BIOL 1001 Hrincevich Chapter 2 HW/Quiz Questions

The tendency of water molecules to stay together is called __________.

cohesion

A ________ bond is one in which electron pairs are shared.

covalent

A(n) _________________ is a chemical bond in which atoms share a pair of electrons.

covalent bond

A(n) _______ contains the same number of protons, but a different number of neutrons, than another form of the same element.

isotope

A(n) _____ refers to two or more atoms held together by covalent bonds.

molecule

A hydrogen atom with a net positive charge is attracted to an oxygen atom with a net _________ charge.

negative

Copper has 29 protons, 34 neutrons, and 29 electrons. What is the atomic number of copper?

29

Positive ions are more ______ than negative ions. A. Acidic B. Basic

A. Acidic

How many covalent bonds can an atom usually make? A. An atom can make a maximum of four bonds, with each bond consisting of a pair of electrons. B. An atom can make a number of covalent bonds equal to the number of electrons it has in its outer shell. C. An atom can make a number of bonds equal to its charge. D. An atom can make a number of bonds equal to the number of electrons it can donate to another atom. E. An atom can make a number of bonds equal to the number of protons in the nucleus.

A. An atom can make a maximum of four bonds, with each bond consisting of a pair of electrons.

What is the difference between molecules and compounds? A. Molecules may be made from the same type of atoms or different types of atoms. Compounds are molecules made from atoms of different elements. B. Molecules are made from atoms of the same type. C. Compounds are made from atoms of different elements. D. Molecules are made from two atoms. Compounds are made from three or more atoms. E. Compounds are made from atoms. Molecules are made from compounds. F. Molecules are made from atoms. Compounds are made from molecules.

A. Molecules may be made from the same type of atoms or different types of atoms. Compounds are molecules made from atoms of different elements.

Coffee has a pH of 5.0. Stomach acid has a pH of 2.0. How does coffee compare to stomach acid? A. Stomach acid is 1,000 times more acidic than coffee. B. Stomach acid is an acid; coffee is a base. C. Coffee contains fewer OH- ions than stomach acid. D. Coffee contains more H+ ions than stomach acid. E. Coffee is more acidic than stomach acid.

A. Stomach acid is 1,000 times more acidic than coffee.

Why does ice float? A. The hydrogen bonds in solid water force the molecules farther apart from one another than the same bonds in liquid water. B. The hydrogen bonds between molecules of liquid water are stronger than those of the solid, pulling the liquid molecules closer together. C. The energy contained in the hydrogen bonds of ice is greater than the energy contained in the hydrogen bonds of water. D. Solids are less dense in general than their liquid form.

A. The hydrogen bonds in solid water force the molecules farther apart from one another than the same bonds in liquid water.

How does water dissolve salt? A. The partial positive charges of the hydrogen atoms on water surround the negative charge of a chlorine ion. B. The positive charges of the oxygen atoms on water balance the partial negative charge of a sodium atom. C. The partial positive charges of hydrogen form covalent bonds with a negatively charged chloride ion. D. The oxygen atoms of water form a polar covalent bond with the sodium atom. E. The hydrogen atoms of water form hydrogen bonds with a negatively charged chlorine ion.

A. The partial positive charges of the hydrogen atoms on water surround the negative charge of a chlorine ion.

Why does the process of sweating cool off the human body? A. Water has a high heat of vaporization. B. Water can split to form H+ and OH- ions. C. Water has a high specific heat. D. Water can dissolve salt. E. Water avoids the hydrophobic oils on skin.

A. Water has a high heat of vaporization.

In salt, what is the nature of the bond between sodium and chlorine? A. ionic B. hydrophobic C. non-polar covalent D. hydrogen E. polar covalent

A. ionic

What determines the types of chemical reactions that an atom participates in? A. the number of electrons in the outermost electron shell B. its atomic number C. the number of protons it contains D. the number of electrons in the innermost electron shell E. its atomic mass

A. the number of electrons in the outermost electron shell

Which of the following contributes the most toward the ability of water to form hydrogen bonds? A. the polar nature of the water molecule B. the ability of oxygen to bind with a partially charged atom C. the ability of oxygen to bind with hydrogen in a molecule D. the ability of hydrogen to form ionic bonds E. the ability of oxygen to form covalent bonds

A. the polar nature of the water molecule

A buffer consists of undissociated acid (HA) and the ion made by dissociating the acid (A-). How does this system buffer a solution against decreases in pH? A. HA dissociates and releases H+ and A- into solution. B. A- reacts with H+ to become HA. C. As the solution loses H+, HA replaces the lost H+. D. Both A and C. E. None of the above.

B. A- reacts with H+ to become HA.

Because the specific heat of land is less than the specific heat of water, which of the following should be true? A. Land will always be warmer than water. B. After a warm day, the land will cool down quickly, but the water will take longer to cool down. C. Wet dirt should reach higher temperatures than dry dirt. D. Land will reach a higher temperature than water. E. Islands should always be cooler than the mainland.

B. After a warm day, the land will cool down quickly, but the water will take longer to cool down.

Negative ions are more ______ than positive ions. A. Acidic B. Basic

B. Basic

Cancer is caused by DNA mutations. What exactly do cigarette smoke and radiation do that can cause cancer? A. Cigarette smoke damages DNA, leading to free radicals. Radiation causes mutations in DNA. B. Cigarette smoke and radiation both cause free radicals, which damage DNA, leading to mutations. C. Radiation causes free radicals. Cigarette smoke causes DNA damage. D. Cigarette smoke and radiation both cause damage to DNA, leading to mutation.

B. Cigarette smoke and radiation both cause free radicals, which damage DNA, leading to mutations.

How does the way a buffer stabilizes pH during addition of acid differ from the way the same buffer stabilizes pH during addition of base? A. In one case the buffer is strong; in the other case it's weak. B. It's the same reaction running backward or forward. C. In one case it adds H+; in the other case it adds OH-. D. The same buffer can't work for both acid and base.

B. It's the same reaction running backward or forward.

What force holds a molecule of HCl together in an ionic bond? A. polarity B. electrical attraction C. partial charges D. electron sharing E. hydrogen bonding

B. electrical attraction

In a neutral solution the concentration of _____. A. water molecules is less than the concentration of hydrogen ions B. hydrogen ions is equal to the concentration of hydroxide ions C. hydrogen ions is less than the concentration of hydroxide ions D. water molecules is less than the concentration of hydroxide ions E. hydrogen ions is greater than the concentration of hydroxide ions

B. hydrogen ions is equal to the concentration of hydroxide ions

What subatomic particle (s) can be found in the nucleus of the atom? A. protons B. protons and neutrons C. neutrons and electrons D. neutrons and atoms E. protons and electrons F. neutrons

B. protons and neutrons

Which of these effects results from the hydrogen bonding between water molecules and nothing else? A. water adhering to surfaces B. water acting as an acid C. water traveling up a tree D. water having surface tension E. water acting as a solvent

D. water having surface tension

Which statement is true of pH buffers? A. They consist of strong acids and strong bases. B. They keep the pH of the blood constant. C. They consist of weak acids and weak bases. D. Both A and B. E. Both B and C.

C. They consist of weak acids and weak bases.

Which of the following lists of terms is in the correct order of size, going from smallest to largest? A. nucleus, electron, proton, atom, molecule B. electron, proton, nucleus, molecule, atom C. electron, proton, nucleus, atom, molecule D. molecule, atom, nucleus, proton, electron E. proton, electron, nucleus, atom, molecule

C. electron, proton, nucleus, atom, molecule

A phrase that applies to covalent bonding and not other kinds of bonds is ... A. charge attraction. B. great strength. C. electron-sharing. D. paired electrons. E. All of the above.

C. electron-sharing.

In which scenario below will the electrons have the highest energy? A. electrons in the outer shell of helium B. electrons in the outer shell of oxygen C. electrons in the outer shell of potassium D. electrons in the outer shell of carbon E. electrons in the outer shell of nitrogen F. electrons in the outer shell of sulfur

C. electrons in the outer shell of potassium (The last electron of potassium occupies the high-energy fourth shell.)

In water, the chemicalHCO3 - acts as a buffer. In dry form, this chemical is often ionically bound to another element. Which of the following elements would be a good candidate for that element? A. chlorine (Cl) B. oxygen (O) C. sodium (Na+) D. hydroxide (OH) E. carbon (C)

C. sodium (Na+)

Which answer helps to explain why all living cells need pH buffers? A. ATP will not deliver energy if it is ionized. B. Hydrogen bonds only form at medium pH values. C. Nucleic acids must have positive charges to form double helices. D. Amino acid side chains have many carboxyl and amino groups.

D. Amino acid side chains have many carboxyl and amino groups.

How are ionic and covalent bonds related? A. Ionic bonds are harder to break apart than covalent bonds. B. Ionic bonds result in positive charges. Covalent bonds result in negative charges. C. Electrons are shared in an ionic bond and traded completely in a covalent bond. D. Ionic and covalent bonds both result in a full outer electron shell. E. Ionic bonds involve electrons. Covalent bonds involve the nucleus.

D. Ionic and covalent bonds both result in a full outer electron shell.

Consider a molecule formed entirely of carbon and hydrogen atoms covalently bound together. What properties might this molecule have? A. The molecule would act as a polar solvent. B. This molecule would have a high specific heat. C. The molecule would make hydrogen bonds with other like molecules. D. The molecule would be non-polar. E. The molecule would be ionic.

D. The molecule would be non-polar.

An ionic bond involves _____. A. the unequal sharing of an electron pair B. the sharing of a single pair of electrons C. water avoidance D. an attraction between ions of opposite charge E. no atoms other than sodium and chlorine

D. an attraction between ions of opposite charge

Atoms with the same number of protons but with different electrical charges _____. A. have different numbers of neutrons B. have different atomic numbers C. are different isotopes D. are different ions E. have different atomic masses

D. are different ions

To make a buffer, you need to ... A. combine equal amounts of a strong acid and a strong base in water. B. put either a strong acid or a strong base in water. C. adjust the pH to 7.0. D. have a weak acid or a weak base half ionized in water. E. Both A and C.

D. have a weak acid or a weak base half ionized in water.

Which of these atoms will be inert? A. nitrogen (7 electrons) B. chlorine (17 electrons) C. sodium (11 electrons) D. neon (10 electrons) E. magnesium (12 electrons)

D. neon (10 electrons) (Neon has eight electrons in its outer shell. It is also an example of a Noble gas and inert (unreactive))

What is the fundamental structural unit of an element? A. the molecule B. the electron C. the neutron D. the atom E. the proton

D. the atom

Which basic property of a single water molecule accounts for all of its special features, including adhesion and cohesion, its ability to act as a solvent, and its high specific heat? A. the density of water B. the hydrogen bonding of water C. the ionic character of water D. the polar nature of water E. the oxygen in water

D. the polar nature of water

Why are hydrophobic molecules such as fats and oils unable to dissolve in watery solutions? A. Hydrophobic molecules have polar covalent bonds, preventing water from interacting with them. B. Water molecules interact only with ionic bonds, not covalent bonds. C. Hydrophobic molecules attract water molecules and form a weak bond. D. Hydrophobic molecules form hydrogen bonds with each other, excluding water. E. Hydrophobic molecules are nonpolar, so they can't form hydrogen bonds with water. Water molecules form hydrogen bonds with each other, excluding the hydrophobic molecules.

E. Hydrophobic molecules are non-polar, so they can't form hydrogen bonds with water. Water molecules form hydrogen bonds with each other, excluding the hydrophobic molecules.

Sugar is a covalently linked compound with many atoms. Water is able to dissolve sugar. What does this suggest about the atoms of sugar? A. Sugar contains hydrophobic atoms. B. Sugar contains ions. C. Sugar contains carbon. D. Sugar contains hydrogen. E. Sugar must contain oxygen or nitrogen atoms, which can form polar bonds

E. Sugar must contain oxygen or nitrogen atoms, which can form polar bonds

If electrons in water molecules were equally attracted to the hydrogen and oxygen atoms, how would this affect the polar covalent bonds between the hydrogen and oxygen atoms? A. The bond would break. B. The bond would become more polar. C. The bond would become a hydrogen bond. D. The bond would become covalent. E. The bond would become less polar. F. The bond would become ionic.

E. The bond would become less polar.

How do the hydrogen bonds between water molecules compare to the covalent bonds within water molecules? A. Hydrogen bonds are between two hydrogen atoms. B. Covalent bonds are between a hydrogen and an oxygen. C. The hydrogen and covalent bonds both involve electron sharing. D. The hydrogen and covalent bonds are both polar. E. The hydrogen bonds are more easily broken than the covalent bonds.

E. The hydrogen bonds are more easily broken than the covalent bonds.

Which of these relationships is true of an uncharged atom? A. The atomic mass is equal to the atomic number. B. The number of electrons is equal to the number of neutrons. C. The number of neutrons is equal to the number of protons. D. The atomic mass is equal to the number of electrons. E. The number of protons is equal to the number of electrons.

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

Which of these refers to atoms with the same atomic number but different atomic masses? A. These atoms are different elements. B. These atoms have different numbers of electrons. C. These atoms have different numbers of protons. D. These atoms are isomers. E. These atoms are isotopes.

E. These atoms are isotopes.

What is a hydrogen bond? A. a bond between the hydrogen and oxygen within a water molecule B. a weak bond between a slightly positive hydrogen atom and a slightly negative atom in a neighboring molecule C. a polar bond between two hydrogen atoms in the same water molecule D. a weak bond between the hydrogen atoms in two different water molecules E. a weak bond between two slightly positively charged hydrogen atoms F. a polar covalent bond between hydrogen and oxygen

E. a weak bond between two slightly positively charged hydrogen atoms

Buffers work best when ... A. 5% nearly all of the buffer molecules are dissociated. B. the ratio of H+ to OH- is close to 1.0. C. nearly all of the buffer molecules are undissociated. D. the pH is nearly neutral. E. about half of the buffer molecules are dissociated.

E. about half of the buffer molecules are dissociated.

What name is given to the bond between water molecules? A. ionic B. single (non-polar) covalent C. hydrophobic D. polar covalent E. hydrogen

E. hydrogen

What type of bond joins the carbon atom to each of the hydrogen atoms? A. polar covalent B. hydrogen C. double (nonpolar) covalent D. ionic E. single (nonpolar) covalent

E. single (nonpolar) covalent

What is specific heat? A. the temperature of a substance at 1°C B. the energy present in water at 1°C C. the energy required to cool water to 1°C D. the energy required to melt ice E. the energy necessary to raise the temperature of a substance by 1°C F. the energy required to evaporate water

E. the energy necessary to raise the temperature of a substance by 1°C

What property of an atom determines which element it is? A. the number of neutrons B. the number of electrons C. the number of atoms D. the number of molecules E. the number of protons

E. the number of protons

How do atoms respond when they absorb energy? A. Protons and neutrons leave the nucleus. B. Neutrons leave the nucleus. C. Electrons vibrate faster. D. The nucleus vibrates. E. Electrons emit light. F. Electrons move to a higher orbital.

F. Electrons move to a higher orbital.

Which part of the atom participates in a chemical bond? A. all electrons and some protons B. all the protons and neutrons in the atom C. all electrons in the atom D. protons in the outer shell E. all the protons in the atom F. electrons in the outer shell

F. electrons in the outer shell

Hydrogen ion

H+

____________ compounds will interact with water.

Hydrophilic

_________ compounds do not interact with water.

Hydrophobic

A(n) __________ is a subatomic particle found in an atom's nucleus that has no electrical charge.

Neutron

Hydroxide ion

OH-