Chapter 3: Water And The Fitness Of The Environment

Front 1

Unequal distribution of electrons where the two ends of the molecule have opposite charges. (H20)

Back 1

Polar Molecule:

Front 2

Nonpolar Molecule

Back 2

Molecule with equal distribution of charge

Front 3

Phenomenon where hydrogen bonds hold the substance together

Back 3

Cohesion:

Front 4

The clinging of one substance to another

Back 4

Adhesion

Front 5

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

Back 5

Surface Tension:

Front 6

Energy of motion is called?

Back 6

Kinetic

Front 7

Heat is a form of what?

Back 7

Energy

Front 8

Measure of heat intensity that represents the average kinetic energy of the molecules, regardless of volume.

Back 8

Temperature

Front 9

Which scale is used to indicate temperature?

Back 9

Celsius

Front 10

A unit of heat is called a calorie. How many cal of heat raises the temperature of 1 g of water and by how many degrees Celsius?

Back 10

1 cal of heat, to raise 1 g of water by 1 degree Celsius.

Front 11

Kilocalorie (kal) is how many cal, and will raise the temperature of how many kilograms of water to how many degrees Celsius?

Back 11

1,000 cal, is the quantity of heat required to raise the temperature of 1 kilogram of water by 1 degree Celsius.

Front 12

Specific heat of a substance is defined as what? Can you give an example?

Back 12

As the amount of heat that must be absorbed or lost for 1 g of that substance to change by 1 degree Celsius.

Ex: water: 1cal/1g/1o

Front 13

_________ is the quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state. How many cal is used to evaporate 1 g of water?

Back 13

Heat of vaporization

It takes 580 cal to evaporate 1 g of water.

Front 14

Why does evaporative cooling occur?

Back 14

It's because the “hottest” molecules, those with the greatest kinetic energy, are the most likely to leave as gas. Evaporation from sweat dissipates body temp.

Front 15

Solution

Back 15

Is a liquid that is a completely homogeneous mixture of two or more substances

Front 16

What is a solvent?

Back 16

The dissolving agent of a solution

Front 17

What is the solute?

Back 17

The substance that is dissolved

Front 18

Aqueous is a what?

Back 18

Solution in which water is the solvent.

Front 19

What are hydration shells and can you give an example?

Back 19

Are the spheres around each dissolved ion is called a hydration shell.

An example would be mixing NaCl with water.

Front 20

Hydrophilic describes what?

Back 20

Any substance that has an affinity for water

Front 21

Molecular Mass

Back 21

The sum of all masses of all the atoms in a molecule.

Front 22

Mole

Back 22

Represents an exact number of objects (6.02 x 1023)

Front 23

Molarity

Back 23

The number of moles per liter of solution is the unit of concentration most often used by biologist for aqueous solutions.

Front 24

Hydrogen ion

Back 24

(H+) a single proton with a charge of 1+ when two water molecules connect

Front 25

Acid

Back 25

Substance that increases the hydrogen ion concentration of a solution. (H+ > OH-)

Front 26

Base

Back 26

Substance that reduces hydrogen ion concentration of a solution. (H + < OH-)

Front 27

Buffers

Back 27

Substances that minimize changes in the concentration of H+ and OH- in a solution.

Front 28

Acid precipitation

Back 28

Rain, snow or fog with a pH lower the pH 5.2

Front 29

Uncontaminated rain

Back 29

Has a pH of 5.6 slightly acidic, owing to the formation of carbon acid from carbon dioxide and water.

Front 30

Hydrogen bonding

Back 30

Bonds formed when a slightly negatively charged oxygen of one water molecule is attracted to the slightly positively charged hydrogen of a nearby molecule.

Front 31

What are the four emergent properties of water?

Back 31

Cohesion

Moderation of Temperature

Insulation of Bodies of Water by Floating Ice

Solvent life.

Front 32

_____ biological fluids resist changes in pH.

Back 32

Buffers

Front 33

How are burning fossil fuels a threat to water quality on Earth?

Back 33

Emissions of oxides( lead to acid precipitation), increasing CO2, which dissolved in the oceans, lowers pH, affecting the rate of calcification on coral reefs.

Front 34

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?

Back 34

The absorption of heat by the breaking of hydrogen bonds

Front 35

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.)

Back 35

10°C

Front 36

We can be sure that a mole of table sugar and a mole of vitamin C are equal in their

Back 36

Number of molecules.

Front 37

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.)

Back 37

60.0 g

Front 38

Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake?

Back 38

10–4 M

Front 39

What is the hydroxide ion concentration of the lake described in question 7?

Back 39

10–10 M

Front 40

Which of the following is a hydrophobic material?

Back 40

Wax

Front 41

The bonds that are broken when water vaporizes are

Back 41

Hydrogen bonds between water molecules.

Front 42

Water readily sticks to many other substances, a property called ______.

Back 42

cohesion

adhesion

polarity

hydrophobic bonding

Front 43

Water is sometimes called the "universal solvent." Is that accurate?

Back 43

Certainly. Water's polar nature means that it can adhere to and dissolve all other substances.

Not at all. Only salts and carbohydrates can be dissolved in water.

For the most part. Water readily dissolves hydrophobic substances, but not hydrophilic ones.

For the most part. Water readily dissolves most substances, but not hydrophobic ones.

Front 44

Relative to other substances, water tends to resist changes in temperature. Why?

Back 44

Water is extremely dense, and like all dense materials, it can absorb a great deal of heat with a relatively small change in temperature.

Water is abundant. Large bodies of water resist changes in their temperature simply because they are massive objects.

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.

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.

Front 45

Which best describes how charges are distributed on a water molecule?

Back 45

The oxygen end is positive relative to the end with the two hydrogen atoms.

The oxygen end is negative relative to the end with the two hydrogen atoms.

The charge is neutral and equal throughout the molecule.

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.

Front 46

Water striders are common insects that can skip across the surface of ponds and streams. This lifestyle is enabled by water's _____.

Back 46

cohesion and resulting surface tension

high specific heat

adhesion

none of the above