB → A + B is to decomposition as A + B → AB is to A) exchange. B) synthesis. C) combustion. D) replacement. E) metabolism.

B) synthesis.

43) Ions in an ionic molecule are held together due to A) the sharing of electrons. B) the attraction of opposite electrical charges. C) each electron orbiting all of the ions in the molecule. D) the presence of water molecules. E) the attraction of similar charges of the ions' protons.

B) the attraction of opposite electrical charges.

16) If an isotope of oxygen has 8 protons, 10 neutrons, and 8 electrons, its mass number is A) 26. B) 16. C) 18. D) 8. E) 12.

C) 18.

83) Which of the following statements about water is false? A) It is composed of polar molecules. B) It is responsible for much of the mass of the human body. C) It has a relatively low heat capacity. D) It can dissolve many substances. E) It contains hydrogen bonds.

C) It has a relatively low heat capacity.

94) The chemical notation that indicates concentration is represented as A) (). B) <>. C) [ ]. D) {}. E) ||.

C) [ ].

48) In a molecule of nitrogen, three pairs of electrons are shared by two nitrogen atoms. The type of bond that is formed is an example of a ________ bond. A) single trivalent B) double divalent C) triple covalent D) polar covalent E) hydrogen

C) triple covalent

82) Hydrophilic molecules readily associate with A) lipid molecules. B) hydrophobic molecules. C) water molecules. D) acids. E) salts.

C) water molecules.

59) In hydrolysis reactions, compounds react with A) hydrogen, causing decomposition. B) glucose, causing decomposition. C) water, causing decomposition. D) carbon, causing decomposition. E) water, causing synthesis.

C) water, causing decomposition.

46) The formula for methane gas is CH4. What does the formula 4CH4 represent? A) a molecule with 4 carbon atoms B) a molecule with 4 carbon atoms and 16 hydrogen atoms C) 4 molecules, each containing a carbon and a hydrogen atom D) 4 molecules, each containing a carbon atom and 4 hydrogen atoms E) an inorganic compound with ionic bonds

D) 4 molecules, each containing a carbon atom and 4 hydrogen atoms

76) Which of the following is both an anion and a compound? A) Na+ B) Cl- C) K+ D) HCO3- E) NaCl

D) HCO3-

96) An important buffer in body fluids is A) NaCl. B) NaOH. C) HCl. D) NaHCO3. E) H2O.

D) NaHCO3.

35) In an aqueous solution, cations are attracted toward A) sodium. B) salt. C) buffers. D) anions. E) hydrogen ions.

D) anions.

80) During ionization, water molecules disrupt the ionic bonds of a salt to produce a mixture of ions. These ions can carry a current and so are called A) cations. B) anions. C) acids. D) electrolytes. E) counterions.

D) electrolytes.

20) Electrons whirl around the center of the atom at high speed, forming a(n) A) spiral. B) figure 8. C) cylinder. D) electron cloud. E) helix.

D) electron cloud.

54) Cumulative damage from reactive ________ is thought to be a major factor in aging. A) nitrogen B) double bonds C) isotopes D) free radicals E) helium

D) free radicals

24) The ________ of a radioactive substance is the time required for 50 percent of a given amount of radioisotope to decay. A) decay-point B) mid-life C) deterioration point D) half-life E) entropy

D) half-life

12) Which element commonly has only a proton as its nucleus? A) helium B) neon C) argon D) hydrogen E) carbon

D) hydrogen

28) When electrons are transferred from one atom to another, and the two atoms unite as a result of the opposite charges, a(n) ________ is formed. A) ion B) molecule C) hydrogen bond D) ionic bond E) covalent bond

D) ionic bond

19) The center of an atom is called the A) core. B) hub. C) middle point. D) nucleus. E) focus.

D) nucleus.

41) If a pair of electrons is unequally shared between two atoms, a(n) ________ bond occurs. A) single covalent B) double covalent C) triple covalent D) polar covalent E) hydrogen

D) polar covalent

10) Which of these lists contains only trace elements? A) sulfur, chlorine, oxygen B) selenium, hydrogen, calcium C) boron, oxygen, carbon D) silicon, fluorine, tin E) cobalt, calcium, sodium

D) silicon, fluorine, tin

98) Of the following choices, the pH of the least acidic solution is A) 6.0. B) 4.5. C) 2.3. D) 1.0. E) 12.0.

E) 12.0.

15) Given the following approximate values, calculate the molecular weight for NaCl. Atomic number for Na: 11, Atomic weight for Na: 23 g/mol, Atomic number for Cl: 17,Atomic weight for Cl: 35 g/mol, Boiling point for Cl: -34 °C A) 11 g/mol B) 28 g/mol C) 34 g/mol D) 40 g/mol E) 58 g/mol

E) 58 g/mol

17) If an element is composed of atoms with an atomic number of 6 and a mass number of 14, then a non-isotopic atom of this element contains A) 6 protons. B) 8 electrons. C) 8 neutrons. D) 6 protons and 8 electrons. E) 6 protons and 8 neurons.

E) 6 protons and 8 neurons.

92) An excess of hydrogen ions in the body fluids can have fatal results because this can A) break chemical bonds. B) change the shape of proteins, rendering them nonfunctional. C) disrupt tissue functions. D) change body fluid pH. E) All of the answers are correct.

E) All of the answers are correct.

70) Which of the following descriptors is false regarding enzymes? A) They are proteins. B) They function as biological catalysts. C) They lower the activation energy required for a reaction. D) They affect only the rate of a chemical reaction. E) They are consumed during the reaction.

E) They are consumed during the reaction.

42) Elements that have atoms with full outer shells of electrons A) will form many compounds. B) will normally form anions. C) will normally form cations. D) frequently form hydrogen bonds. E) are inert gases.

E) are inert gases.

75) Each of the following is an inorganic compound except A) water. B) acids. C) bases. D) salts. E) carbohydrates.

E) carbohydrates.

26) The molecule CO2 is known as A) carbonized oxygen. B) carbonated oxygen. C) carbon monoxide. D) carbon oxide. E) carbon dioxide.

E) carbon dioxide.

64) Collectively, reactions that break down molecules are known as A) anabolism. B) metabolism. C) synthesis reactions. D) exchange reactions. E) catabolism.

E) catabolism.

47) In an ionic bond, the electron donor is the ________, whereas the electron acceptor is the ________. A) acid; base B) salt; ion C) anion; cation D) base; acid E) cation; anion Answer: E

E) cation; anion

72) Chemical reactions that occur in the body are accelerated by A) vitamins. B) cofactors. C) hormones. D) electrons. E) enzymes.

E) enzymes.

56) The electrostatic attraction between the slight positive charge of a hydrogen of one molecule and the slight negative charge of an oxygen, nitrogen, or fluorine of another molecule is called a(n) A) nonpolar covalent bond. B) single covalent bond. C) polar covalent bond. D) ionic bond. E) hydrogen bond.

E) hydrogen bond.

78) Compounds that do not usually contain carbon and hydrogen atoms as the primary structural ingredients are called ________ molecules. A) non-carbonic B) organic C) hydro-carbonic D) metabolic E) inorganic

E) inorganic

67) The reaction H2CO3 ↔ H+ + HCO3 is what type of reaction? A) decomposition B) exchange C) hydrolysis D) synthesis E) reversible

E) reversible

86) A(n) ________ is a homogeneous mixture containing a solvent and a solute. A) emulsion B) blend C) compound D) infusion E) solution

E) solution

97) Which of the following substances would be most acidic? A) lemon juice, pH = 2 B) urine, pH = 6 C) tomato juice, pH = 4 D) white wine, pH = 3 E) stomach secretions, pH = 1

E) stomach secretions, pH = 1

74) Activation energy is A) the energy of motion. B) stored energy. C) the same as heat energy. D) the energy in chemical bonds. E) the energy needed to start a reaction.

E) the energy needed to start a reaction.

84) Which property of water helps keeps body temperature stabilized? A) kinetic energy B) lubrication C) surface tension D) reactivity E) thermal inertia

E) thermal inertia