BIO Test 1

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Water molecules have a polarity, which allows them to be electrically attracted to other water molecules and other polar molecules by weak chemical bonds known as _____. a. hydrogen bonds b. Van der Waals interactions c. ionic bonds d. polar covalent bonds e. nonpolar covalent bonds

What are nonpolar molecules that cluster away from water molecules called? a. Hydrophobic b. Ionic c. Hydrophilic d. None of the listed responses is correct.

What is generally true about essential elements and living organisms? a. Although all forms of life require iron, other elements are required only by certain species. b. Given their low concentrations in nature, the toxicity of some elements is generally not a factor in the evolution of biological communities. c. All organisms require 25 of the 92 naturally occurring elements to survive. d. The elements carbon, hydrogen, nitrogen, and oxygen make up 20-25% of living mass.

What is the appropriate term for an interbreeding group of individuals of a single type occupying a defined area? a. Population b. Species c. Ecosystem d. Community

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

What kind of bond is formed between the two hydrogen atoms and the single oxygen atom? a. polar covalent bonds b. hydrogen bonds c. nonpolar covalent bonds d. ionic bonds

What name is given to the bond between water molecules? a. hydrogen b. hydrophobic c. single (nonpolar) covalent d. polar covalent e. ionic

What results from an unequal sharing of electrons between atoms? a. a polar covalent bond b. a hydrophobic interaction c. radioactive decay d. an ionic bond e. a nonpolar covalent bond

This atom can form up to _____ single covalent bond(s). a. 0 b. 4 c. 3 d. 2 e. 1

Hydrophobic substances such as vegetable oil are _____. A) nonpolar substances that repel water molecules B) nonpolar substances that have an attraction for water molecules C) polar substances that repel water molecules D) polar substances that have an affinity for water

If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, then the concentration of H+ ions _____. A) is 10 times higher in the cytoplasm than in the mitochondrial matrix B) is 10 times higher in the mitochondrial matrix than in the cytoplasm C) in the cytoplasm is 7/8 the concentration in the mitochondrial matrix D) in the cytoplasm is 8/7 the concentration in the mitochondrial matrix

How does 0.5 M sucrose (molecular mass 342) solution compare to 0.5 M glucose (molecular mass 180) solution? a. Sucrose has 171 mg/L, whereas glucose has 90 mg/L. b. Both have 3.01 × 1023 molecules. c. Both have 6.02 × 1023 molecules. d. Sucrose has 171 molecules, whereas glucose has 90.

What results from an unequal sharing of electrons between atoms? A) a nonpolar covalent bond B) a polar covalent bond C) an ionic bond D) a hydrophobic interaction

When a person gets dehydrated while exercising on a hot day, their pituitary gland releases ADH, a hormone that signals the kidneys to retain more water. This is an example of... A) Positive feedback regulation B) Negative feedback regulation C) Chemical cycling D) Emergent properties

Which type of organisms within the domain Eukarya is composed of organisms that are generally unicellular (single-celled)? a. Animals b. Protists c. Plants d. Fungi

A strong acid like HCl _____. A) dissociates completely in an aqueous solution B) increases the pH when added to an aqueous solution C) reacts with strong bases to create a buffered solution D) is a strong buffer at low pH

Hydrogen bonds are _____________ than ionic bonds because they involve the attraction of ___________ ___________ ____________. a. weaker, partial opposite charges b. stronger, partial opposite charges c. weaker, full opposite charges d. stronger, full opposite charges

You can fill a glass of water to just slightly above the rim without the water spilling over the glass. What property of water best explains this phenomenon? a. Adhesion b. Surface tension c. Its polarity d. None of the listed responses is correct.

A water molecule can bond to up to _____ other water molecules by ____ bonds. a. three ... ionic b. two ... polar covalent c. four ... hydrogen d. two ... hydrogen e. four ... polar covalent

From its atomic number of 15, it is possible to predict that the phosphorus atom has _____. A) 5 neutrons, 5 protons, and 5 electrons B) 15 neutrons and 15 protons C) 8 electrons in its outermost electron shell D) 15 protons and 15 electrons

How many electrons are involved in a double covalent bond? A) one B) two C) three D) four

How would acidification of seawater affect marine organisms? Acidification of seawater would _____. A) increase dissolved carbonate concentrations and promote faster growth of corals and shell- building animals B) decrease dissolved carbonate concentrations and promote faster growth of corals and shell- building animals C) increase dissolved carbonate concentrations and hinder growth of corals and shell-building animals D) decrease dissolved carbonate concentrations and hinder growth of corals and shell-building animals

How would you describe a buffer solution? a. strong acid and its conjugate base b. weak acid and its conjugate base c. strong base and its conjugate acid d. weak base and its conjugate acid

Hydrophobic substances such as vegetable oil are ________. a. attraction for water molecules b. polar substances that have an affinity for water c. polar substances that repel water molecules d. nonpolar substances that repel water molecules

If an atom has a charge of +1, which of the following must be true? A) It has two more protons than neutrons. B) It has the same number of protons as electrons. C) It has one more electron than it does protons. D) It has one more proton than it does electrons

Measurements show that the pHpH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake? a. 4.0M b. 10^4 M c. 10^-10 M d. −10^-4 M

Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers from 92-100. Based on this information, which of the following is also true of molybdenum? a. Molybdenum atoms can have between 50 and 58 protons. b. Isotopes of molybdenum have different numbers of electrons. c. Molybdenum atoms can have between 50 and 58 electrons. d. Molybdenum atoms can have between 50 and 58 neutrons.

One difference between carbon-12 (C) and carbon-14 (C) is that carbon-14 has a. two more protons than carbon-12. b. two more electrons than carbon-12. c. two more electrons and two more neutrons than carbon-12. d. two more neutrons than carbon-12. e. two more protons and two more neutrons than carbon-12.

One idea to mitigate the effects of burning fossil fuels on atmospheric CO2 concentrations is to pipe liquid CO2 into the ocean at depths of 2500 feet or greater. At the high pressures at such depths, CO2 is heavier than water. What potential effects might result from implementing such a scheme? A) increased carbonate concentrations in the deep waters B) increased growth of corals from a change in the carbonate-bicarbonate equilibrium C) no effect because carbon dioxide is not soluble in water D) increased acidity and decreased carbonate concentrations in the deep waters

One mole (mol) of glucose (molecular mass = 180 daltons) is _____. A) 180 × 1023 molecules of glucose B) 1 kilogram of glucose dissolved in 1 liter of solution C) 180 kilograms of glucose D) 180 grams of glucose

Oxygen has an atomic number of 8 and most commonly, a mass number of 16. Thus, what is the atomic mass of an oxygen atom? A) approximately 8 grams B) approximately 8 daltons C) approximately 16 grams D) approximately 16 daltons

Pasteur's results showed that: (a) When growth medium is not contaminated by pre-existing cells, cells still grow there. (b) With enough time, any sterile environment will become contaminated with cells. (c) When growth medium is sterilized by boiling, it remains sterile even if new cells are introduced. (d) When growth medium is not contaminated by pre-existing cells, the growth medium remains sterile.

Prokaryotes are classified as belonging to two different domains. What are the domains? A) Bacteria and Eukarya B) Archaea and Monera C) Bacteria and Protista D) Bacteria and Archaea

Rank, from low to high, the pH of blood, stomach acid, and urine. A) blood, urine, and stomach acid B) stomach acid, blood, and urine C) urine, blood, stomach acid D) stomach acid, urine, blood

Some groups of chemical elements react similarly to one another. For example, the chemistries of sodium and of lithium are similar, as are the chemistries of chlorine and of iodine. These similarities in chemistry result when different elements have similar __________. a. atomic size b. energy per electron c. total numbers of electrons d. numbers of outer-shell electrons

Sulfur is in the same column of the periodic table as oxygen, but has electronegativity similar to carbon. Compared to water molecules, molecules of H2S will _____. A) have greater cohesion to other molecules of H2S B) have a greater tendency to form hydrogen bonds with each other C) have a higher capacity to absorb heat for the same change in temperature D) not form hydrogen bonds with each other

Sweating has a cooling effect because of water's high __________. a. specific heat b. buffering capacity c. surface tension d. heat of vaporization

The amount of heat required to convert 1 g of any substance from the liquid to the gaseous state is defined as __________. a. 1 calorie b. the specific heat of that substance c. surface tension d. the heat of vaporization of that substance

The best experimental design _____. A) includes a large sample size for each condition B) includes a control C) alters only one condition between the controls and the experimental condition D) includes a large sample size and a control, and alters only one condition between the controls and the experimental condition

The compound CaSO4 ionizes into a calcium ion and a sulfate ion (SO4). Calcium has two electrons in its outer shell. Upon ionization, what would you expect the charge on the sulfate ion to be? a. -4 b. +1 c. -1 d. -2

The molar mass of glucose is 180 grams per mole (g/mol). Which of the following procedures should you carry out to make a 1 M solution of glucose? Into 0.8 liter (L) of water, dissolve _____. A) 1 g of glucose and then add more water until the total volume of the solution is 1 L B) 18 g of glucose and then add more water until the total volume of the solution is 1 L C) 180 g of glucose and then add 0.2 L more of water D) 180 g of glucose and then add more water until the total volume of the solution is 1 L

The partial negative charge in a molecule of water occurs because a. the oxygen atom acquires an additional electron. b. the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms. c. the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus. d. the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atoms nucleus than around the hydrogen atoms nucleus. e. one of the hydrogen atoms donates an electron to the oxygen atom.

The tendency of an atom to pull electrons toward itself is referred to as its _____. a. ionic potential b. covalency c.polarity d. electronegativity e.tonicity

The tendency of water molecules to stay close to each other as a result of hydrogen bonding __________. a. provides the surface tension that allows small animals to move across a water surface b. helps to keep water moving through the vessels in a tree trunk c. is called cohesion d. is called cohesion, acts to moderate temperature, provides the surface tension that allows small animals to move across a water surface, and helps to keep water moving through the vessels in a tree trunk

There are __________ naturally occurring elements. a. 4 b. 108 c. 25 d. 92

Which statement helps to explain why ice is less dense than liquid water? (a) Water molecules make hydrogen bonds at definite angles. (b) Cold molecules move less than warm molecules.(c) Hydrogen bonds lengthen in the cold. (d) All of the above. (e) Both (a) and (b).

Which statement is part of the explanation for water's high cohesion? (a) Oxygen has four valence orbitals. (b) Oxygen is much more electronegative than hydrogen. (c) Water can hydrogen-bond with other kinds of molecules. (d) All of the above. (e) Both (a) and (b).

Which statement is true of water's tensile strength? (a) It results from hydrogen bonding. (b) It helps to pull water through plants. (c) It involves both cohesion and adhesion. (e) Both (a) and (b). (d) (a), (b), and (c).

Why isn't this insect drowning? a. The insect is swimming. b. The insect is very light. c. The insect is flying just above the water surface. d. It is difficult to change the temperature of water. e. Surface tension.

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

True or false: Ions may form by transferring an atomic nucleus (with or without electrons) to another molecule. a. T b. F

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

Water molecules can form hydrogen bonds with _____. A) compounds that have polar covalent bonds B) oils C) oxygen gas (O2) molecules D) chloride ions

If the pH of a solution is decreased from 9 to 8, it means that the concentration of _____. A) H+ has decreased to one-tenth (1/10) what it was at pH 9 B) H+ has doubled compared to what it was at pH 9 C) H+ has increased tenfold (10X) compared to what it was at pH 9 D) OH- has increased tenfold (10X) compared to what it was at pH 9

You have two beakers. One contains pure water, the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen. A) Equal amounts of NaCl crystals will dissolve in both water and methanol. B) NaCl crystals will not dissolve in either water or methanol. C) NaCl crystals will dissolve readily in water but will not dissolve in methanol. D) NaCl crystals will dissolve readily in methanol but will not dissolve in water.

Which of the following statements is true about buffer solutions? A) They maintain a constant pH when bases are added to them but not when acids are added to them. B) They maintain a constant pH when acids are added to them but not when bases are added to them. C) They fluctuate in pH when either acids or bases are added to them. D) They maintain a relatively constant pH when either acids or bases are added to them.

A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance? A) It is a strong acid that dissociates completely in water. B) It is a strong base that dissociates completely in water. C) It is a weak acid. D) It is a weak base.

A covalent bond is likely to be polar when _____. A) one of the atoms sharing electrons is more electronegative than the other atom B) the two atoms sharing electrons are equally electronegative C) carbon is one of the two atoms sharing electrons D) the two atoms sharing electrons are the same elements

A covalent chemical bond is one in which a. outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms. b. outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom. c. an electron occupies a hybrid orbital located between the nuclei of two atoms. d. protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms. e. electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged.

A glass of grapefruit juice, at pH 3, contains __________ H+ as a glass of tomato juice, at pH 4. a. ten times as much b. twice as much c. half as much d. one-tenth as much

A hydrogen bond __________. a. is a weak chemical bond b. is one in which hydrogen is strongly attracted to a positively charged atom c. is one in which two hydrogen atoms bond to each other d. is a function of hydrophobic interactions

A solution at pH 6 contains __________ than the same amount of solution at pH 8. a. 100 times more H+ b. 4 times more H+ c. 2 times more H+ d. 4 times less H+

A team of scientists has devised a new chemical fertilizer that its members believe will increase crop yields. The team planted three garden plots with corn. The soil was similar in each, and equal amounts of water were applied to each plot. One plot was treated with a common commercial fertilizer, another was treated with the new fertilizer, and the third plot was not given any fertilizer. The experimenters measured yields as bushels of corn from each plot. The plot that did not receive fertilizer was the __________. a. control plot b. experimental plot c. dependent variable d. controlled variable

A(n) _____ refers to two or more atoms held together by covalent bonds. a. molecule b. shell c. community d. isotope e. ion

Adding a base tends to __________ of a solution. a. lower the hydrogen ion concentration and increase the pH b. increase the hydrogen ion concentration and increase the pH c. lower the hydrogen ion concentration and lower the pH d. increase the hydrogen ion concentration and lower the pH

Adhesion is best described as which of the following? a. The clinging of one substance to another substance b. The process by which a crystalline lattice forms c. A property of water that helps moderate Earth's temperature d. The process that contributes to the transport of water and dissolved nutrients in plants by causing water molecules to tug on other water molecules

An atom has four electrons in its valence shell. What types of covalent bonds is it capable of forming? A) single, double, or triple B) single and double only C) single bonds only D) double bonds only

An atom that normally has __________ in its outer shell would not tend to form chemical bonds with other atoms. a. eight electrons b. three electrons c. four electrons d. one electron

An uncharged atom of nitrogen (atomic number = 7) has __________. a. seven protons and seven electrons b. seven neutrons and seven electrons c. seven protons and seven neutrons d. seven neutrons and six protons

As the [H3O+] of the solution decreases, the [OH-] ________. a. decreases and thus the pH increases b. increases and thus pH decreases c. decreases and thus the pH decreases d. increases and thus pH increases

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

Atoms have no electric charge because they have ________. a. an equal number of protons and electrons b. an equal number of protons and neutrons c. uncharged neutrons in their nuclei b. an equal number of charged and uncharged subatomic particles

Atoms with the same number of protons but with different electrical charges _____. a. are different ions b. have different atomic numbers c. are different isotopes d. have different numbers of neutrons e. have different atomic masses

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. Yes. O attracts electrons more strongly than C. d. Right! O is electronegative, so O2 is polar. e. No way. C is more electronegative than O.

Each water molecule is joined to _____ other water molecules by ____ bonds. a. four ... hydrogen b. three ... ionic c. four ... polar covalent d. two ... polar covalent e. two ... hydrogen

Elements found on the left side of the periodic table contain outer shells that are _____; these elements tend to form _____ in solution. A) almost empty; cations B) almost empty; anions C) almost full; cations D) almost full; anions

Emergent properties of living systems are properties that __________. a. are due to the arrangement and interactions of parts as complexity increases b. are apparent only when an organism is studied at the molecular level c. define the cell's surroundings d. are evident during only one portion of the life cycle of an organism

Eukaryotic organisms that decompose dead organisms and absorb the nutrients are generally found in which kingdom? a. Fungi b. Plantae c. Archaea d. Bacteria

Experimentation is only one part of the process of scientific inquiry, but it is a very important step because it __________. a. allows rejection of hypotheses b. ensures that the variable being tested is measured without error c. ensures that hypotheses can be confirmed with certainty d. allows scientists to control all aspects of the system

Fluorine has an atomic number of 9. Which of the following would you do to a neutral fluorine atom to complete its valence shell? A) add 1 electron B) add 2 electrons C) remove 1 electron D) Nothing. If fluorine is neutral, it has a complete valance shell.

How is a covalent bond formed? a. two atoms share two electrons b. one atom loses a pair of electrons to the other c. two atoms share one electron d. two atoms share two pairs of electrons

How would you respond to this reasoning? Oxygen is not a greenhouse gas; therefore, gases containing oxygen—such as ozone, nitrous oxide, and carbon dioxide—are not greenhouse gases either. a. False. Compounds can have emergent properties that are very different from those of the elements that form them. b. True. It is impossible for a gas containing oxygen to be a greenhouse gas. c. True. Compounds display emergent properties that are very similar to those of the elements that form them. d. True. Because oxygen is not a greenhouse gas, it is unlikely to combine with anything at a higher level of organization to form a greenhouse gas.

Dissolving is best described as ... a. a separation of molecules into neutral atoms. b. a mingling of molecules and/or ions. c. a change from a solid to a liquid. d. molecules breaking into ions.~breaking covalent bonds.

If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, then theconcentration of H+ ions _____. A) is 10 times higher in the cytoplasm than in the mitochondrial matrix B) is 10 times higher in the mitochondrial matrix than in the cytoplasm C) in the cytoplasm is 7/8 the concentration in the mitochondrial matrix D) in the cytoplasm is 8/7 the concentration in the mitochondrial matrix

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

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by a. polar covalent bonds. b. van der Waals interactions. c. hydrogen bonds. d. nonpolar covalent bonds. e. ionic bonds.

In this molecule, what type of bond is found between the oxygen and hydrogens? a. polar covalent b. hydrophilic c. ionic d. nonpolar covalent d. hydrophobic

Ionic bonds form as a result of __________. a. attraction between ions that have opposite charges b. sharing of electron pairs between atoms c. unequal sharing of electrons between atoms d. attraction between a hydrogen and other atoms that share electrons unequally

Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers from 92-100. Therefore, which of the following can be true? A) Molybdenum atoms can have between 50 and 58 neutrons. B) Molybdenum atoms can have between 50 and 58 protons. C) Molybdenum atoms can have between 50 and 58 electrons. D) Isotopes of molybdenum have different numbers of electrons.

Nitrogen (N) is more electronegative than hydrogen (H). Which of the following is a correct statement about the atoms in ammonia (NH3)? A) Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge. B) Ammonia has an overall positive charge. C) Ammonia has an overall negative charge. D) The nitrogen atom has a partial positive charge; each hydrogen atom has a partial negative charge.

Nitrogen (N) normally forms three covalent bonds with a valence of 5. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of 1). What do you predict to be the charge on ammonium? A) +1 B) -1 C) +2 D) -2

One mole (mol) of glucose (molecular mass = 180 daltons) is ________. a. 180 grams of glucose b. 1 kilogram of glucose dissolved in 1 liter of solution c. 180 × 1023 molecules of glucose d. 180 mL of dissolved glucose

One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+), as noted below. If the pH of blood increases, one would expect _____. A) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3- B) an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3- C) a decrease in the concentration of HCO3- and an increase in the concentration of H+ D) an increase in the concentration of HCO3- and a decrease in the concentration of OH-

Part completeCould both the food competition hypothesis and the sexual competition hypothesis explain why giraffes have long necks? Why or why not? (a) Yes. Long necks could be advantageous for more than one reason. (b) Yes. All giraffes have been shown to feed at the highest possible height and fight for mates. (c) No. Observations have shown that the food competition hypothesis cannot be correct. (d) No. In science, only one hypothesis can be correct.

Sulfur is in the same column of the periodic table as oxygen but it is less electronegative than oxygen. Compared to water molecules, how will the H2S molecules behave? a. not be able to form hydrogen bonds with each other b. have a higher capacity to absorb heat for the same change in temperature c. have a greater tendency to form hydrogen bonds with each other d. have greater cohesion to other H2S molecules

The absorption of human-generated CO2 by the oceans __________. a. increases the hydrogen ion concentration in the oceans but decreases the carbonate ion concentration and threatens the livability of the oceans for organisms that produce calcium carbonate shells b. increases the oceanic concentration of carbonic acid c. reduces the carbonate ion concentration in the oceans and threatens calcifying organisms in marine ecosystems d. increases the oceans' acidity and pH

The amount of energy that must be absorbed or lost to raise or lower the temperature of 1gram of liquid water by 1°C __________. a. is 1 calorie b. is 1,000 joules c. is 1 kilocalorie d. is 1,000 calories

The application of scientific knowledge for some specific purpose is known as _____. A) technology B) deductive science C) inductive science D) pure scienc

The best method for determining whether bean plants require sodium is to __________. a. grow bean plants with and without sodium b. measure the amount of sodium in a few bean plants c. measure how fast radioactive sodium enters the plant d. look for sodium in leaf tissues using autoradiography

The chemical characteristics or reactivity of an element depend mostly on the __________. a. number of electrons in its outermost shell b. number of electron shells present in the atoms c. mean energy level of its electrons d. degree to which it has more or fewer electrons than protons

The energy used by most organisms for metabolism and growth ultimately comes from __________. a. the sun b. heat c. decomposition of plants and other organic debris d. carbon dioxide

The open spaces in water's crystal structure make it possible for ... (a) aquatic life to exist at the North Pole. (b) water to have a low boiling point. (c) life to occur in hot springs. (d) Both (b) and (c). (e) (a), (b), and (c).

The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called? a. a hydrogen bond b. a covalent bond c. an ionic bond d. a van der Waals interaction e. a hydrophilic bond

The tendency of an atom to pull electrons toward itself is referred to as its _____. a. electronegativity b. covalency c. polarity d. tonicity e. ionic potential

When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)? a. 1 liter of 1.0 M NaCl b. 1 liter of 0.5 M NaCl c. 1 liter of 1.0 M glucose d. 1 liter of 1.0 M NaCl and 1 liter of 1.0 M glucose will contain equal numbers of solute particles.

Which answer helps to explain how many hydrogen bonds a water molecule can form? a. Oxygen's valence shell has four orbitals. b. The oxygen atom has six protons. c. Water can ionize, making hydronium and hydroxide ions. d. Oxygen makes two covalent bonds. e. The angle between H-O bonds in water is 180.

Which bond or interaction would be difficult to disrupt when compounds are put into water? A) covalent bonds between carbon atoms B) hydrogen bonds C) ionic bonds 'D) ionic and hydrogen bond

Which of the following best defines 'one kilocalorie'? a. 1,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°C b. 1,000 calories, or the amount of heat required to raise the temperature of 100 g of water by 100°C c. 1,000 calories, or the amount of heat required to raise the temperature of 1 g of water by 1°C e. 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°F

Which of the following can be attributed to water's high specific heat? a. A lake heats up more slowly than the air around it. b. Sugar dissolves in hot tea faster than in iced tea. c. Ice floats on water. d. Oil and water do not mix well.

Which of the following correctly describes a reaction that has reached chemical equilibrium? A) The rate of the forward reaction is equal to the rate of the reverse reaction. B) All of the reactants have been converted to the products of the reaction. C) All of the products have been converted to the reactants of the reaction. D) Both the forward and the reverse reactions have stopped, with no net effect on the concentration of the reactants and the products.

Which of the following correctly describes all chemical equilibrium? A) Forward and reverse reactions continue with no net effect on the concentrations of the reactants and products. B) Concentrations of products are higher than the concentrations of the reactants. C) There are equal concentrations of products and reactants while forward and reverse reactions continue. D) There are equal concentrations of reactants and products, and the reactions have stopped.

Which of the following explains most specifically the attraction of water molecules to one another? a. hydrogen bond b. ionic bond c. hydrophobic interaction d. polar covalent bond e. nonpolar covalent bond

Which of the following helps most to explain why water has a high specific heat? (a) A water molecule can make 4 hydrogen bonds.(b) The water molecule has exceptionally strong covalent bonds. (c) Water temperature is exceptionally sensitive to heat. (d) Both (a) and (b).Both (b) and (c).

Which of the following reasons explains why a steam burn is more severe than a hot water burn? a. Steam contains more energy than water. b. Water evaporates and leaves the surface faster and helps in cooling. c. Burns caused by liquids are always milder. d. Steam can penetrate the skin.

Which of the following solutions would require the addition of the greatest amount of base to bring the solution to neutral pH? A) gastric juice at pH 2 B) vinegar at pH 3 C) black coffee at pH 5 D) household bleach at pH 12

Which of the following statements best describes when properties emerge? a. The whole is greater than the sum of the parts. b. Only life displays emergent properties. c. This is best observed only at the microscopic level of biology or the atomic level of chemistry. d. The sum of the parts is greater than the whole.

Which of these is an example of inductive reasoning? A) Hundreds of individuals of a species have been observed and all are photosynthetic; therefore, the species is photosynthetic. B) These organisms live in sunny regions. Therefore, they are using photosynthesis. C) If protists are all single-celled, then they are incapable of aggregating. D) If two species are members of the same genus, they are more alike than each of them could be to a different genus.

Which of these provides evidence of the common ancestry of all life? A) near universality of the genetic code B) structure of the nucleus C) structure of cilia D) structure of chloroplasts

Which pair of elements is most likely to react if bought together? a. sodium and chlorine b. hydrogen and argon c. hydrogen and lithium d. nitrogen and oxygen

Which property of water allows a paper towel to pick up a puddle of water? a. adhesion of water molecules to other kinds of molecules b. water's high heat of vaporization c. water's high surface tension

Which property of water allows dogs to cool themselves by panting? a. water's high heat of vaporization b. water's high surface tension c. the formation of covalent bonds between water molecules

Which statement is true about chemical reactions? a. They involve the making and breaking of chemical bonds. b. They represent the way matter is created and destroyed. c. They reach chemical equilibrium when the amounts of products and reactants are equal. d. They may have different numbers of a given atom on each side of the equation arrow.

Which statement must be mentioned in explaining why amphipathic molecules line up at a water surface? a. Polar groups attract one another. b. Polar groups repel water. c. Nonpolar groups repel water. d. Nonpolar groups attract one another. e. All of the above.

Why does ice float in liquid water? a. Stable hydrogen bonds keep water molecules of ice farther apart than water molecules of liquid water. b. The high surface tension of liquid water keeps the ice on top. c. The crystalline lattice of ice causes it to be denser than liquid water. d. The ionic bonds between the molecules in ice prevent the ice from sinking.

Evolution tends to act at which of the following levels? a. Species b. Population c. Domain d. Kingdom

Why is a scientific topic best discussed by people of varying points of view, from different subdisciplines, and representing diverse cultures? A) Robust and critical discussion between diverse groups improves scientific thinking. B) Scientists can coordinate with others to conduct experiments in similar ways. C) This is a way of ensuring that everyone gets the same results. D) People need to exchange their ideas with other disciplines and cultures because everyone has a right to an opinion in science

With evolution as the core theme of biology, we can explain traits shared by organisms as evidence of __________ and traits that differ among organisms as evidence of __________. a. descent from a common ancestor; adaptation through natural selection b. descent from a common ancestor; chance c. coincidence; adaptation d. systems biology; reductionism

You find yourself standing next to a beautiful rose bush. Which of the following do you and the rose have in common? A) You both are multicellular. B) You both lack a membrane-bound nucleus. C) You are both prokaryotic. D) You and the rose have nothing in common.

You need to write down information about a molecule, but need to indicate only the type and number of atoms it contains. Which representation would work best? A) molecular formula B) structural formula C) ball-and-stick model D) space-filling model

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

A controlled experiment _____. A) is repeated many times to ensure that the results are accurate B) includes at least two groups, one of which does not receive the experimental treatment C) includes at least two groups, one differing from the other by two or more variables D) includes one group for which the scientist controls all variables

A covalent bond is likely to be polar if __________. a. the two atoms sharing electrons are of the same element b. one of the atoms sharing electrons is much more electronegative than the other c. the two atoms sharing electrons are equally electronegative d. it is between two atoms that are both very strong electron acceptors

A localized group of organisms that belong to the same species is called a _____. A) community B) population C) ecosystem D) family

A mole of ethyl alcohol weighs 46 g. How many grams of ethyl alcohol are needed to produce 1 L of a 2-millimolar (2 mM) solution? a. 0.92 g b. 0.092 g c. 92 g d. 9.2 g

A neutral atom of chlorine has an atomic number of 17. It has __________ electrons in its third shell. a. 8 b. 7 c. 2 d. 17

A positive ion with two units of charge has 10 neutrons and 8 protons. The ion also has ... a. 12 electrons. b. 6 electrons. c. 10 electrons. d. 8 electrons. e. 16 electrons.

A salamander relies on hydrogen bonding to stick to various surfaces. Therefore, a salamander would have the greatest difficulty clinging to a _____. A) slightly damp surface B) surface of hydrocarbons C) surface of mostly carbon-oxygen bonds D) surface of mostly carbon-nitrogen bonds

A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____. a. compound b. element c. molecule d. proton e. isotope

About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter? a. carbon, oxygen, phosphorus, hydrogen b. carbon, hydrogen, nitrogen, oxygen c. carbon, sodium, hydrogen, nitrogen d. oxygen, hydrogen, calcium, nitrogen e. carbon, oxygen, nitrogen, calcium

Adding acid tends to __________ of a solution. a. increase the hydrogen ion concentration and raise the pH b. increase the hydrogen ion concentration and lower the pH c. decrease the hydrogen ion concentration and raise the pH d. decrease the hydrogen ion concentration and lower the pH

An ionic bond involves _____. a. the unequal sharing of an electron pair b. water avoidance c. no atoms other than sodium and chlorine d. an attraction between ions of opposite charge e. the sharing of a single pair of electrons

At which point in a study is a scientific investigator most likely to use deductive reasoning? a. In rephrasing an alternative hypothesis b. In establishing a test of a hypothesis c. During the formulation of a hypothesis d. During initial observation(s)

Consider the following reaction at equilibrium: What would be the effect of adding additional H2CO3? A) It would drive the equilibrium dynamics to the right. B) It would drive the equilibrium dynamics to the left. C) Nothing would happen, because the reactants and products are in equilibrium. D) The amounts of CO2 and H2O would decrease.

Copper has an atomic number of 29 and a mass number of 64. What would result if an uncharged copper atom lost two electrons? a. The atomic number of the atom would remain 29, the mass number would be reduced to 62, and the atom would be an anion. b. The atomic number would remain 29, the mass number would remain 64, and the atom would be a cation with a +2 charge. c. The atomic number would be reduced to 27, the mass number would remain 64, and the atom would be an anion with a +2 charge. d. The atom would have a double negative charge and be an ion.

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, researchers noticed that males with longer hair get more opportunities to mate and father more offspring. Which of the following research questions would best test the hypothesis that having longer hair is adaptive in these males? a. test whether males with shaved heads are still able to mate b. determine if hair length is heritable c. test whether other traits in these males are also adaptive d. look for evidence of hair in ancestors of tamarins

Despite its cohesion, water can flow because ... a. hydrogen bonds are too weak to affect movements. b. hydrogen bonds break and re-form rapidly. c. many water molecules have no hydrogen bonds. d. hydrogen ions can move between molecules. e. None of the above.

A solution with a pH of 5 has how many more protons in it than a solution with a pH of 7? A) 5 times B) 10 times C) 100 times D) 1000 times

How does a scientific theory differ from a scientific hypothesis? A) Theories are proposed to test scientific hypotheses. B) Theories are usually an explanation for a more general phenomenon; hypotheses typically address more specific issues. C) Hypotheses are usually an explanation for a more general phenomenon; theories typically address more specific issues. D) Confirmed theories become scientific laws; hypotheses become theories.

How is the information encoded in DNA actually used by organisms? a. DNA migrates throughout the cell and interacts directly with other molecules in the cytoplasm. b. The information in DNA is transcribed to RNA and then usually translated into protein. c. DNA is translated into protein and then transcribed to RNA. d. Proteins are built directly from the information in the DNA.

How many electron pairs are shared between carbon atoms in a molecule that has the formula C2H4? A) 1 B) 2 C) 3 D) 4

How many electrons are involved in a single covalent bond? A) one B) two C) three D) four

How many electrons are present in the neutral atom represented in the Periodic Table block in the figure? 18 AR 39.948 a. 19 b. 18 c. 40 d. 22

How many electrons would be present in the valence shell of a sulfur atom (atomic number 16, mass number 32)? a. Two electrons b. Six electrons c. Four electrons d. One electron

How many grams of the compound in the figure above are required to make 1 liter of a 0.5 M solution? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.) A) 29 B) 30 C) 60 D) 150

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

If you were told that concentrations of trace elements above what is required by organisms generally have no effect on those organisms, what would you say? a. True. Only trace element limitation can lead to disease among organisms. b. False. Elevated concentrations of some trace elements such as cobalt and chromium can be toxic. c. False. Increasing the concentration of trace elements above what is required generally has a beneficial effect on organisms. d. True. Most organisms have evolved adaptations that allow them to tolerate very high concentrations of trace elements in the environment.

In a group of water molecules, hydrogen bonds form between which of the following? a. The hydrogen atoms in a single water molecule b. The oxygen atom in one water molecule and a hydrogen atom in another water molecule c. The oxygen atoms in different water molecules d. Two hydrogen atoms in different water molecules right answer feedback:

In an ecosystem, nutrients __________ and energy __________. a. are wasted; is burned b. are recycled; flows through c. flow through; is recycled d. are created; is lost

In living systems molecules involved in hydrogen bonding almost always contain either oxygen or nitrogen or both. How do you explain this phenomenon? A) Oxygen and nitrogen are elements found in both nucleic acids and proteins. B) Oxygen and nitrogen are elements with very high attractions for their electrons. C) Oxygen and nitrogen are elements found in fats and carbohydrates. D) Oxygen and nitrogen were both components of gases that made up the early atmosphere on Earth.

In living systems molecules involved in hydrogen bonding almost always contain either oxygen or nitrogen or both.How do you explain this phenomenon? A) Oxygen and nitrogen are elements found in both nucleic acids and proteins. B) Oxygen and nitrogen are elements with very high attractions for their electrons. C) Oxygen and nitrogen are elements found in fats and carbohydrates. D) Oxygen and nitrogen were both components of gases that made up the early atmosphere on Earth.

In salt, what is the nature of the bond between sodium and chlorine? a. hydrophobic b. ionic c. nonpolar covalent d. polar covalent e. hydrogen

In which of the following will isotopes of an element always differ? a. Number of protons b. Atomic mass c. Atomic number d. Number of electrons

Magnesium has an atomic number of 12. What is the most stable charge for a magnesium ion? A) a +1 charge B) a +2 charge C) a -1 charge D) a -2 charge

Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature? a. the release of heat by the formation of hydrogen bonds b. the absorption of heat by the breaking of hydrogen bonds c. water's high surface tension d. water's ability to dissolve molecules in the air e. water's change in density when it condenses

Many of water's emergent properties, such as its cohesion, its high specific heat, and its high heat of vaporization, result from the fact that water molecules _____. a. are very small b. are attracted to each other by partial negative and positive charges on the oxygen and hydrogen atoms, respectively c. tend to repel each other d. are extremely large e. are in constant motion

Natural selection acts only on traits that are _____. (a) disadvantageous (b) heritable (c) advantageous in a certain environment (d) advantageous

Pharmaceutical researchers are often interested in blocking particular receptor proteins on cell surfaces. What chemical property of a molecule would be most important for this type of application? a. The type of bonding in the molecule b. The molecule's shape c. The number of valence electrons d. The atomic numbers of the atoms involved

Repetition of an experiment _________. a. is too difficult for researchers doing fieldwork b. is necessary before concluding that a given set of results is correct c. should always be done by changing a variable d. is not necessary if the scientist obtains enough background information

Sodas typically contain flavorings, coloring agents, sugar, and carbon dioxide dissolved in water. The best term to describe this mixture would be __________. a. a solute b. an aqueous solution c. an aqueous solvent d. a suspension e. a solvent

Sucrose has a molecular mass of 342 daltons. To make a 2-molar (2 M) solution of sucrose, __________. a. stir 342 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution to 1 L b. stir 342 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 0.5 L c. stir 684 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 0.5 L d. stir 684 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 2 L

The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride? A) MgCl B) MgCl2 C) Mg2Cl D) MgCl3

The atomic number of nitrogen is 7. Nitrogen-15 has a greater mass number than nitrogen-14 because the atomic nucleus of nitrogen-15 contains _____. A) 7 neutrons B) 8 neutrons C) 8 protons D) 15 protons

The cities of Portland, Oregon, and Minneapolis, Minnesota, are at about the same latitude, but Minneapolis has much hotter summers and much colder winters than Portland. Why? A) They are not at the same exact latitude. B) The ocean near Portland moderates the temperature. C) Fresh water is more likely to freeze than salt water. D) Minneapolis is much windier, due to its location in the middle of North America.

The partial charges on a water molecule occur because of __________. a. covalent bonding b. the unequal sharing of electrons between the hydrogen and the oxygen atoms of a water molecule c. widespread ionization d. the achievement of a stable configuration by one atom of a bond but not by the other partner

The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is this attraction called? A) a covalent bond B) a hydrogen bond C) an ionic bond D) a van der Waals interaction

The partial negative charge in a molecule of water occurs because _____. A) the oxygen atom donates an electron to each of the hydrogen atoms B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus C) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms D) one of the hydrogen atoms donates an electron to the oxygen atom

The partial negative charge in a molecule of water occurs because ________. a. the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms b. the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus c. the oxygen atom donates an electron to each of the hydrogen atoms d. one of the hydrogen atoms donates an electron to the oxygen atom

The unequal sharing of electrons within a water molecule makes the water molecule _____. a. hydrophobic b. polar c. have a low surface tension d. ionic e. change easily from a liquid to gaseous form

Though you add heat, the temperature of boiling water remains constant because ... a. it takes energy to break hydrogen bonds. b. it takes energy to break covalent bonds. c. it takes energy to circulate water. d. water has a constant boiling temperature. e. None of the above. f. The temperature rises during boiling.

Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants? A) calcium B) iodine C) sodium D) phosphorus

Water has __________ than other liquids such as ethanol, reflecting its capacity to absorb large amounts of heat. a. lower specific heat b. a higher boiling point c. a lower capacity for forming hydrogen bonds d. a lower heat of vaporization

Water has many exceptional and useful properties. Which is the rarest property among compounds? A) Water is a solvent. B) Solid water is less dense than liquid water. C) Water has a high heat capacity. D) Water has surface tension.

Water has surface tension because ... a. water tends to evaporate from the surface. b. hydrogen bonds between surface water molecules resist being stretched. c. there is positive pressure inside the water mass. d. cohesion forces are weaker at the surface. e. molecules at the surface make more hydrogen bonds.

Water molecules are able to form hydrogen bonds with a. any compound that is not soluble in water. b. compounds that have polar covalent bonds. c. oxygen gas (O2) molecules. d. oils. e. chloride ions.

What do cohesion, surface tension, and adhesion have in common with reference to water? a. All are produced by covalent bonding. b. All are properties related to hydrogen bonding. c. All are results of the structure of the hydrogen atom. d. All have to do with ionic interactions.

What happens when two atoms form a chemical bond? a. Two atoms fuse together to form a chemical bond. b. 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 protons to achieve a stable nucleus.

What is the difference between covalent bonds and ionic bonds? A) Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms. B) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms. C) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between charged atoms. D) Covalent bonds involve the transfer of electrons between charged atoms; ionic bonds involve the sharing of electrons between atoms.

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

What kind of bonds are responsible for the unique cohesion, surface tension, and adhesion properties of water molecules? a. polar covalent bonding b. hydrogen bonding c. ionic bonding d. hydrophobic bonding

A solution with a pH of 5 has how many more protons in it than a solution with a pH of 7? A) 5 times B) 10 times C) 100 times D) 1000 times

When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)? A) 1 liter of 0.5 M NaCl B) 1 liter of 1.0 M NaCl C) 1 liter of 1.0 M glucose D) 1 liter of 1.0 M NaCl and 1 liter of 1.0 M glucose will contain equal numbers of solute particles.

When an ionic compound such as sodium chloride (NaCl) is placed in water, the componentatoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)? A) 1 liter of 0.5 M NaCl B) 1 liter of 1.0 M NaCl C) 1 liter of 1.0 M glucose D) 1 liter of 1.0 M NaCl and 1 liter of 1.0 M glucose will contain equal numbers of solute particles.

When one or more pairs of valence electrons are shared by two neutral atoms, what type of bond is formed? a. A hydrogen bond b. A covalent bond c. An ionic bond d. An electronegative bond

Which answer best describes why does ice float in liquid water? a. The crystalline lattice of ice causes it to be denser than liquid water. b. Stable hydrogen bonds keep water molecules of ice farther apart than water molecules of liquid water. c. The ionic bonds between the molecules in ice prevent the ice from sinking. d. The high surface tension of liquid water keeps the ice on top.

Which branch of biology is concerned with the naming and classifying of organisms? A) informatics B) taxonomy C) genomics D) evolution

Which of the following accurately relates the emergent properties of water to the effects of global warming in the Arctic? a. An increase in water temperature due to global warming will cause the sea ice formed in the Arctic to be denser and less buoyant. b. Ice floats because it is less dense than liquid water; floating ice insulates water below and provides a habitat for some species. The significant increase in Arctic air temperature over the past 50 years is causing a reduction in sea ice, compromising these beneficial effects of sea ice. c. Although a significant increase of air temperature has occurred in the Arctic over the past 50 years, the specific heat of water has thus far buffered against any significant increases in the Arctic ocean temperatures. d. Although it is feared that sea ice around Alaska and northern Canada may be greatly reduced by atmospheric warming, the high specific heat of water has so far buffered these sea ice communities from significant impacts.

Which of the following best describes a model organism? A) It is often pictured in textbooks and easy for students to imagine. B) It is well studied, it is easy to grow, and results are widely applicable. C) It is small, inexpensive to raise, and lives a long time. D) It has been chosen for study by early biologists.

Which of the following can be attributed to water's high specific heat? A) Oil and water do not mix well. B) A lake heats up more slowly than the air around it. C) Ice floats on water. D) Sugar dissolves in hot tea faster than in iced tea.

Which of the following effects can occur because of the high surface tension of water? A) Lakes cannot freeze solid in winter, despite low temperatures. B) A raft spider can walk across the surface of a small pond. C) Organisms can resist temperature changes, although they give off heat due to chemical reactions. D) Sweat can evaporate from the skin, helping to keep people from overheating.

Which of the following has negligible mass? a. Atom b. Electron c. Proton d. Neutron

Which of the following is a trace element? a. Oxygen b. Copper c. Nitrogen d. Hydrogen

Which of the following is an attribute of living things? A. They must be dependent on oxygen. B. They must be capable of acquiring adaptations through evolution. C. They must be able to reproduce sexually. D. They must utilize energy from sunlight, either directly or indirectly.

Which of the following is not an attribute of living things? a. They convert energy from one form to another. b. All living things require oxygen. c. All living things maintain complexity of order. d. Populations of living things evolve.

Which of the following is the best description of a control for an experiment? A) The control group is kept in an unchanging environment. B) The control group is matched with the experimental group except for one experimental variable. C) The control group is exposed to only one variable rather than several. D) Only the experimental group is tested or measured.

Which of the following statements about cells is correct? a. Some cells are non-living in nature. b. Both prokaryotic and eukaryotic organisms are made up of cells. c. Cells are limited in size, which is between 200 to 500 micrometers in diameter. d. Single cells cannot exist independently.

Which of the following statements most clearly demonstrates inductive reasoning? a. If all flying animals are birds, then it can be concluded that bats are birds. b. If the animals observed require organic molecules as nutrients, then it can be concluded that all animals require organic molecules as nutrients. c. A paramecium moves by means of the rhythmic motion of its cilia. d. Because worms lack bones, they are classified as invertebrates.

Which of the following subatomic particles has appreciable mass but no charge? a. Proton b. Neutron c. Electron d. Both proton and neutron

Which of the following takes place as an ice cube cools a drink? A) Molecular collisions in the drink increase. B) Kinetic energy in the liquid water decreases. C) A calorie of heat energy is transferred from the ice to the water of the drink. D) The specific heat of the water in the drink decreases.

Which property of water allows a water strider to walk on water? a. adhesion of water molecules to other kinds of molecules b. water's high surface tension c. the formation of covalent bonds between water molecules

A cell lacking which of the following structures is most likely to be a prokaryote? a. Cell membrane b. Nucleic acid c. Nuclear membrane d. Cytoplasm

A company was testing a new drug it thought would help decrease the risk of transmission of viruses from mother to fetus. In an experiment to test the compound, an investigator gave 400 pregnant female rats a small dose of the experimental drug and inoculated each with a type of virus known to cause disease in rats. At the same time, 400 other pregnant rats were given only the virus. Of the rat pups born to the females that received both the virus and the drug, 197 showed no symptoms of the disease; 205 rat pups born to the virus-only females showed symptoms. From these data, we can best conclude __________. a. nothing because no control group was used in the test of the drug b. that the drug is effective and testing on humans should begin c. that the drug seems to have little effect on viral transmission at the dosage given d. nothing because no independent variable could be identified

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 their respective orbitals D) outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom

A dietary Calorie equals 1 kilocalorie. Which of the following statements correctly defines 1 kilocalorie? One kilocalorie equals _____. A) 1000 calories, or the amount of heat required to raise the temperature of 1 g of water by 1°C B) 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°F C) 1000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°C D) 1000 calories, or the amount of heat required to raise the temperature of 100 g of water by 100°C

A friend of yours calls to say that his car would not start this morning. He asks for your help. You say that you think the battery must be dead. If so, then jump-starting the car from a good battery will solve the problem. In doing so, you are _____. A) testing a theory for why the car will not start B) making observations to inspire a theory for why the car will not start C) stating a hypothesis and using that hypothesis to make a testable prediction D) comparing multiple hypotheses for why the car will not start

A particular carbon isotope has an atomic number of 6 and an atomic mass of 14. The respective numbers of neutrons, protons, and electrons that this carbon isotope has are __________. a. 6, 8, and 6 b. 8, 6, and 8 c. 8, 6, and 6 d. 6, 6, and 8

A phrase that applies to covalent bonding and not other kinds of bonds is ... a. charge attraction. b. paired electrons c. electron-sharing. d. great strength. e. All of the above.

Agrobacterium infects plants and causes them to form tumors. You determine that tumor formation requires a large amount of the plant's energy for tissue formation. How might this change the number of offspring a plant produces, and what is the most likely explanation for this change? A) The number of offspring should increase, because in general, illness increases the reproductive output of organisms. B) The number of offspring should increase, because the bacteria will provide energy for the plant. C) The number of offspring should decrease, because the plant will divert energy from reproduction to tumor formation. D) There should be no effect of infection on offspring production because energy for reproduction is independent of infection.

An element has eight protons, nine neutrons, and eight electrons. Its atomic number and atomic mass, respectively, are __________. a. 9 and 16 b. 8 and 16 c. 8 and 17 d. 9 and 17

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

Based on electron configuration, which of the elements in the figure above would exhibit a chemical behavior most like that of oxygen? A) carbon B) nitrogen C) sulfur D) phosphorus

Bonds between two atoms that are equally electronegative are _____. A) hydrogen bonds B) polar covalent bonds C) nonpolar covalent bonds D) ionic bonds

Carbon-12 is the most common isotope of carbon and has a mass number of 12. However, the average atomic mass of carbon found on a periodic table is slightly more than 12 daltons. Why? A) The atomic mass does not include the mass of electrons. B) Some carbon atoms in nature have an extra proton. C) Some carbon atoms in nature have more neutrons. D) Some carbon atoms in nature have a different valence electron distribution

Cells are _____. (a) only found in pairs, because single cells cannot exist independently (b) limited in size to 200 and 500 micrometers in diameter (c) characteristic of prokaryotic and eukaryotic organisms (d) characteristic of eukaryotic but not prokaryotic organisms

Changing the number of _____ would change an atom into an atom of a different element. a. electrons circling the nucleus of an atom b. bonds formed by an atom c. protons in an atom d. particles in the nucleus of an atom e. neutrons in an atom

Charles Darwin proposed a mechanism for descent with modification that stated that organisms of a particular species are adapted to their environment when they possess _____. A) non-heritable traits that enhance their survival in the local environment B) non-heritable traits that enhance their survival and reproductive success in the local environment C) heritable traits that enhance their survival and reproductive success in the local environment D) heritable traits that decrease their survival and reproductive success in the local environment

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is adaptive in these males, you should _____. A) test whether other traits in these males are also adaptive B) look for evidence of hair in ancestors of tamarins C) determine if hair length is heritable D) test whether males with shaved heads are still able to mate

Darwin's finches, collected from the Galápagos Islands, illustrate which of the following? A) mutation frequency B) ancestors from different regions C) adaptive radiation D) vestigial anatomical structures E) the accuracy of the fossil record

Dr. Haxton told his class that a water molecule can make 4 hydrogen bonds, all of them in the same plane as the three atoms. What would a good student reply? (a) Wrong! Each atom makes one hydrogen bond, for a total of 3. (b) Right! Hydrogen bonds form at both ends of each covalent bond. (c) Wrong! Two hydrogen bonds are not in the plane of the atoms. (d)None of the above. (e) The student would say both (a) and (c).

Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that a. the atom would become a positively charged ion, or cation, and become a radioactive isotope. b. the atom may become a radioactive isotope.the atom would become a negatively charged ion, or anion. c. an electron may move to an electron shell farther away from the nucleus. d. an electron may move to an electron shell closer to the nucleus.

For most atoms, when does the configuration of electrons make the atom unreactive? a. When the atom achieves a zero net charge b. When the atom has as many protons as neutrons c. When the atom has eight electrons in its outermost shell d. When the atom has moved all its electrons to its outermost shell

How does the polarity of water contribute to its ability to dissolve so many substances? a. Because it is polar, water forms ionic bonds with the ions in substances such as NaCl (salt). b. Natural water has a pH of approximately 5.6, which is slightly acidic. Acids can dissolve more substances than bases can. c. Because it is polar, water's negatively charged oxygen atoms and positively charged hydrogen atoms are attracted to positively and negatively charged ions and molecules. d. Water's polarity allows it to form covalent bonds with many substances.

Hydrogen Bonds are ____________ than covalent bonds because they do not involve sharing of ____________. a. stronger; protons b. stronger; electrons c. weaker; electrons d. stronger; protons

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

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

If water were not a polar molecule, how would the effects of climatic warming differ from those currently observed or predicted to occur in the future? a. If water molecules were nonpolar, then water vapor would be less effective as a greenhouse gas, and the effects of global warming would be less extreme. b. If water were nonpolar, the effects on global warming would be only slightly worse because there are other polar molecules that can moderate climate as water does. c. The effects would be drastically worse because the loss of the polar nature of water would greatly reduce its specific heat and its ability to moderate temperature. d. The effects would be worse because a loss of the polar molecular structure would lead to a greater amount of heat absorbed by water molecules and, thus, an increase in its specific heat.

If you change the number of neutrons in an atom, you create _____. A) a cation B) an anion C) an isotope D) a different element

Imagine that organisms consisted of 70-95% alcohol instead of 70-95% water. Alcohol's specific heat is about half that of water. How would living things be different? a. Living organisms would have to be much smaller. b. Warm-blooded organisms would require less insulation such as fur or feathers. c. Systems for temperature regulation would have to be much more efficient. d. Organisms would be able to live in a much wider range of temperatures.

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

In comparison to eukaryotes, prokaryotes _____. A) are more structurally complex B) are larger C) are smaller D) do not have membranes

In presenting data that result from an experiment, a group of students show that most of their measurements fall on a straight diagonal line on their graph. However, two of their data points are "outliers" and fall far to one side of the expected relationship. What should they do? A) Do not show these points because clearly something went wrong in the experiment. B) Average several trials, rule out the improbable results, and do not show them in the final work. C) Show all results obtained and then try to explore the reason(s) for these outliers. D) Change the details of the experiment until they can obtain the expected results.

In the process of science, which of these is tested? A) a result B) an observation C) a hypothesis D) a control group

In what way are elements in the same column of the periodic table the same? They have the same number of _____. A) protons B) electrons when neutral C) electrons in their valence shells when neutral D) electron shells when neutral

Increased atmospheric CO2 concentrations might have what effect on seawater? A) Seawater will become more alkaline, and carbonate concentrations will decrease. B) There will be no change in the pH of seawater, because carbonate will turn to bicarbonate. C) Seawater will become more acidic, and carbonate concentrations will decrease. D) Seawater will become more acidic, and carbonate concentrations will increase.

Knowing the atomic mass of an element allows inferences about which of the following? A) the number of electrons in the element B) the number of protons in the element C) the number of protons plus neutrons in the element D) the number of protons plus electrons in the element

Melting of ice and thus reduced feeding opportunities for polar bears is occurring because of the ________. a. constant breaking and reforming of hydrogen bonds in water b. drying up of lakes and streams c. increase in CO2 and other greenhouse gases in the atmosphere d. increase in phytoplankton population

Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)? a. The nitrogen atom has a full positive charge; each hydrogen atom has a full positive charge. b. There are covalent bonds between the hydrogen atoms and polar bonds between each hydrogen atom and the nitrogen atom. c. Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge. d. The nitrogen atom has a partial positive charge; each hydrogen atom has a partial negative charge. e. Each hydrogen atom has a partial negative charge; the nitrogen atom has a full positive charge.

One liter of a solution of pH 2 has how many more hydrogen ions (H+) than 1 liter of a solution of pH 6? A) 4 times more B) 40,000 times more C) 10,000 times more D) 100,000 times more

One mole of the compound above would weigh how many grams? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.) A) 29 B) 30 C) 60 D) 150

One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+), as noted above. If the pH of 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 bicarbonate ions (HCO3-) to increase C) the HCO3- to act as a base and remove excess H+ by the formation of H2CO3 D) the HCO3- to act as an acid and remove excess H+ by the formation of H2CO3

Phosphorus-32 (radioactive) has __________ than phosphorus-35 (normal). a. three more neutrons b. three fewer protons c. three fewer neutrons d. three more protons

Radon is a radioactive gas that seeps into homes from the soil. It is thought to be a cause of lung cancer. A research team investigates this hypothesis. The members of the team gather large amounts of data on basement radon concentrations and lung cancer rates and conclude that the more radon there is in a home, the more likely are people living in the home to develop lung cancer. After the study is published, other researchers criticize it by asserting that the studied neighborhoods with higher radon concentrations also have a higher percentage of older people and a higher percentage of cigarette smokers than the low-radon neighborhoods. Both advanced age and cigarette smoking increase the risk of lung cancer. This criticism, if correct, shows that the radon study suffered from __________. a. a lack of replication b. an untestable hypothesis c. uncontrolled variables d. nonsystematic observation and analysis of data

Should an experiment test only one variable at a time? Why or why not? a. No, it is not necessary to test only one variable per experiment, especially when time is of the essence. b. As long as the experiment is repeated a sufficient number of times, it does not matter how many variables are used. c. Yes, an experiment should test only one variable at a time. This ensures that the experimental outcome is clearly due to one identifiable factor. d. Yes, an experiment should test only one variable at a time. That way, the experiment will have to be performed only once.

The ability of water molecules to form hydrogen bonds with other water molecules and water's ability to dissolve substances that have charges or partial charges are __________. a. both caused by water's ability to form covalent bonds with hydrophobic substances b. due to water's partial charges and low molecular mass, respectively c. both caused by water's partial charges d. both caused by water's two electron shells right answer feedback:

The amount of heat required to change the temperature of 1 g of any substance by 1°C is defined as __________. a. 1 kilocalorie b. the heat of vaporization of that substance c. the specific heat of that substance d. 1 calorie

The loss of water from a plant by transpiration cools the leaf. Movement of water in transpiration requires both adhesion to the conducting walls and wood fibers of the plant and cohesion of the molecules to each other. A scientist wanted to increase the rate of transpiration of a crop species to extend its range into warmer climates. The scientist substituted a nonpolar solution with an atomic mass similar to that of water for hydrating the plants. What do you expect the scientist's data will indicate from this experiment? A) The rate of transpiration will be the same for both water and the nonpolar substance. B) The rate of transpiration will be slightly lower with the nonpolar substance as the plant will not have evolved with the nonpolar compound. C) Transpiration rates will fall to zero as nonpolar compounds do not have the properties necessary for adhesion and cohesion. D) Transpiration rates will increase as nonpolar compounds undergo adhesion and cohesion with wood fibers more readily than water.

The most common form of calcium has 20 protons, 20 neutrons, and 20 electrons. Which of the following elements would be an isotope of calcium? a. An atom with 21 protons, 21 neutrons, and 21 electrons b. An atom with 20 protons, 20 neutrons, and 18 electrons c. An atom with 20 protons, 21 neutrons, and 20 electrons d. An atom with 21 protons, 20 neutrons, and 21 electrons

The number of protons in an uncharged atom __________. a. equals the number of neutrons b. varies from isotope to isotope c. equals the number of electrons d. equals the number of electrons in the outer orbital of the atom

The partial negative charge in a molecule of water occurs because ________. a. one of the hydrogen atoms donates an electron to the oxygen atom b. the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms c. the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus d. the oxygen atom donates an electron to each of the hydrogen atoms

The phenomenon responsible for maintaining the upward movement of water through vessels in a tree is __________. a. surface tension b. hydration shells c. cohesion d. specific heat

The reason that coastal climates are more moderate than inland climates primarily water's high __________. a. heat of vaporization b. adhesion c. specific heat d. surface tension

The tendency of an atom to pull electrons toward itself is referred to as its _____. a. tonicity b. covalency c. electronegativity d. ionic potential e. polarity

The unequal sharing of electrons within a water molecule makes the water molecule _____. a. change easily from a liquid to gaseous form b. have a low surface tension c. polar d. hydrophobic e. ionic

The unequal sharing of electrons within a water molecule makes the water molecule _____. a. have a low surface tension b. change easily from a liquid to gaseous form c. ionic c. polar d. hydrophobic

To understand the chemical basis of inheritance, we must understand the molecular structure of DNA. This is an example of the application of which concept to the study of biology? A) evolution B) emergent properties C) reductionism D) feedback regulation

Van der Waals interactions result when a. hybrid orbitals overlap. b. two polar covalent bonds react. c. electrons are not symmetrically distributed in a molecule. d. a hydrogen atom loses an electron. e. molecules held by ionic bonds react with water.

Water molecules are attracted to one another by _____. A) nonpolar covalent bonds B) ionic bonds C) hydrogen bonds D) hydrophobic interactions

What are the four most abundant elements found in living systems? (Concept 2.1) SHOW HINT a. Hydrogen, oxygen, calcium, and nitrogen b. Nitrogen, carbon, sulfur, and oxygen c. Hydrogen, oxygen, nitrogen, and carbon d. Hydrogen, oxygen, nitrogen, and carbon dioxide

What is the atomic number of the neutral atom represented by the Periodic Table block in the figure? 18 AR 39.948 a. 22 b. 19 c. 18 d. 39

What is the difference between covalent bonds and ionic bonds? a. Covalent bonds are formed between atoms to form molecules; ionic bonds are formed between atoms to form compounds. b. Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms. c. Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms. d. Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between atoms. e. Covalent bonds involve the transfer of electrons between atoms; ionic bonds involve the sharing of electrons between atoms.

What is the hydrogen ion (H+) concentration of a solution of pH 8? A) 8 M B) 8 x 10-6 M C) 10-8 M D) 10-6 M

What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms? A) 2 B) 4 C) 6 D) 8

What is the pattern component of the theory of chemical evolution? (a) Most chemical evolution occurred at black smokers. (b) Heat and electrical discharges were required for chemical evolution to occur. (c) Increasingly complex carbon-containing molecules formed early in Earth history. (d) The process occurred at black smokers, in the atmosphere and oceans, or in outer space.

What is the role of van der Waals interactions in biological molecules? a. Van der Waals interactions are strong bonds that play a major structural role in holding proteins together. b. Van der Waals interactions are too weak to be significant. c. Although they are weak bonds, van der Waals interactions help to reinforce the three-dimensional shapes of large molecules. d. Van der Waals interactions are important only in water.

What kind of bond is formed between the two hydrogen atoms and the single oxygen atom? a. hydrogen bonds b. nonpolar covalent bonds c. polar covalent bonds d. ionic bonds

What kind of bonds are responsible for the unique cohesion, surface tension, and adhesion properties of water molecules? a. ionic bonding b. polar covalent bonding c. hydrogen bonding d. hydrophobic bonding

When are atoms most stable? A) when they have the fewest possible valence electrons B) when they have the maximum number of unpaired electrons C) when all of the electron orbitals in the valence shell are filled D) when all electrons are paired

When do hydrogen bonds occur? a. When a molecule with partial charges contacts a molecule without partial charges b. When two atoms achieve stable electron configurations by sharing electrons with each other c. When partial opposite charges on molecules come close enough to attract each other d. When a molecule with a low molecular weight is bonded to a molecule with a high molecular weight

When the atoms involved in a covalent bond have the same electronegativity, what type of bond results? A) an ionic bond B) a hydrogen bond C) a nonpolar covalent bond D) a polar covalent bond

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

Which bond or interaction would be difficult to disrupt when compounds are put into water? a. hydrogen bond b. van der Waals interaction c. covalent bond d. ionic bond e. either covalent bond or ionic bond

Which of the following are qualities of any good scientific hypothesis? I. It is testable. II. It is falsifiable. III. It produces quantitative data. IV. It produces results that can be replicated. A) I only B) III only C) I and II D) III and IV

Which of the following best describes what occurred after the publication of Charles Darwin's On the Origin of Species? A) The publisher was pressured to cease distribution. B) The book was banned from schools. C) The book was widely discussed and disseminated. D) The book was discredited by most scientists.

Which of the following domains is prokaryotic? a. Protists b. Fungi c. Archaea d. Eukarya

Which of the following is a property of liquid water? Liquid water _____. A) is less dense than ice B) has a specific heat that is lower than that for most other substances C) has a heat of vaporization that is higher than that for most other substances D) is nonpolar

Which of the following is the best description of an atom's physical structure? A) An atom is a solid mass of material. B) The particles that form an atom are equidistant from each other. C) Atoms are little bubbles of space with mass concentrated at the center of the bubble. D) Atoms are little bubbles of space with mass concentrated on the outside surface of the bubble.

Which of the following is the fundamental unit of structure and function in living organisms? a. Organelle b. Tissue c. Cell d. organ

Which of the following is true of oxygen that has 8 protons, 8 neutrons, and 8 electrons? a. It has a charge of +8. b. It has a mass number of 8. c. It has an atomic number of 8. d. It has atomic number of 16.

Which of the following occurs because molecules of water are farther apart in ice than in liquid water? a. Ice expands when it melts. b. Ice vaporizes before liquid water does. c. Ice floats. d. Ice is denser than liquid water.

Which of the following statements correctly describes the property of hydrophobic substances such as vegetable oil? a. polar substances that have an affinity for water b. polar substances that repel water molecules c. nonpolar substances that repel water molecules d. nonpolar substances that have an attraction for water molecules

Which of the following statements is FALSE regarding the complexity of biological systems? A) An understanding of the interactions between different components within a living system is a key goal of a systems biology approach to understanding biological complexity. B) Knowing the function of a component of a living system can provide insight into its structure and organization. C) Understanding the chemical structure of DNA reveals how it directs the functioning of a living cell. D) An ecosystem displays complex properties not present in the individual communities within it.

Which of the following statements is FALSE? A) Carbon, hydrogen, oxygen, and nitrogen are the most abundant elements of living matter. B) Some naturally occurring elements are toxic to organisms. C) All life requires the same essential elements. D) Iron is needed by all humans.

Which of the following types of cells use deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope? a. fungi b. animal c. archaean d. plant

Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope? A) animal B) plant C) archaean D) fungi

Which statement describes a reversible reaction that has reached chemical equilibrium? a. The concentration of the reactants is equal to the concentration of the products. b. The rate of the reverse reaction exceeds the rate of the forward reaction. c. The rate of the reverse reaction equals the rate of the forward reaction. d. The forward and the reverse reactions have stopped.

Which type of bond must be broken for water to vaporize? A) ionic bonds B) polar covalent bonds C) hydrogen bonds D) both polar covalent bonds and hydrogen bonds

Why are cell membranes composed primarily of hydrophobic molecules? a. Cell membranes must be hydrophobic in order to allow polar and charged molecules to enter and leave the cell. b. Cell membranes must be composed of polar molecules in order to interact with the aqueous solutions inside cells. c. In order to perform their function of separating the aqueous solutions outside cells from the aqueous solutions inside cells, cell membranes cannot be soluble in water. d. In order to maintain a proper pH, cell membranes must be hydrophobic.

Why are radioactive isotopes useful in scientific research? a. Because they decay spontaneously and give off energy and subatomic particles b. Because they are difficult to detect in small amounts but living cells cannot distinguish them from the corresponding stable isotopes c. Because they can be used as tracers to follow particular atoms and molecules through metabolic pathways d. Because they are not readily incorporated into biological reactions

Why does ice float in liquid water? A) The high surface tension of liquid water keeps the ice on top. B) The ionic bonds between the molecules in ice prevent the ice from sinking. C) Stable hydrogen bonds keep water molecules of ice farther apart than water molecules of liquid water. D) The crystalline lattice of ice causes it to be denser than liquid water

Why doesn't oil mix with water? (a) Nonpolar molecules repel water molecules. (b) Polar molecules repel nonpolar molecules. (c) Polar molecules attract one another. (d) Nonpolar molecules attract one another. (e) Both (a) and (d).

Identify all correct statements about the ionization of water. a Water ionizes to form peroxide and hydronium ions. b. Dissociation of water produces equal masses of OH- and H+. c. Dissociation of water produces equal numbers of OH- and H+. d. Water ionizes to form hydroxide and hydronium ions. e. Dissociation of water is not reversible. f. Dissociation of water is reversible.

c, d, f

1) Cells are _____. A) only found in pairs, because single cells cannot exist independently B) limited in size to 200 and 500 micrometers in diameter C) characteristic of eukaryotic but not prokaryotic organisms D) characteristic of prokaryotic and eukaryotic organisms

A beaker contains 100 milliliters (mL) of NaOH solution at pH = 13. A technician carefully pours into the beaker 10 mL of HCl at pH = 1. Which of the following statements correctly describes the result of this mixing? A) The concentration of Na+ ions will rise. B) The pH of the beaker's contents will increase. C) The pH of the beaker's contents will be neutral. D) The pH of the beaker's contents will decrease.

A covalent bond is likely to be polar when a. the two atoms sharing electrons are equally electronegative.one of the atoms has absorbed more energy than the other atom. b. the two atoms sharing electrons are different elements. c. oxygen is one of the two atoms sharing electrons. d. one of the atoms sharing electrons is much more electronegative than the other atom.

A hypothesis must be testable to be scientifically valid. Being testable for being true or false means that __________. a. only a controlled experiment can prove whether the hypothesis is correct or incorrect b. there must be several options in the hypothesis to choose from, one of which is correct c. the hypothesis has been proved wrong d. some conceivable observation or experiment could reveal whether a given hypothesis is incorrect

A molecule that has all nonpolar covalent bonds would be __________. a. hydrophilic b. acidic c. basic (alkaline) d. hydrophobic

A scientific theory is __________. a. not correct unless it is several years old b. a poorly supported idea that has little backing but might be correct c. the same thing as a hypothesis d. a well-supported concept that has broad explanatory power

A slice of pizza has 500 kcalkcal. If we could burn the pizza and use all the heat to warm a 50-LL 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 kgkg.) a. 50C b. 5C c. 100C d. 10C

A solution contains 0.0000001 (10-7) moles of hydroxyl ions [OH-] per liter. Which of the following best describes this solution? A) acidic: H+ acceptor B) basic: H+ acceptor C) acidic: H+ donor D) neutral

A substance that minimizes changes in the concentration of H+ and OH- in a solution is a __________. a. strong acid b. hydrophobic molecule c. NaCl d. buffer

About twenty-five of the ninety-two natural elements are known to be essential to life. Which four of these twenty-five elements make up approximately 96 percent of living matter? A) carbon, sodium, hydrogen, nitrogen B) carbon, oxygen, phosphorus, hydrogen C) oxygen, hydrogen, calcium, nitrogen D) carbon, hydrogen, nitrogen, oxygen

Agrobacterium infects plants and causes them to form tumors. You are asked to determine how long a plant must be exposed to these bacteria to become infected. Which of the following experiments will provide the best data to address that question? A) Determine the survival rate of Agrobacterium when exposed to different concentrations of an antibiotic. B) Measure the number of tumors formed on a plant when exposed to various concentrations ofAgrobacterium. C) Measure the concentration of Agrobacterium in different soil environments where the plants grow. D) Measure the number of tumors formed on plants, which are exposed to Agrobacterium for different lengths of time.

An acid is __________. a. any compound with a pH b. a material that resists changes in the pH of a solution c. any compound that accepts hydrogen ions d. a compound that donates hydrogen ions to a solution

Because organisms are made primarily of water, they resist rapid temperature changes. This useful quality is based on water's _____. a. cohesion b. buffering activity c. ability to form colloids d. high specific heat e. lower density in the solid phase

Can the atomic mass of an element vary? A) No, it is fixed. If it changes at all then you have formed a different element. B) Yes. Adding or losing electrons will substantially change the atomic mass. C) Yes. Adding or losing protons will change the atomic mass without forming a different element. D) Yes. Adding or losing neutrons will change the atomic mass without forming a different element.

Cells are surrounded by water, with which they are mostly filled. Which of the following occurs as a result? a. The temperature of living things tends to change relatively slowly. b. A variety of nutrient molecules is readily available as dissolved solutes. c. Waste products produced by cell metabolism can be easily removed. d. All of the listed responses are correct. right answer feedback:

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 Y is 1000 times as great as the concentration of hydrogen ions in solution X C) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y D) the concentration of hydrogen ions in solution X is 1000 times as great as the concentration of hydrogen ions in solution Y

To act as an effective coolant in a car's radiator, a substance has to have the capacity to absorb a great deal of heat. You have a reference book with tables listing the physical properties of many liquids. In choosing a coolant for your car, which table would you check first? A) pH B) density at room temperature C) heat of vaporization D) specific heat

Water is a polar molecule. What does this statement mean? a. That water is one of the many hydrophobic molecules b. That the atoms in water have equal electronegativities c. That water molecules are linear, like a pole d. That atoms in the molecule have partial charges as a result of unequal sharing of electrons in a covalent bond

Water is a very versatile solvent because water molecules are __________. a. ionic b. nonpolar c. hydrophobic d. polar

Water molecules have a polarity, which allows them to be electrically attracted to other water molecules and other polar molecules by weak chemical bonds known as _____. a. polar covalent bonds b. Van der Waals interactions c. nonpolar covalent bonds d. hydrogen bonds e. ionic bonds

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their a. volume. b. mass. c. number of atoms. d. number of molecules.

What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms? a. 2 b. 4 c. 3 d. 6 e. 8

What is the molecule that is responsible for both the unity and the diversity of life? a. Protein b. Ribosomes c. Lipids d. DNA

What process exerts the pull on water molecules that is relayed from leaf to root via cohesion? a. antigravity b. precipitation c. gravity d. evaporation

What type of bond is joining the two hydrogen atoms? a. hydrophilic b. ionic c. hydrogen d. covalent e. hydrophobic

When the proton number and electron number are unequal, the atom or molecule __________. a. gains or loses a proton b. becomes part of a molecule c. forms a covalent bond with another atom d. is an ion

When two atoms are equally electronegative, they will interact to form a. polar covalent bonds. b. ionic bonds. c. hydrogen bonds. d. nonpolar covalent bonds. e. van der Waals interactions.

Which action would involve the greatest transfer of heat? a. Cooling 10 g of water from 80°C to 40°C b. Evaporating 1 g of water at 25°C c. Changing the temperature of 1 g of water from 10°C to 90°C d. Condensing 5 g of steam to liquid water

Which branch of biology is concerned with the naming and classifying of organisms? a. genomics b. evolution b. informatics d. taxonomy

Which factor is important in making it possible to cool yourself by sweating? (a) Molecules collide with varied angles and speeds. (b) Hydrogen bonds are relatively weak. (c) Water has more energy at the body surface. (d) Both (a) and (b). (e) (a), (b), and (c).

Which molecule has the shape of a completed tetrahedron? a. Hydrogen gas (H2) b. Water (H2O) c. Oxygen gas (O2) d. Methane (CH4)

Which of the following are compounds? A) H2O, O2, and CH4 B) H2O and O2 C) O2 and CH4 D) H2O and CH4, but not O2

Which of the following best explain why argon, which is a noble gas, does not react with other elements. Noble gases ________. a. have a high positive charge that repels most elements b. have very small atoms c. are not found in abundance on our planet d. have completely paired up and stable electron shells

Which of the following can best be considered a biological system? a. A single liver cell b. the biosphere c. A pond d. All of the listed responses are correct.

Which of the following dissociates completely in solution and is considered to be a strong base (alkali)? A) HCl B) NH3 C) H2CO3 D) NaOH

Which of the following dissociations is that of an acid? a. H2O → H+ + OH- b. NH3 + H+ → NH4+ c. NaOH → Na+ + OH- d. HF → H+ + F-

Which of the following has the smallest total mass? a. 1 neutron plus 1 proton b. 1 electron plus 1 neutron c. two neutrons d. two electrons

Which of the following is (are) true of natural selection? A) It requires genetic variation. B) It results in descent with modification. C) It involves differential reproductive success. D) It requires genetic variation, results in descent with modification, and involves differential reproductive success.

Which of the following is outside the realm of scientific inquiry? a. Explaining naturally occurring events b. Formulating testable hypotheses in seeking natural causes for natural phenomena c. Determining the physical causes for physical phenomena d. Addressing ethical dilemmas

Which of the following observations and inferences led Charles Darwin to his theory of natural selection as a mechanism for evolution? a. Individuals in a population of any species vary in many heritable traits. b. A population of any species has the potential to produce far more offspring than will survive to produce offspring of their own. c. Individuals with heritable traits best suited to the local environment will generally produce a disproportionate number of healthy, fertile offspring. d. Darwin synthesized his theory of natural selection from all of the listed observations and inferences.

Which of the following statements correctly describes the property of hydrophobic substances such as vegetable oil? a. nonpolar substances that have an attraction for water molecules b. polar substances that repel water molecules c. polar substances that have an affinity for water d. nonpolar substances that repel water molecules

Which of the following statements is true for water in its liquid state? a. It has a specific heat lower than most other substances. b. It is nonpolar. c. It is less dense than ice. d. It has a heat of vaporization higher than most other substances.

Which of the following systems does not display emergent properties? a. A colony of bees b. A drop of water c. A calculator d. None of the listed responses is correct.

Why does a full bathtub have more thermal energy than a pot of freshly brewed coffee (even though the coffee has a higher temperature than the bathwater)? a. lower; low temperature b. lower; low density c. higher; high kinetic energy d. higher; greater volume

Why does ice float in liquid water? a. The crystalline lattice of ice causes it to be denser than liquid water. b. Ice always has air bubbles that keep it afloat. c. The ionic bonds between the molecules in ice prevent the ice from sinking. d. Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water. e. The high surface tension of liquid water keeps the ice on top.

Why is the increasing amount of carbon dioxide being taken up by the oceans a cause for concern? a. The buffering action of carbonic acid (H2CO3) causes the pH of seawater to rise. b. There is no cause for concern. Carbonic acid (H2CO3) is an excellent buffer and will help keep the pH of seawater constant. c. More carbon dioxide causes an increase in carbonic acid (H2CO3), which leads to an increase in the concentration of carbonate ion (CO32-). d. More carbon dioxide causes an increase in carbonic acid (H2CO3), which leads to a decrease in the concentration of carbonate ion (CO32-).

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

You have a freshly prepared 0.1 M glucose solution. Each liter of this solution contains how many glucose molecules? A) 6.022 × 10^23 B) 3.011 × 10^23 C) 6.022 × 10^24 D) 6.022 × 10^22

You need to represent a molecule to best illustrate the relative sizes of the atoms involved and their interrelationships. Which representation would work best? A) molecular formula B) structural formula C) ball-and-stick model D) space-filling model

A(n) _____ bond joins these two oxygen atoms. a. single covalent b. quadruple covalent c. ionic d. hydrogen e. double covalent

Because organisms are made primarily of water, they resist rapid temperature changes. This useful quality is based on water's __________. a. properties as a solvent. b. buffering activity c. cohesion d. lower density in the solid phase e. high specific heat

Compared to covalent bonds, ionic bonds ... a. are more stable in water. b. have less bond energy. c. are more abundant in biological molelcules. d. are stronger. e. rely much less on electron-sharing.

Each water molecule is joined to _____ other water molecules by ____ bonds. a) two ... polar covalent b) three ... ionic c) four ... polar covalent d) two ... hydrogen e) four ... hydrogen

Many of water's emergent properties, such as its cohesion, high specific heat, and high heat of vaporization, result from the fact that water molecules __________. a. tend to repel each other b. are very small c. are extremely large d. are in constant motion e. are attracted to each other by partial negative and positive charges on the oxygen and hydrogen atoms, respectively

Pasteur's experiments proved that (a) In order to grow, cells need to be supplied with oxygen (b) Spontaneous generation can only occur if nutrient broth is left open to the environment (c) Cells cannot survive in swan necked flasks (d) Sterilizing nutrient broth prevents spontaneous generation (e) Pre-existing cells present in the air can grow in sterilized nutrient broth

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

The atoms of different phosphorus isotopes _____. a. have different numbers of electrons b. have different atomic numbers c. react differently with other atoms d. have different numbers of protons e. have different numbers of neutrons

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

Water is a source of ______________ for chemical reactions in cells. (a) hydrogen atoms (b) oxygen atoms (c) energy (e) Both (a) and (b) (d) (a), (b), and (c).

Which of the following are qualities of any good scientific hypothesis? 1. It is testable. 2. It is falsifiable. 3. It produces quantitative data. 4. It produces results that can be replicated. a. I only b. II only c. III only d. III & IV e. I & II

Which of the following is a hydrophobic material? a. sugar b. table c. salt d. paper e. wax

Which of the following subatomic particles always has a positive charge? a. neutron b. element c. atom d. electron e. proton

Which of the following would be regarded as compounds? a. O2 and CH4 b. H2O and O2 c. H2O, O2, and CH4 d. CH4 and O2, but not H2O e. H2O and CH4, but not O2

BIO Test 1

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