PRACTICE QUIZ CHAP. 3

A molecule that has all nonpolar covalent bonds would be _____. 1) hydrophobic 2) hydrophilic 3) acidic 4) basic (alkaline) 5) ionic

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Because molecules of water are farther apart in ice than in liquid water, _____. 1) ice floats 2) ice is denser than liquid water 3) ice expands when it melts 4) ice vaporizes before liquid water does 5) all of the above

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Hydrophilic substances, but not hydrophobic substances, _____. 1) have charges and partial charges to which water molecules can adhere 2) have a higher bond energy than water 3) give up electrons to solvents 4) accept electrons from solvents 5) are repelled by water

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Pure water has a pH of 7. Why does uncontaminated rainwater have a pH of 5.6? 1) formation of carbonic acid from carbon dioxide and water 2) presence of sulfuric acid 3) presence of nitric acid 4) burning of fossil fuels 5) none of the above

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The amount of heat required to change the temperature of 1 g of any substance by °C is defined as _____. 1) the specific heat of that substance 2) 1 calorie 3) the heat of vaporization of that substance 4) 1 kilocalorie 5) molecular cohesion

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The partial charges on a water molecule occur because of _____. 1) the unequal sharing of electrons between the hydrogen and the oxygen atoms of a water molecule 2) the achievement of a stable configuration by one atom of a bond but not by the other partner 3) covalent bonding 4) widespread ionization 5) the high electronegativity of hydrogen

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The phenomenon responsible for the maintenance of a column of water as it moves upward through a vessel is _____. 1) cohesion 2) adhesion 3) surface tension 4) evaporation 5) heat of vaporization

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Water is a polar molecule. This means that _____. 1) the opposite ends of the molecule have opposite electrical charges 2) water molecules are linear, like a pole 3) water is one of the many hydrophobic molecules 4) the atoms in water have equal electronegativities 5) all of the above

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Water is a very versatile solvent because water molecules are_____. 1) polar 2) nonpolar 3) ionic 4) hydrophobic 5) volatile

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Water striders are common insects that can skip across the surface of ponds and streams. This lifestyle is enabled by water's _____. 1) cohesion and resulting surface tension 2) high specific heat 3) adhesion 4) none of the above

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Why are cell membranes composed primarily of hydrophobic molecules? 1) In order to perform their function of separating the aqueous solutions outside of cells from the aqueous solutions inside of cells, cell membranes cannot be soluble in water. 2) Cell membranes must be composed of polar molecules in order to interact with the aqueous solutions inside of cells. 3) In order to maintain a proper pH, cell membranes must be hydrophobic. 4) Cell membranes must be hydrophobic in order to form colloids. 5) Cell membranes must be composed of nonpolar molecules in order to form a hydration shell around the cell.

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You can fill a glass of water to just slightly above the rim without it spilling over the glass. What property of water best explains this phenomenon? 1) surface tension 2) adhesion 3) its polarity 4) evaporative cooling 5) none of the above

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A substance that minimizes changes in the concentration of H+ and OH- in a solution is a(n) ______. 1) hydrocarbon 2) buffer 3) NaCl 4) strong acid 5) strong base

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Adding a base tends to _____ of a solution. 1) lower the hydrogen ion concentration and lower the pH 2) lower the hydrogen ion concentration and increase the pH 3) increase the hydrogen ion concentration and lower the pH 4) increase the hydrogen ion concentration and increase the pH 5) lower the hydroxide ion concentration and lower the pH

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Adding acid tends to ____ of a solution. 1) increase the hydrogen ion concentration and raise the pH 2) increase the hydrogen ion concentration and lower the pH 3) decrease the hydrogen ion concentration and raise the pH 4) decrease the hydrogen ion concentration and lower the pH 5) either increase or decrease the pH, depending on the original acidity

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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? 1) Organisms would be able to live in a much wider range of temperatures. 2) Systems for temperature regulation would have to be much more efficient. 3) Living organisms would have to be much smaller. 4) Warm-blooded organisms would require less insulation such as fur or feathers. 5) none of the above

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Most of water's unique features (for example, its versatility as a solvent, ability to moderate temperature, and cohesive behavior) result from the fact that _____. 1) hydrogen is the only element without any neutrons 2) oxygen attracts electrons more than hydrogen does 3) oxygen has only one stable isotope, but hydrogen has three 4) oxygen has two unfilled electron shells 5) More than one of the above is correct.

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Some substances, such as oil and gasoline, will not dissolve in water because _____. 1) their molecules are so large 2) their molecules have no charges or partial charges to which water molecules can adhere 3) they do not ionize 4) their electrons are so stable that they do not exchange atoms with water molecules 5) oil and gasoline are organic compounds

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The bonds that are broken when water vaporizes are 1) ionic bonds. 2) hydrogen bonds between water molecules. 3) covalent bonds between atoms within water molecules. 4) polar covalent bonds. 5) nonpolar covalent bonds.

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Water molecules have _____ than molecules of similar size, such as ammonia and methane. 1) lower specific heat 2) a higher boiling point 3) a lower melting point 4) a lower capacity for forming hydrogen bonds 5) less surface tension

2

Water readily sticks to many other substances, a property called ______. 1) cohesion 2) adhesion 3) polarity 4) hydrophobic bonding

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Which best describes how charges are distributed on a water molecule? 1) The oxygen end is positive relative to the end with the two hydrogen atoms. 2) The oxygen end is negative relative to the end with the two hydrogen atoms. 3) The charge is neutral and equal throughout the molecule. 4) The oxygen end is neutral; one of the hydrogen atoms has a slight positive charge and the other hydrogen atom has a slight negative charge

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Which of the following statements is true about acid precipitation? 1) It harms aquatic life, but has little effect on terrestrial life. 2) It washes away some minerals that are plant nutrients, while causing some toxic minerals to accumulate. 3) Automobile use is the leading contributor to acid rain. 4) Industrial areas are hit hardest by acid rain. 5) none of the above

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A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.) 1) 50°C 2) 5°C 3) 10°C 4) 100°C 5) 1°C

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A solution at pH 6 contains ____ than the same amount of solution at pH 8. 1) 2 times more H+ 2) 4 times more H+ 3) 100 times more H+ 4) 4 times less H+ 5) 100 times less H+

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How does the polarity of water contribute to its ability to dissolve so many substances? 1) Water's polarity allows it to form covalent bonds with many substances 2) Natural water has a pH of approximately 5.6, which is slightly acidic. Acids can dissolve more substances than bases. 3) Because it is polar, water's oppositely charge ends are attracted to positively and negatively charged ions and molecules. Water molecules form a hydration shell around oppositely charged particles. 4) Because it is polar, water forms ionic bonds with the ions in substances such as NaCl (salt). 5) Because it is polar, water is able to interact with and dissolve hydrophobic substances.

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Hydrophobic molecules are _____ water. 1) attracted to 2) absorbed by 3) repelled by 4) neutralized by 5) polarized by

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In a group of water molecules, hydrogen bonds form between _____. 1) two hydrogen atoms in different water molecules 2) the oxygen atoms in different water molecules 3) the oxygen atom in one water molecule and a hydrogen atom in another water molecule 4) the hydrogen atoms in a single water molecule 5) none of the above

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Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake? 1) 4.0 M 2) 10-10 M 3) 10-4 M 4) 104 M 5) 4%

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Nonpolar molecules that cluster away from water molecules are called _____ molecules. 1) ionic 2) hydrophilic 3) hydrophobic 4) saponified 5) none of the above

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Relative to other substances, water tends to resist changes in temperature. Why? 1) Water is extremely dense, and like all dense materials, it can absorb a great deal of heat with a relatively small change in temperature. 2) Water is abundant. Large bodies of water resist changes in their temperature simply because they are massive objects. 3) Water is highly cohesive. Its molecules tend to resist increases in their motion. When water is heated, some of the energy is used to disturb the hydrogen bonds between neighboring molecules. 4) Water is highly adhesive. Pure water does not resist temperature change, but if water is bonded to other substances, molecules will tend to "stay put" and resist increases in their motion.

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Sweating has a cooling effect because of water's high _____. 1) Buffering capacity 2) surface tension 3) heat of vaporization 4) specific heat 5) density

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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 _____. 1) both caused by water's ability to form covalent bonds with hydrophobic substances 2) due to water's partial charges and low molecular mass, respectively 3) both caused by water's partial charges 4) both caused by water's two electron shells and the opposite spins of those shells 5) both due to water's low molecular mass

3

The amount of heat required to convert 1 g of any substance from the liquid to the gaseous state is defined as _____. 1) the specific heat of that substance 2) 1 calorie 3) the heat of vaporization of that substance 4) the heat of fusion of that substance 5) molecular cohesion

3

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their 1) mass in daltons. 2) mass in grams. 3) number of molecules. 4) number of atoms. 5) volume.

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What do cohesion, surface tension, and adhesion have in common with reference to water? 1) All are results of the structure of the hydrogen atom. 2) All are produced by covalent bonding. 3) All are properties related to hydrogen bonding. 4) All have to do with ionic interactions. 5) All are aspects of a crystalline structure.

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What is the hydroxide ion concentration of the lake described in question 7? 1) 10-7 M 2) 10-4 M 3) 10-10 M 4) 10-14 M 5) 10 M

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When the pH of a solution shifts from 7 to 3, how has the hydrogen ion concentration changed? 1) It has increased by 4 times. 2) It has decreased by 4 times. 3) It has increased by 10,000 times. 4) It has decreased by 10,000 times. 5) It has not changed.

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Which of the following dissociations is that of an acid? 1) H2O → H+ + OH- 2) NaOH → Na+ + OH- 3) HF → H+ + F- 4) NH3 + H+ → NH4+ 5) KOH → K+ + OH-

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Which of the following is a hydrophobic material? 1) paper 2) table salt 3) wax 4) sugar 5) pasta

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Why is the increasing amount of carbon dioxide being taken up by the oceans a cause for concern? 1) The buffering action of carbonic acid (H2CO3) causes the pH of seawater to rise. 2) More carbon dioxide causes an increase in carbonic acid (H2CO3) which leads to an increase in the concentration of carbonate ion (CO32-). 3) More carbon dioxide causes an increase in carbonic acid (H2CO3) which leads to a decrease in the concentration of carbonate ion (CO32-). 4) There is no cause for concern. Carbonic acid (H2CO3) is an excellent buffer and will help keep the pH of seawater constant. 5) none of the above

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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? 1) 92 g 2) 9.2 g 3) 0.92 g 4) 0.092 g 5) 0.0092 g

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Adhesion is best described as _____. 1) a property of water that helps moderate Earth's temperature 2) the process by which a crystalline lattice forms 3) the process that contributes to the transport of water and dissolved nutrients in plants by causing water molecules to tug on other water molecules 4) the clinging of one substance to another substance 5) none of the above

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An acid is _____. 1) any compound with a pH 2) any compound that accepts hydrogen ions 3) a material that resists changes in the pH of a solution 4) a compound that donates hydrogen ions to a solution 5) a solution with a pH between 7 and 14

4

How many grams of acetic acid (C2H4O2) would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.) 1) 10.0 g 2) 0.1 g 3) 6.0 g 4) 60.0 g 5) 0.6 g

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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? 1) water's change in density when it condenses 2) water's ability to dissolve molecules in the air 3) the release of heat by the formation of hydrogen bonds 4) the absorption of heat by the breaking of hydrogen bonds 5) water's high surface tension

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The reason that coastal climates are more moderate than inland climates is due primarily to water's high _____. 1) heat of fusion 2) surface tension 3) heat of vaporization 4) specific heat 5) density

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Water is sometimes called the "universal solvent." Is that accurate? 1) Certainly. Water's polar nature means that it can adhere to and dissolve all other substances. 2) Not at all. Only salts and carbohydrates can be dissolved in water. 3) For the most part. Water readily dissolves hydrophobic substances, but not hydrophilic ones. 4) For the most part. Water readily dissolves most substances, but not hydrophobic ones.

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Which action would involve the greatest transfer of heat? 1) changing the temperature of 1 g of water from 10°C to 90°C 2) cooling 10 g of water from 80°C to 40°C 3) evaporating 1 g of water at 25°C 4) condensing 5 g of steam to liquid water 5) raising the temperature of 10 g of ethyl alcohol by 25°C

4

A glass of grapefruit juice, at pH 3, contains _____ H+ as a glass of tomato juice, at pH 4. 1) one-tenth as much 2) half as much 3) twice as much 4) three times as much 5) ten times as much

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Cells are surrounded by water, and cells themselves consist of about 70% to 95% water. As a result _____. 1) the temperature of living things tends to change relatively slowly 2) a variety of nutrient molecules are readily available as dissolved solutes 3) waste products produced by cell metabolism can be easily removed 4) dissolved substances can be easily transported within a cell or between cells in multicellular organisms 5) all of the above

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Sucrose has a molecular mass of 342 daltons. To make a 2-molar (2 M) solution of sucrose, _____. 1) 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 2) 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 3) 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 4) 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 2 L 5) 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

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The tendency of water molecules to stay close to each other as a result of hydrogen bonding _____. 1) provides the surface tension that allows leaves to float on water 2) is called cohesion 3) keeps water moving through the vessels in a tree trunk 4) acts to moderate temperature 5) all of the above

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