Chapter 3 Biology

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

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?

The partial negative charge in a molecule of water occurs because _____. a. the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus. b. the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms 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

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. not form hydrogen bonds with each other b. have a greater tendency to from hydrogen bonds with each other c. have greater cohesion to other molecules of H2S d. have a higher capacity to absorb heat for the same change in temperature

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 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.

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. density at room temperature b. pH c. specific heat d. heat of vaporization

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 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 type of bond must be broken for water to vaporize?

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 e. charged molecules that hydrogen-bond with water molecules

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

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. 180 g of glucose and then add more water until the total volume of the solution is 1 L b. 180 g of glucose and then add 0.2 L more of water c. g of glucose and then add more water until the total volume of the solution is 1 L d. 18 g of glucose and then add more water until the total volume of the solution is 1 L

(refer to diagram) Based on your knowledge of the polarity of water molecules, the solute molecule depicted here is most likely _____.

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

Identical heat lamps are arranged to shine on two identical containers, one containing water and one methanol (wood alcohol), so that each liquid absorbs the same amount of energy minute by minute. The covalent bonds of methanol molecules are nonpolar, 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?

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.

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

A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance?

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

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.

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. an in increase in the concentration of HCO3- and a decrease in the concentration of OH- b. decrease in the concentration of HCO3- and an increase in the concentration of H+ c. an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3- d. decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-

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 hyrdoxide ions per liter of lake water b. 4.0 * 10^-4 mol of hydroxide ions per liter of lake water c. 1 * 10^-4 mol of hydroxide ions per liter of lake water' d. 4.0 M with regard to hydroxide ion concentration

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. the concentration of hydrogen ions in solution Y is 1000 times as great as the concentration of hydrogen ions in solution X b. the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y c. the concentration of hydrogen ions in solution X is 1000 times as great as the concentration of hydrogen ions in solution Y d. solution Y has no free hydrogen ions (H+)

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 pH of the beaker's contents will increase. b. The concentration of Na+ ions will rise. c. The pH of the beaker's contents will be neutral. d. The pH of the beaker's contents will decrease.

Increased atmospheric CO2 concentrations might have what effect on seawater? a. Seawater will become more acidic, and carbonate concentrations will increase. b. There will be no charge in the pH of seawater, because carbonate will turn into bicarbonate. c. Seawater will become more acidic, and the carbonate concentrations will decrease. d. Seawater will become more alkaline, and carbonate concentrations will decrease.

How would acidification of seawater affect marine organisms? Acidification of seawater would _____. a. increase dissolved carbonate concentrations and hinder growth of coral and shell-building animals b. decrease dissolved carbonate concentrations and hinder growth of coral and shell-building animals

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.

Explain the pattern of temperatures shown in the diagram. (refer to picture)