Unit 1 Questions

Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom? A) 1 B) 3 C) 5 D) 7 E) 9

A

Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion concentration of this lake? A) 1 × 10-10 mol of hydroxyl ion per liter of lake water B) 1 × 10-4 mol of hydroxyl ion per liter of lake water C) 10.0 M with regard to hydroxyl ion concentration D) 4.0 M with regard to hydroxyl ion concentration E) both B and D

A) 1 × 10-10 mol of hydroxyl ion per liter of lake water

Which of the following best describes chemical equilibrium? A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products. B) Concentrations of products are higher than the concentrations of the reactants. C) Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products. D) Reactions stop only when all reactants have been converted to products. E) There are equal concentrations of reactants and products, and the reactions have stopped.

A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products.

One of the following people set up a closed system to mimic Earthʹs early atmosphere and discharged electrical sparks through it. A variety of organic compounds common in organisms were formed. Who did this? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé

A) Stanley Miller

Which statement is true of all atoms that are anions? A) The atom has more electrons than protons.B) The atom has more protons than electrons. C) The atom has fewer protons than does a neutral atom of the same element. D) The atom has more neutrons than protons. E) The net charge is 12.

A) The atom has more electrons than protons.

Which of the following statements correctly describes geometric isomers? A) They have variations in arrangement around a double bond. B) They have an asymmetric carbon that makes them mirror images. C) They have the same chemical properties.D) They have different molecular formulas. E) Their atoms and bonds are arranged in different sequences.

A) They have variations in arrangement around a double bond.

Which of the following is not considered to be a weak molecular interaction? A) a covalent bond B) a van der Waals interactionC) an ionic bond in the presence of water D) a hydrogen bond E) A and B only

A) a covalent bond

Sometimes atoms form molecules by sharing two pairs of valence electrons. When this occurs, the atoms are said to be joined by A) a double covalent bond. B) an electronegative bond. C) a hydrogen bond. D) a protonic bond. E) a complex bond.

A) a double covalent bond.

Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that A) an electron may move to an electron shell farther out from the nucleus. B) an electron may move to an electron shell closer to the nucleus. C) the atom may become a radioactive isotope.D) the atom would become a positively charged ion, or cation. E) the atom would become a negatively charged ion, or anion.

A) an electron may move to an electron shell farther out from the nucleus.

Which of the following solutions has the greatest concentration of hydrogen ions [H +]? A) gastric juice at pH 2 B) vinegar at pH 3C) tomato juice at pH 4 D) black coffee at pH 5 E) household bleach at pH 12

A) gastric juice at pH 2

What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-12 M? A) pH 2 B) pH 4 C) pH 10 D) pH 12 E) pH 14

A) pH 2

The hybrid orbitals in a molecule of methane are orientedA) toward the corners of a tetrahedron centered on the carbon atom. B) toward the corners of a cube centered on the carbon atom.C) toward the corners of a triangle centered on the carbon atom. D) toward the corners of a rectangle centered on the carbon atom. E) toward the edges of an oval centered on the carbon atom.

A) toward the corners of a tetrahedron centered on the carbon atom.

If the pH of a solution is decreased from 9 to 8, it means that theA) concentration of H+ has decreased to one-tenth (1/10) what it was at pH 9. B) concentration of H+ has increased 10-fold (10X) compared to what it was at pH 9. C) concentration of OH- has increased 10-fold (10X) compared to what it was at pH 9. D) concentration of OH- has decreased to one-tenth (1/10) what it was at pH 9. E) Both B and D are correct.

Answer: E

What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen? A) 1 B) 2 C) 3 D) 4 E) 6

B) 2

What is the maximum number of electrons in the 1s orbital of an atom? A) 1 B) 2 C) 3 D) 4 E) 5

B) 2

What is the valence of an atom with six electrons in its outer electron shell? A) 1 B) 2 C) 3 D) 4 E) 5

B) 2

If an atom of sulfur (atomic number 16) were allowed to react with atoms of hydrogen (atomic number 1), which of the molecules below would be formed? A) S-H B) H-S-H C) H-S-H | H D) H | H-S-H | H E) H=S=H

B) H-S-H

Which of the following ionizes completely in solution and is considered to be a strong acid? A) NaOH B) HCl C) NH3 D) H2CO3E) CH3COOH

B) HCl

Thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occur as enantiomers, or molecules that A) have identical three-dimensional shapes. B) are mirror images of one another. C) lack an asymmetric carbon.D) differ in the location of their double bonds. E) differ in their electrical charge.

B) are mirror images of one another.

Van der Waals interactions result when A) hybrid orbitals overlap. B) electrons are not symmetrically distributed in a molecule. C) molecules held by ionic bonds react with water.D) two polar covalent bonds react. E) a hydrogen atom loses an electron.

B) electrons are not symmetrically distributed in a molecule.

Organic chemistry is currently defined asA) the study of compounds made only by living cells. B) the study of carbon compounds.C) the study of vital forces.D) the study of natural (as opposed to synthetic) compounds. E) the study of hydrocarbons.

B) the study of carbon compounds.

What is the hydroxide ion concentration of the lake described in question 7? A) 10-7 M B) 10-4 M C) 10-10 M D) 10-14 M E) 10 M

C) 10-10 M

Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake? A) 4.0 MB) 10-10 M C) 10-4 M D) 104 M E) 4%

C) 10-4 M

Equal volumes of vinegar from a freshly-opened bottle are added to each of the following solutions. After complete mixing, which of the mixtures will have the highest pH? A) 100 mL of pure waterB) 100 mL of freshly-brewed coffee C) 100 mL of household cleanser containing 0.5M ammonia D) 100 mL of freshly-squeezed orange juice E) 100 mL of tomato juice

C) 100 mL of household cleanser containing 0.5M ammonia

A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50 -L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.) A) 50°C B) 5°C C) 10°C D) 100°C E) 1°C Answer: C

C) 10°C

You have a freshly-prepared 0.1M solution of glucose in water. Each liter of this solution contains how many glucose molecules? A) 6.02 × 1023 B) 3.01 × 1023 C) 6.02 × 1024 D) 12.04 × 1023 E) 6.02 × 1022

C) 6.02 × 1024

23) How many grams of the molecule in Figure 3.2 would be equal to 1 mol of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1) (2 carbon, 2 oxygen, 4 hydrogen) A) 29 B) 30 C) 60 D) 150 E) 342

C) 60

The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound: A) HS B) HS2 C) H2S D) H3S2 E) H4S

C) H2S

Which two functional groups are always found in amino acids? A) ketone and aldehyde B) carbonyl and carboxylC) carboxyl and aminoD) phosphate and sulfhydryl E) hydroxyl and aldehyde

C) carboxyl and amino

Which functional groups can act as acids? A) amine and sulfhydryl B) carbonyl and carboxyl C) carboxyl and phosphate D) hydroxyl and aldehyde E) ketone and amino

C) carboxyl and phosphate

Which of the following results from a transfer of electron(s) between atoms? A) nonpolar covalent bond B) polar covalent bond C) ionic bondD) hydrogen bond E) hydrophobic interaction

C) ionic bond

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their A) mass in daltons. B) mass in grams.C) number of molecules. D) number of atoms. E) volume.

C) number of molecules

How do isotopes of the same element differ from each other? A) number of protons B) number of electronsC) number of neutronsD) valence electron distribution E) amount of radioactivity

C) number of neutrons

A covalent chemical bond is one in which A) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. B) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms. C) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms. D) outer-shell electrons of one atom are transferred to the inner electron shells of another atom. E) the inner-shell electrons of one atom are transferred to the outer shell of another atom.

C) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms.

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by A) hydrogen bonds. B) nonpolar covalent bonds. C) polar covalent bonds.D) ionic bonds. E) van der Waals interactions.

C) polar covalent bonds.

16) The two molecules shown in Figure 4.1 (same amount of molecules but in different shape) are best described as A) optical isomers. B) radioactive isotopes.C) structural isomers.D) nonradioactive isotopes. E) geometric isomers.

C) structural isomers.

Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon? A) the change in density when it condenses to form a liquid or solid B) reactions with other atmospheric compounds C) the release of heat by the formation of hydrogen bonds D) the release of heat by the breaking of hydrogen bonds E) the high surface tension of water

C) the release of heat by the formation of hydrogen bonds

How many grams of the molecule in Figure 3.2 would be required to make 2.5 L of a 1 M solution of the molecule?(Carbon = 12, Oxygen = 16, Hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342

D) 150

A molecule of carbon dioxide (CO2) is formed when one atom of carbon (atomic number 6) is covalently bonded with two atoms of oxygen (atomic number 8). What is the total number of electrons that must be shared between the carbon atom and the oxygen atoms in order to complete the outer electron shell of all three atoms? A) 1 B) 2 C) 3 D) 4 E) 5

D) 4

How many grams of acetic acid (C2H4O2) would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.) A) 10.0 g B) 0.1 g C) 6.0 g D) 60.0 g E) 0.6 g

D) 60.0 g

Which of the following explains most specifically the attraction of water molecules to one another? A) nonpolar covalent bond B) polar covalent bond C) ionic bondD) hydrogen bond E) hydrophobic interaction

D) Hydrogen bond

Which of the following is a false statement concerning amino groups? A) They are basic in pH. B) They are found in amino acids. C) They contain nitrogen.D) They are nonpolar. E) They are components of urea.

D) They are nonpolar.

What is the name of the functional group shown in Figure 4.4? A) carbonyl B) ketone C) aldehyde D) carboxyl E) hydroxyl (carbon double bonded to oxygen, bonded to oxygen which is bonded to hydrogen.

D) carboxyl

Which type of bond must be broken for water to vaporize? A) ionic bonds B) nonpolar covalent bonds C) polar covalent bondsD) hydrogen bonds E) covalent bonds

D) hydrogen bonds

What is the pH of a solution with a hydrogen ion [H+] concentration of 10-8 M? A) pH 2 B) pH 4 C) pH 6 D) pH 8 E) pH 10

D) pH 8

One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+ If the pH of the blood drops, one would expect A) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-. B) the concentration of hydroxide ion (OH-) to increase. C) the concentration of bicarbonate ion (HCO3-) to increase. D) the HCO3- to act as a base and remove excess H+ with the formation of H2CO3. E) the HCO3- to act as an acid and remove excess H+ with the formation of H2CO3.

D) the HCO3- to act as a base and remove excess H+ with the formation of H2CO3.

How many molecules of glycerol (C3H8O3) would be present in 1 L of a 1 M glycerol solution? A) 1 B) 14 C) 92 D) 1 × 107E) 6.02 × 10^23

E) 6.02 × 10^23

One mole (mol) of a substance is A) 6.02 × 1023 molecules of the substance.B) 1 g of the substance dissolved in 1 L of solution. C) the largest amount of the substance that can be dissolved in 1 L of solution. D) the molecular mass of the substance expressed in grams. E) A and D only

E) A and D only

Which of the following statements best describes the carbon atoms present in all organic molecules? A) They were incorporated into organic molecules by plants. B) They were processed into sugars through photosynthesis. C) They are ultimately derived from carbon dioxide. D) Only A and C are correct. E) A, B, and C are correct.

E) A, B, and C are correct.

Which of the following would be regarded as compounds? A) H2 B) H2O C) O2 D) CH4 E) B and D, but not A and C

E) B and D, but not A and C

Buffers are substances that help resist shifts in pH by A) releasing H+ in acidic solutions. B) donating H+ to a solution when they have been depleted. C) releasing OH- in basic solutions. D) accepting H+ when the are in excess. E) Both B and D are correct.

E) Both B and D are correct.

Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that A) solution Y has no free hydrogen ions (H+). B) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen ions in solution Y. C) the concentration of hydrogen ions in solution Y is 1,000 times as great as the concentration of hydrogen ions in solution X. D) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y. E) None of the other answer choices correctly describes these solutions.

E) None of the other answer choices correctly describes these solutions.

Which of the following statements is false? A) Atoms of the various elements differ in their number of subatomic particles. B) All atoms of a particular element have the same number of protons in their nuclei. C) The neutrons and protons present in the nucleus of an atom are almost identical in mass; each has a mass of about 1 dalton. D) An atom is the smallest unit of an element that still retains the properties of the element. E) Protons and electrons are electrically charged particles. Protons have one unit of negative charge, and electrons have one unit of positive charge.

E) Protons and electrons are electrically charged particles. Protons have one unit of negative charge, and electrons have one unit of positive charge.

Which is the best description of a carbonyl group?A) an oxygen joined to a carbon by a single covalent bond B) a nitrogen and two hydrogens joined to a carbon by covalent bonds C) a carbon joined to two hydrogens by single covalent bondsD) a sulfur and a hydrogen joined to a carbon by covalent bonds E) a carbon atom joined to an oxygen by a double covalent bond

E) a carbon atom joined to an oxygen by a double covalent bond

The experimental approach taken in current biological investigations presumes that A) simple organic compounds can be synthesized in the laboratory from inorganic precursors, but complex organic compounds like carbohydrates and proteins can only be synthesized by living organisms. B) a life force ultimately controls the activities of living organisms and this life force cannot be studied by physical or chemical methods. C) although a life force, or vitalism, exists in living organisms, this life force cannot be studied by physical or chemical methods. D) living organisms are composed of the same elements present in nonliving things, plus a few special trace elements found only in living organisms or their products. E) living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena.

E) living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena.

Testosterone and estradiol are A) nucleic acids. B) carbohydrates. C) proteins.D) phospholipids. E) steroids.

E) steroids.

Enantiomers

Substances that are isomers but can have opposite physiological effects.

You have a freshly-prepared 1M solution of glucose in water. You carefully pour out a 100 mL sample of that solution. How many glucose molecules are included in that 100 mL sample? A) 6.02 × 1023 B) 3.01 × 1023 C) 6.02 × 1024 D) 12.04 × 1023 E) 6.02 × 1022

c