chapter three

Question 1

what makes water polar?

Answer 1

oxygen is more EN than hydrogen, so the electrons are closer to O and give it a partially negative charge
- unequal sharing of electrons

Question 2

H-bonding

Answer 2

hydrogens of water molecules attach to O of other water molecules

Question 3

cohesion

Answer 3

hydrogen bonds holding molecules together

Question 4

surface tension

Answer 4

a measure of how difficult it is to stretch/break surface of a liquid (hydrogen bonds)

Question 5

adhesion

Answer 5

the clinging of one substance to another

Question 6

adhesion and cohesion help get water up tree

Answer 6

• water adheres to walls of xylum (adhesion)
• water adheres to other water molecules (cohesion)

Question 7

kinetic energy

Answer 7

the energy of motion
- atoms/molecules always moving

Question 8

heat

Answer 8

thermal energy in transfer from one body of matter to another

Question 9

temperature

Answer 9

average kinetic energy of molecules in body of matter

Question 10

celsius scale

Answer 10

• 0 - freezing water
• 100 - boiling water

Question 11

calorie

Answer 11

amount of heat it takes to raise temperature of 1 g of water by 1 degree celsius

Question 12

kilocalorie

Answer 12

1,000 cal = 1 kcal
- amount of heat it takes to raise temperature of 1 kg of water by 1 degree celsius

Question 13

specific heat of water

Answer 13

amount of heat 1g of water must absorb to rase the temperature by 1 degree celsius

Question 14

heat of vaporization

Answer 14

amount of heat a liquid must absorb to convert 1 g of liquid to gaseous state

Question 15

evaporative cooling

Answer 15

as liquid evaporates, surface of liquid that remains cools down

Question 16

water is most dense at

Answer 16

4 degrees celsius

Question 17

solution

Answer 17

liquid that is a completely homogeneous mixture of 2+ substances

Question 18

solvent

Answer 18

dissolving agent

Question 19

solute

Answer 19

that which is dissolved

Question 20

aqueous solution

Answer 20

where solute is dissolved in water (solvent)

Question 21

hydration shell

Answer 21

sphere of water molecules around each dissolved ion

Question 22

hydrophillic

Answer 22

water loving
- cotton

Question 23

colloid

Answer 23

2+ substances mixed together but not chemically combined
- suspended particles, not homogeneous

Question 24

hydrophobic

Answer 24

repel water
- oil, cell membrane

Question 25

molecular mass

Answer 25

sum of masses of all atoms in a molecule

Question 26

mole (mol)

Answer 26

exact number of objects (molecules)
- Avogadro’s number (6.02 x 10^23)

Question 27

molarity

Answer 27

number of moles of a solution

Question 28

pH

Answer 28

measure of acidity

Question 29

pH is the _____ log of H+ concentration

Answer 29

negative

Question 30

hydrogen ion

Answer 30

H+

Question 31

hydroxide ion

Answer 31

OH-

Question 32

acid

Answer 32

increase of H+ (pH<7)

Question 33

base

Answer 33

decrease of H+ (pH>7)

Question 34

pH scale ranges from

Answer 34

0-14

Question 35

function of buffers

Answer 35

resist changes in concentration of H+ and OH-

Question 36

buffer works by

Answer 36

accepting and donating H+ ions

Question 37

ocean acidification

Answer 37

when carbon dioxide dissolves in salt water and reacts with water to form carbonic acid