Bio 102 3

29) The molecular weight of water is 18 daltons. What is the molarity of 1 liter of pure water?

A) 55.6M

17) One mole (mol) of a substance is

E) A and D only

23) How many grams of the molecule in Figure 3.2 would be equal to 1 mol of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1)

C) 60

26) A small birthday candle is weighed, then lighted and placed beneath a metal can containing 100 mL of water. Careful records are kept as the temperature of the water rises. Data from this experiment are shown on the graph. What amount of heat energy is released in the burning of candle wax?

A) 0.5 kilocalories per gram of wax burned

48) Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion concentration of this lake?

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

53) Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O → H2CO3. Carbonic acid (H2CO3) is a weak acid. Respiring cells release CO2. What prediction can we make about the pH of blood as that blood first comes in contact with respiring cells?

A) Blood pH will decrease slightly.

47) 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 (HCO 3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+

A) a decrease in the concentration of H2CO3 and an increase in the concentration of H2O.

38) Which of the following solutions has the greatest concentration of hydrogen ions [H +]?

A) gastric juice at pH 2

16) Hydrophobic substances such as vegetable oil are

A) nonpolar substances that repel water molecules.

36) What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-12 M?

A) pH 2

15) Based on your knowledge of the polarity of water molecules, the solute molecule is most likely

A) positively charged.

27) Identical heat lamps are arranged to shine on identical containers of water and methanol (wood alcohol), so that each liquid absorbs the same amount of energy minute by minute. The covalent bonds of methanol molecules are non-polar, so there are no hydrogen bonds among methanol molecules. Which of the following graphs correctly describes what will happen to the temperature of the water and the methanol?

B dot not

24) How many grams of the molecule in Figure 3.2 would be required to make 1 L of a 0.5 M solution of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1)

B) 30

13) At what temperature is water at its densest?

B) 4°C

6) Which of the following effects is produced by the high surface tension of water?

B) A water strider can walk across the surface of a small pond.

22) The molecular mass of glucose (C6H12O6) is 180 g. Which of the following procedures should you carry out to make a 0.5 M solution of glucose?

B) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L.

31) Which of the following ionizes completely in solution and is considered to be a strong acid?

B) HCl

7) Which of the following takes place as an ice cube cools a drink?

B) Kinetic energy in the drink decreases.

2) 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?

B) a hydrogen bond

3) An example of a hydrogen bond is the bond between

B) the H of one water molecule and the O of another water molecule.

55) Equal volumes of vinegar from a freshly-opened bottle are added to each of the following solutions. After complete mixing, which of the mixtures will have the highest pH?

C) 100 mL of household cleanser containing 0.5M ammonia

20) 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 particles (molecules or ions)?

C) 1Lof1.0 MNaCl

28) You have a freshly-prepared 0.1M solution of glucose in water. Each liter of this solution contains how many glucose molecules?

C) 6.02 × 1024

30) You have a freshly-prepared 1M solution of glucose in water. You carefully pour out a 100 mL sample of that solution. How many glucose molecules are included in that 100 mL sample?

C) 6.02 × 1024

57) You have two beakers. One contains a solution of HCl at pH = 1.0. The other contains a solution of NaOH at pH = 13. Into a third beaker, you slowly and cautiously pour 20 mL of the HCL and 20 mL of the NaOH. After complete stirring, the pH of the mixture will be

C) 7.0.

56) 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.

C) NaCl crystals will dissolve readily in water but will not dissolve in methanol.

10) Waterʹs high specific heat is mainly a consequence of the

C) absorption and release of heat when hydrogen bonds break and form.

34) A given solution contains 0.0001(10-4) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution?

C) acidic: H+ donor

41) If the pH of a solution is increased from pH 5 to pH 7, it means that the

C) concentration of OH- is 100 times greater than what it was at pH 5.

1) In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by

C) polar covalent bonds.

4) Water is able to form hydrogen bonds because

C) the bonds that hold together the atoms in a water molecule are polar covalent bonds.

51) Pure, freshly-distilled water has a pH of 7. This means that

C) the concentration of H+ ions in the water equals the concentration of OH- ions in the water.

12) Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?

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

42) One liter of a solution of pH 2 has how many more hydrogen ions (H+) than 1 L of a solution of pH 6?

D) 10,000 times more

9) The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius?

D) 10.0°C

25) How many grams of the molecule in Figure 3.2 would be required to make 2.5 L of a 1 M solution of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1)

D) 150

14) Why does ice float in liquid water?

D) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.

33) Which of the following statements is completely correct?

D) NH3 is a weak base (alkali), and HCl is a strong acid.

44) Which of the following statements is true about buffer solutions?

D) They maintain a relatively constant pH when either acids or bases are added to them.

11) Which type of bond must be broken for water to vaporize?

D) hydrogen bonds

5) What gives rise to the cohesiveness of water molecules?

D) hydrogen bonds

37) What is the pH of a solution with a hydrogen ion [H+] concentration of 10-8 M?

D) pH 8

46) One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+

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

8) Which of the following statements correctly defines a kilocalorie?

D) the amount of heat required to raise the temperature of 1 kg of water by 1°C

49) Research indicates that acid precipitation can damage living organisms by

D) washing away certain mineral ions that help buffer soil solution and are essential nutrients for plant growth.

43) One liter of a solution pH 9 has how many more hydroxyl ions (OH -) than 1 L of a solution of pH 4?

E) 100,000 times more

18) How many molecules of glucose (C6H2O6 molecular mass =180 daltons) would be present in one mole of glucose?

E) 6.02 × 1023

19) How many molecules of glycerol (C3H8O3) would be present in 1 L of a 1 M glycerol solution?

E) 6.02 × 1023

40) If the pH of a solution is decreased from 9 to 8, it means that the

E) Both B and D are correct.

45) Buffers are substances that help resist shifts in pH by

E) Both B and D are correct.

21) The molecular mass of glucose is 180 g. Which of the following procedures should you carry out to make a 1 M solution of glucose?

E) Dissolve 180 g of glucose in water, and then add more water until the total volume of the solution is 1 L.

32) Which of the following ionizes completely in solution and is considered to be a strong base (alkali)?

E) NaOH

50) 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

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

54) A 100 mL beaker contains 10 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 results of this mixing?

E) The pH of the beakerʹs contents falls.

35) A solution contains 0.0000001(10-7) moles of hydroxyl ions [OH-] per liter. Which of the following best describes this solution?

E) neutral

39) Which of the following solutions has the greatest concentration of hydroxyl ions [OH-]?

E) seawater at pH 8

52) Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O → H2CO3. Carbonic acid (H2CO3) is a weak acid. If CO2 is bubbled into a beaker containing pure, freshly-distilled water, which of the following graphs correctly describes the results?

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