BIO 1361 Chemistry Review

Examples of adhesion

Water molecules cling to plant cell walls. Water molecules cling to the side of a beaker.

Polar attractions are ... (a) forces between atoms with partial charges. (b) weaker than covalent bonds. (c) important because they are numerous. (a) and (b) are true. (c) is false. (a), (b), and (c) are correct.

(a), (b), and (c) are correct.

What is the mass number of an ion with 105 electrons, 159 neutrons, and a +1 charge?

265

Examples of surface tension

A sewing needle floats when it is placed gently on top of water in a bucket. A water strider runs across a pond without breaking the surface.

Examples of cohesion

Water molecules are attracted to each other. A drop of water spilled on a table forms a drop on the table, rather than spreading out over the surface.

The innermost electron shell of an atom can hold up to _____ electrons. a. 2 b. 8 c. 32 d. 18 e. 1

a. 2

What does the term electron orbital describe? a. An electron orbital describes a three-dimensional space where an electron can be found 90% of the time. b. An electron orbital describes the exact distance of an electron from the nucleus. c. An electron orbital describes the orbit of an electron around the nucleus.

a. An electron orbital describes a three-dimensional space where an electron can be found 90% of the time.

Which answer correctly ranks the atoms in terms of decreasing electronegativity (the highest electronegativity first)? a. O, N, C, H b. N, O, H, C c. N, O, C, H d. O, N, H, C e. C, H, O, N

a. O, N, C, H

Dr. Haxton says the O-O bond is polar and the C-C bond is nonpolar. A good student would say ... a. Wrong again, Ralph. Both bonds are nonpolar. b. No, both bonds are highly polar. c. No way. C is more electronegative than O. d. Yes. O attracts electrons more strongly than C. e. Right! O is electronegative, so O2 is polar.

a. Wrong again, Ralph. Both bonds are nonpolar.

Which of the following allows for the creation of heat and friction around Enceladus? a. gravity b. volcanic explosions c. decomposition d. a black hole

a. gravity

You discover a new moon orbiting Saturn. It has liquid water, energy, and carbon. Which essential ingredient for life as we know it is missing? a. nitrogen b. hydrogen c. sodium d. oxygen

a. nitrogen

A carbon atom and a hydrogen atom form what type of bond in a molecule? a. nonpolar covalent bond b. ionic bond c. Van der Waals interaction d. hydrogen bond e. polar covalent bond

a. nonpolar covalent bond

What is the difference between 12C and 13C? a. 12C has one less proton than 13C. b. 12C has one less neutron than 13C c. 12C can form four covalent bonds and 13C only forms three d. 12C always forms nonpolar covalent bonds with hydrogen, whereas 13C forms polar covalent bonds.

b. 12C has one less neutron than 13C

If you want a molecule that is highly polar, look for one that contains: a. S-H b. H-N c. C-S d. O-N e. C-H

b. H-N

An element in the second row of the periodic table that has four valence electrons would most likely _____. a. form ionic bonds b. form four covalent bonds c. be more electronegative than an element with six valence electrons in the same row of the periodic table d. have a full outer shell and be unreactive

b. form four covalent bonds

If a hydrogen atom gains an electron then _____. a. it becomes an isotope b. it acquires a negative charge c. its atomic number changes d. its mass number changes

b. it acquires a negative charge

What happens when two atoms form a chemical bond? a. A chemical bond forms when two atoms transfer or share protons to achieve a stable nucleus. b. Two atoms fuse together to form a chemical bond. c. A chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells.

c. A chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells.

Why does a lake freeze from the top down instead of from the bottom up? a. Liquid water is less dense than ice. b. Liquid water and ice have the same density. c. Liquid water is more dense than ice. d. Liquid water lacks density.

c. Liquid water is more dense than ice.

For CO2, which statement is correct? See Section 2.1 (Page 57) . a. The carbon atom has a partial negative charge; both oxygen atoms have a partial positive charge. b. The molecule has a bent structure. c. The carbon atom has a partial positive charge; both oxygen atoms have a partial negative charge. d. The molecule contains two triple bonds.

c. The carbon atom has a partial positive charge; both oxygen atoms have a partial negative charge.

If a reaction is exothermic, then which of the following statements is always true? a. Energy must be added for the reaction to proceed. b. It occurs extremely quickly. c. The products have lower potential energy than the reactants. d. The products have lower entropy (are more ordered) than the reactants.

c. The products have lower potential energy than the reactants.

Which of these refers to atoms with the same atomic number but different atomic masses? a. These atoms have different numbers of protons. b. These atoms have different numbers of electrons. c. These atoms are isotopes. d. These atoms are different elements. e. These atoms are isomers.

c. These atoms are isotopes.

Which of the following bonds can form between atoms of equal electronegativity? a. Ionic bonds can form between atoms of equal electronegativity. b. Hydrogen bonds can form between atoms of equal electronegativity. c. Van der Waals interactions can form between atoms of equal electronegativity.

c. Van der Waals interactions can form between atoms of equal electronegativity.

Which statement about weak bonds is correct? a. Weak chemical bonds form only between atoms of similar electronegativity. b. Weak bonds are less important to living things than strong covalent bonds. c. Weak bonds are transient and easily reversible.

c. Weak bonds are transient and easily reversible.

Hydrogen bonds ... a. are covalent bonds. b. share electrons between the two bonded atoms. c. can form between H and N. d. occur within a water molecule. e. All of the above.

c. can form between H and N.

What determines the types of chemical reactions that an atom participates in? a. its atomic mass b. its atomic number c. the number of electrons in the outermost electron shell d. the number of electrons in the innermost electron shell e. the number of protons it contains

c. the number of electrons in the outermost electron shell

Use your knowledge of electronegativity to pick out the most polar bond in the list below. a. N-H b. C-H c. O-N d. O-H e. O-C

d. O-H

An ionic bond is formed when _____. a. atoms are subjected to radioactive isotopes b. both atoms are equally attractive to electrons c. both atoms are nonpolar d. one atom transfers an electron to another atom e. both atoms are electrically neutral

d. one atom transfers an electron to another atom

The reactivity of an atom arises from _____. a. the potential energy of the valence shell. b. the energy difference between the s and p orbitals. c. the sum of the potential energies of all the electron shells. d. the existence of unpaired electrons in the valence shell. e. the average distance of the outermost electron shell from the nucleus.

d. the existence of unpaired electrons in the valence shell.

The type of bonding and the numbers of covalent bonds an atom can form with other atoms is determined by _____. a. the nucleus b. the number of protons c. the number of neutrons d. the number of unpaired electrons in the valence shell e. the size of the atom; smaller atoms are chemically more reactive

d. the number of unpaired electrons in the valence shell

Hydrogen bonding is most often seen _____. a. if the molecule consists of three or fewer atoms b. when multiple carbon atoms are present c. in molecules whose three-dimensional shape is tetrahedral d. when hydrogen is covalently bonded to an electronegative atom e. when the bonds within the molecule are nonpolar covalent bonds

d. when hydrogen is covalently bonded to an electronegative atom

Which statement is true of all atoms that are anions? a. The atom has fewer protons than does a neutral atom of the same element. b. The atom has more neutrons than protons. c. The net charge is 1-. d. The atom has more protons than electrons. e. The atom has more electrons than protons.

e. The atom has more electrons than protons.

Which of these relationships is true of an uncharged atom? a. The atomic mass is equal to the number of electrons. b. The atomic mass is equal to the atomic number. c. The number of neutrons is equal to the number of protons. d. The number of electrons is equal to the number of neutrons. e. The number of protons is equal to the number of electrons.

e. The number of protons is equal to the number of electrons.