chapter 2 (Bio 121)

. Nitrogen has a higher electronegativity than hydrogen. As a result you would expect that ammonia (NH3) molecules can form ____ with each other. A. hydrogen bonds B. ionic bonds C. covalent bonds D. hydrophilic bonds E. cohesive bonds

A

All atoms tend to fill their outer energy levels with the maximum number of electrons, usually eight. Depending on whether atoms satisfy the octet rule will predict: A. the chemical behavior of the atoms. B. whether they will be found in nature. C. whether they will dissolve in water. D. their radioactive energy.

A

Atoms of a single element that possess different numbers of neutrons are called: A. ions. B. monomers. C. isomers. D. isotopes. E. polymers.

D

Carbon has 4 valence electrons and oxygen has 6. The molecule of Carbon dioxide would contain _____. A. hydrogen bonds B. two covalent bonds C. ionic bonds D. one covalent bond

D

Consider the following electronegativity values: Boron (B) = 1.8 Carbon (C) = 2.5 Chlorine (Cl) = 3.2 Selenium (Se) = 2.6 Which of the following bonds is the most polar? A. Se-Cl B. cannot determine from the information provided C. C-Cl D. B-Cl

D

To increase the rate of a reaction you could: A. Add more products. B. Decrease the temperature. C. Add more reactants. D. Add more catalyst.

C

-*60. Your sump-pump is not working. You don't replace it right away. Next day you go to the basement and realize that the basement floor and carpeting is damp. You realize that water must have wicked into the carpet from the floor by ______. A. adhesion, cohesion, and solubility B. adhesion, cohesion and surface tension C. adhesion and solubility D. cohesion and adhesion

B

. Cl + e- ® Cl- is an example of a: A. oxidation. B. reduction. C. ionization. D. polymerization.

B

. If water does not form hydrogen bonds, at room temperatures this water would be _____. A. a solid B. a gas C. a liquid

B

. Oxygen-16 is abundant and has 8 protons and 8 neutrons. Oxygen-18 has two extra neutrons. These two forms are: A. oxygen dimers. B. oxygen isotopes. C. oxygen isomers. D. oxygen ions.

B

. Sodium has 11 electrons arranged in three energy levels. In order to become stable, sodium form an ion with: A. -1 charge. B. +1 charge. C. no charge. D. +8 charge. E. -8 charge.

B

A chemist adds a chemical to pure water and there is a 1000 fold increase in the concentration of hydrogen ions. What is the best approximation of the new pH value? A. 0 B. 5 C. 7 D. 4 E. 9

B

All atoms possess the ability to do work. The term that is defined as the ability to do work is: A. matter B. energy C. molecules D. space

B

An atom that is negatively charged because it has accepted an electron is a(n): A. isotope. B. ion. C. monomer. D. isomer.

B

Atoms in which the number of electrons does not equal the number of protons are known as: A. valences. B. ions. C. isotopes. D. isomers.

B

Bicarbonate ions in the blood can absorb hydrogen ions, keeping pH balanced. Bicarbonate is acting as a ____ in blood. A. base B. buffer C. alkaline D. acid

B

Carbon-12, Carbon-13 and Carbon-14 are examples of: A. isomers B. isotopes C. ions D. molecules

B

Magnesium chloride is a salt formed with ionic bonds between one magnesium ion and two chloride ions. Magnesium has two electrons in its outer shell and chlorine has seven electrons in its outer shell. How are the electrons transferred between these atoms? A. Chlorine is oxidized and magnesium is reduced. B. Magnesium is oxidized and chlorine is reduced. C. Both magnesium and chlorine are oxidized. D. Both magnesium and chlorine are reduced.

B

Organisms are composed of molecules, which are collections of smaller units, termed: A. monomers. B. atoms. C. electrons. D. polymers. E. ions.

B

Sugars dissolve well in water because of water's ______. A. ionic bonds B. polarity C. cohesiveness D. hydrophobic exclusion

B

The carbonic acid and bicarbonate buffer in blood is extremely important to help maintain homeostasis. What would happen to the pH of the blood if bicarbonate were removed? A. Removing bicarbonate from the blood would increase the pH B. Removing bicarbonate from the blood would decrease the pH C. Removing bicarbonate from the blood would not affect the pH

B

. In the crystal matrix of ordinary salt, the sodium and chlorine are held together by: A. peptide bonds. B. covalent bonds. C. ionic bonds. D. hydrogen bonds. E. nonpolar bonds.

c

. Two carbon atoms joined to each other by the sharing of two pairs of electrons, form a(n): A. single bond. B. ionic bond. C. double covalent bond. D. hydrogen bond.

c

Oxygen has an atomic mass of 16 and an atomic number of 8. How many neutrons are present? A. 4 B. 24 C. 8 D. 16

c

Plants transport water to their leaves through the xylem when water evaporates from the leaves. The evaporating water pulls other water molecules up the xylem through ____ . A. Covalent bonds B. Ionic bonds C. Hydrogen bonds D. Hydrophobic interactions

c

The atomic number of an element is equal to the number of: A. neutrons only. B. protons plus electrons. C. protons only. D. neutrons plus electrons. E. protons plus neutrons.

c

Which atomic particle has no charge and is located in the nucleus? A. isotope B. proton C. neutron D. electron E. ion

c

Which element's isotope is commonly used to determine when biological samples such as fossils, were formed? A. oxygen B. hydrogen C. carbon D. nitrogen E. sulfur

c

Life is thought to have evolved from complex molecules formed by the interaction of smaller molecules in oceans and the atmosphere. The substance which brought these molecules together to interact is A. hydrogen. B. acids. C. salts. D. buffers. E. water.

E

The two nitrogen atoms in nitrogen gas (N2) share six electrons forming a _____. A. double bond B. hydrogen bond C. single covalent bond D. double covalent bond E. triple covalent bond

E

When water ionizes, it produces equal amounts of hydrogen and hydroxide ions that can reassociate with each other. The pH of water is: A. 3 B. 4 C. 5 D. 6 E. 7

E

Atoms containing a specific number of protons are called: A. elements B. minerals C. molecules D. metals

A

In a chemical analysis of an animal tissue sample, which element would be in the least quantity? A. iodine B. oxygen C. nitrogen D. carbon E. hydrogen

A

In the Hershey-Chase experiment, bacterial viruses, called phage, were used to demonstrate that DNA is the genetic material. The phage that were used for this experiment consisted of DNA surrounded by a protein coat. Phage will attach to specific types of bacteria and inject their DNA into the bacterial cell. To scientifically determine whether DNA is the genetic material, Hershey and Chase made phage in a medium containing radioactive sulfur-35 (S35). Why was S35 used in this experiment? A. Only amino acids contain sulfur. B. Only nucleic acids contain sulfur. C. Both nucleic acids and amino acids contain sulfur. D. The radioactive sulfur labels peptide bonds.

A

Negatively charged subatomic particles that have almost no mass are called: A. electrons. B. protons. C. neutrons. D. ions. E. polymers.

A

Salt is often used to melt ice on roads during the winter because it lowers the freezing/melting point of water. When salt dissolves in water, individual Na+ and Cl- ions break away from the salt lattice and become surrounded by water molecules. Why would this cause ice to melt? A. Hydrogen bonds are broken, and the salt ions interfere with interactions between H and O. As a result, it is more difficult for water molecules to bond and form ice. B. Hydrogen bonds are formed, and the salt ions bond with O. As a result, it is more difficulty for water molecules to bond and form ice. C. Hydrogen bonds are broken, and the salt ions bond with O and H respectively. As a result, it is more difficult for water molecules to bond and form ice.

A

Sue was monitoring the oil spill into the Gulf of Mexico from an oil tanker. From her observations, she noted that the oil was moving as large patches in the water. It did not appear as though the oil was dissolving into the water. Why did the oil not dissolve into the water? A. Hydrophobic interactions B. Surface tension C. Sea water acts as a solvent D. Water forms hydration shells E. Water has a high heat of vaporization

A

The electronegativity of nitrogen (N) is 3.0, while the electronegativity of hydrogen (H) is 2.1. Knowing this, consider how the electrons will be shared in ammonia (NH3). What do you predict about the polarity of ammonia? A. Each H atom has a partial positive charge B. The N atom has a partial positive charge C. Each H atom has a partial negative charge D. The N atom has a strong positive charge

A

The half-life of Carbon-14 is approximately 5,700 years. Using this information scientists have been able to determine the age of some artifacts left by humans. A scientist wants to know approximately how old a piece of wood was that she found on the floor in an old cave that had recently been discovered. She removed the wood (with permission) to her laboratory. Her wood sample contained 2 grams of Carbon-14. If the age of the wood was determined to be 22,800 years old, how much Carbon-14 originally existed in this piece of wood? A. 32 grams B. 16 grams C. 12 grams D. 8 grams E. 4 grams

A

The negative logarithm of the hydrogen ion concentration in the solution is referred to as: A. pH B. atomic mass C. -OH concentration D. electronegativty E. specific heat

A

The reaction (H2 + F2 ® 2HF) is an example of a redox reaction. In reality, two half reactions are occurring. The half reaction (H2 ® 2H+ + 2e-) is a(n): A. oxidation reaction B. redox reaction C. potential energy reaction D. reduction reaction

A

The smallest sub-atomic particle is the ______. A. electron B. neutron C. proton D. ion E. isotope

A

The sub-atomic particle with a positive charge is _____. A. a proton B. an ion C. a neutron D. an isotope E. an electron

A

Water is most dense and thus heaviest at 4oC. At 0oC, ice forms and can float on liquid water. Suppose ice were most dense at 0oC. What would happen in a lake? A. The ice would cover the bottom of the aquatic system and would build up in layers over time. B. The cold temperatures and the subsequent ice formation would prevent hydrogen bonds from forming between the water molecules, thus causing the existing ice crystals to become disassociated from each other. C. The ice would cover the surface of the aquatic system and would never melt. D. Ice would not form because solids are always less dense than liquids.

A

The common basilisk lizard will run across water on its hind legs in an erect position when startled by predators. This lizard has large feet and flaps of skin along its toes. What properties of water allow this lizard to walk on water? A. Hydrogen bonds absorb heat when they break and release heat when they form. This helps to minimize temperature changes. B. The surface tension created by hydrogen bonds is greater than the weight of the lizard initially. C. Polar molecules are attracted to ions and polar compounds, making these compounds soluble. D. Hydrogen bonds hold water molecules together; many hydrogen bonds must be broken for water to evaporate.

B

The number of protons in a given atom is equal to its: A. neutron number B. atomic number C. molecular number D. mass

B

The pH of your small intestines is around 7.5 and the pH of your large intestine can be 5.5. As substances travel from the small intestines to the large intestine, what would happen to the H+ ion concentration? A. It decreases 100 fold. B. It increases by 100 fold. C. It increases 10 fold. D. It increases 2 fold. E. It decreases 10 fold.

B

When atoms gain or lose electrons, they become negatively or positively charged. These negatively or positively charged atoms are known as A. unstable atoms. B. ions. C. isotopes. D. isomers.

B

When two atoms share a pair of electrons, the bonding is referred to as: A. ionic. B. covalent. C. unstable. D. hydrogen.

B

Why is it necessary to take special safety precautions when using radioactivity? A. Radioactive substances will ionize cells. B. Radioactive substances have the potential to cause damage to living cells. C. Radioactive substances decay. D. Radioactive substances will perforate plasma membranes.

B

You identify an enzyme involved in a cellular reaction. How does the enzyme affect the reaction equilibrium between reactants and products and the time needed to reach equilibrium? A. It alters the reaction equilibrium and shortens the time needed to reach equilibrium. B. The reaction equilibrium is unaffected, but it shortens the time needed to reach equilibrium. C. It alters the reaction equilibrium and lengthens the time needed to reach equilibrium. D. The reaction equilibrium is unaffected, but it lengthens the time needed to reach equilibrium.

B

You recently discovered a new element, and find that this particular element one electron its outer energy level. What would you expect will happen to an atom of this element if placed in water? A. It will lose an electron forming a negative ion. B. It will lose an electron forming a positive ion. C. It will gain an electron forming a positive ion. D. It will gain an electron forming a negative ion.

B

An atom has 20 electrons and 20 neutrons. What is the mass of this atom? A. 10 B. 20 C. 40 D. 80

C

Atomic nuclei contain protons and _______. A. moles B. isomers C. neutrons D. ions

C

Capillary action is one of the forces that aids water's upward movement in plants. The narrower the diameter of the tube, the farther the water column will rise. Capillary action is a result of water molecules: A. producing sufficient surface tension to overcome the pull of gravity. B. having a strong cohesive force and attaching to the surrounding vessel walls. C. having an adhesive force, which allows them to attach to the vessel walls. D. storing heat and thus moving faster because of heat of vaporization. E. being associated with hydrophobic molecules, which can result in upward movement.

C

How is the bond in F2 different from the bond in KCl? A. F2 and KCl are both ionic B. F2 is ionic and KCl is covalent C. F2 is covalent and KCl is ionic

C

If a carbon were bonded to two carbons, how many hydrogens could it accept? A. 0 B. 1 C. 2 D. 3 E. 4

C

Isotopes that are unstable and decay when their nucleus breaks up into elements with lower atomic numbers, emitting significant amounts of energy in the process, are called: A. energetic B. ionic C. radioactive D. isometric

C

Matter is composed of: A. molecules B. mass C. atoms D. energy

C

The high heat of vaporization of water helps you to feel cooler when you sweat because the transition of water from a liquid to a gas requires a ______ of energy to break hydrogen bonds. The energy is _____ from heat produced by your body, thus helping to lower the surface temperature of your body. A. release; released B. release; obtained C. input; obtained D. input; released

C

Water molecules are polar with ends that exhibit partial positive and negative charges. These opposite charges allow water molecules to attract each other through: A. ionic bonds. B. covalent bonds. C. hydrogen bonds. D. peptide bonds.

C

. The amino acid glycine (C3NO2H6) is a(an): A. element B. inorganic molecule C. vitamin D. organic molecule

D

A scientist conducts a procedure that causes nitrogen atoms to gain neutrons. The resulting atoms will be: A. ions of nitrogen. B. positively charged. C. negatively charged. D. isotopes of nitrogen. E. new elements with higher atomic numbers

D

After taking your biology exam, you return to your car only to find that you had left the lights on and now the car battery is dead. Your friend offers to jump-start your car, but when you go to hook up the jumper cables you find that the battery terminals are covered with corrosion due to battery acid condensation. Based off your knowledge, what substance could be used to clean the corrosion? A. coffee (pH of 5) B. water (pH of 7) C. vinegar (pH of 3) D. baking soda (pH of 9)

D

How many hydrogen bonds can a water molecule form? A. 1 B. 2 C. 3 D. 4 E. 5

D

Mendeleev found that when he arranged the known elements according to their atomic mass, the entries in the table exhibited a pattern of chemical properties that repeated itself in groups of eight elements. This led to the generalization now known as: A. an atomic model. B. valance electrons. C. the periodic table. D. the octet rule.

D

Regardless of its shape, a given orbital may contain no more than: A. 1 electron. B. 4 electrons. C. 8 electrons. D. 2 electrons.

D

The area around a nucleus where an electron is most likely to be found is the: A. electrical space. B. energy level. C. polar space. D. orbital.

D

Water molecules are attracted to each other due to the opposite charges created by partial charge separations within the molecules. These attractions are called: A. peptide bonds. B. covalent bonds. C. ionic bonds. D. hydrogen bonds. E. double bonds.

D

Because oxygen is more electronegative than hydrogen, the water molecule is: A. hydrophobic. B. hydrophilic. C. nonpolar. D. ionic. E. polar.

E