# U1 Chapter 3: Water and Life Flashcards

1
Q

Polar Molecule

A

Overall, the molecule’s charge is unevenly distributed

2
Q

Cohesion

A

When hydrogen bonds hold the substance together

3
Q

Surface Tension

A

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

4
Q

A

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

5
Q

Kinetic Energy

A

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

6
Q

Thermal Energy

A

Kinetic energy associated with the random movement of atoms or molecules

7
Q

Temperature

A

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

8
Q

Heat

A

Thermal energy in transfer from one body of matter to another

9
Q

Calorie (cal), unit of heat

A

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

10
Q

Specific Heat

A

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

11
Q

Heat of Vaporization

A

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

12
Q

Evaporative Cooling

A

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

13
Q

Solution

A

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

14
Q

Solvent

A

The dissolving argent of a solution

15
Q

Solute

A

The substance that is dissolved

16
Q

Aqueous Solution

A

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

17
Q

Hydration Shell

A

The sphere of water molecules around each dissolved ion

18
Q

Hydrophilic

A

Any substance that has an affinity for water
- polar molecules

19
Q

Hydrophobic

A

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

20
Q

Molecular Mass

A

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

21
Q

Hydrogen Ion (H+)

A

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

22
Q

Acid

A

A substance that increases the hydrogen ion concentration of a solution

23
Q

Base

A

A substance that reduced the hydrogen ion concentration of a solution

24
Q

pH Scale

A

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

25
Q

Buffer

A

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

26
Q

Ocean Acidification

A

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