U1 Chapter 3: Water and Life

Question 1

Polar Molecule

Answer 1

Overall, the molecule’s charge is unevenly distributed

Question 2

Cohesion

Answer 2

When hydrogen bonds hold the substance together

Question 3

Surface Tension

Answer 3

A measure of how difficult it is to stretch or break the surface of a liquid

Question 4

Adhesion

Answer 4

The clinging of one substance to another
- adhesion of water by hydrogen bonds to the molecules of cell walls help counter the downward pull of gravity

Question 5

Kinetic Energy

Answer 5

The energy of motion, atoms and molecules have kinetic energy because they are always moving (although not necessarily in any particular direction)

Question 6

Thermal Energy

Answer 6

Kinetic energy associated with the random movement of atoms or molecules

Question 7

Temperature

Answer 7

Represents the average kinetic energy of the molecules in a body of matter, regardless of volume, whereas the thermal energy of a body of matter reflects the total kinetic energy, and thus depends on the matter’s volume

Question 8

Heat

Answer 8

Thermal energy in transfer from one body of matter to another

Question 9

Calorie (cal), unit of heat

Answer 9

A calorie is the amount it takes to raise the temperature of 1 g of water by 1 degree Celsius
- it is also the amount of heat that 1 g of water releases when it cools by 1 degree celcius
- joule (J) = 0.239 cal
- 1 cal = 4.184 J

Question 10

Specific Heat

Answer 10

Amount of heat that mut be absorbed or lost for 1 g of that substance to change its temperature by 1 degree Celsius

Question 11

Heat of Vaporization

Answer 11

The quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state

Question 12

Evaporative Cooling

Answer 12

As a liquid evaporates, the surface of the liquid that remains behind cools down (its temperature decreases)
- occurs because the “hottest” molecules, those with the greatest kinetic energy, are the most likely to leave as a gas

Question 13

Solution

Answer 13

A liquid that is a completely homogenous mixture of two or more substances

Question 14

Solvent

Answer 14

The dissolving argent of a solution

Question 15

Solute

Answer 15

The substance that is dissolved

Question 16

Aqueous Solution

Answer 16

One in which the solute is dissolved in water; water is the solvent

Question 17

Hydration Shell

Answer 17

The sphere of water molecules around each dissolved ion

Question 18

Hydrophilic

Answer 18

Any substance that has an affinity for water
- polar molecules

Question 19

Hydrophobic

Answer 19

Substances that do not have an affinity for water
- nonionic and nonpolar (or otherwise cannot form hydrogen bonds) actually seam to repel water

Question 20

Molecular Mass

Answer 20

The sum of the masses of all the atoms in a molecule
- mole (mol) represents an exact number of objects: 6.02 x 10^23 which is also called Avogadro’s number

Question 21

Hydrogen Ion (H+)

Answer 21

A single proton with a charge of 1+
- the water molecule that has lost a proton is now a hydroxide ion (OH-)

Question 22

Acid

Answer 22

A substance that increases the hydrogen ion concentration of a solution

Question 23

Base

Answer 23

A substance that reduced the hydrogen ion concentration of a solution

Question 24

pH Scale

Answer 24

A measure of hydrogen ion concentration equal to -log[H+] and ranging in value from 0 to 14

Question 25

Buffer

Answer 25

A substance that minimizes changes in the concentrations of H+ and OH-

Question 26

Ocean Acidification

Answer 26

When CO2 dissolves in sea water and reacts with the water to form carbonic acid, which lowers ocean pH
- alters the delicate balance of conditions for life in the oceans