water & life (3)

Question 1

_… allows water molecules to form hydrogen bonds with each other

Answer 1

Polarity

Question 2

The oxygen region of the h20 molecule has a … charge

Answer 2

partially negative

Question 3

The hydrogen regions of the h2O molecule have a — charge

Answer 3

partial positive

Question 4

A water molecule is a ___ molecule in which opposite ends of the molecule have ___ charges

Answer 4

polar
opposite

Question 5

oxygen is __more/less__ electronegative than hydrogen
the polar covalent bonds spend more time near the… than the…

Answer 5

more
oxygen, hydrogen

Question 6

Water molecule:
shaped like a ____
with its (number)… atom(s) and (number) ___ atom(s)
joined by _______ bonds

Answer 6

h2O
v
2 hydrogen, 1 oxygen
single polar covalent

Question 7

four emergent properties of water that contribute to
Earth’s suitability for life

Answer 7

cohesive behavior
ability to moderate temperature
expansion upon freezing
versatility as a solvent

Question 8

cohesion

Answer 8

collectively, hydrogen bunds hold water molecules together

Question 9

Surface tension

Answer 9

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

Question 10

cohesion creates low or high surface tension

Answer 10

high

Question 11

Adhesion

Answer 11

an attraction between different substances
ex. between water and plant cell walls
Helps counter downward pull ofgravity

Question 12

cohesion contributes to

Answer 12

the transport of water and dissolved nutrients against gravity in plants
Holds water together while adhesion does its job

Question 13

Kinetic energy

Answer 13

the energy of motion

Question 14

water… heat to/from warm air and

Answer 14

absorbs
from
Releases stored heat to cooler air

Question 15

Thermal energy

Answer 15

The kinetic energy associated w/ random motion of atoms or molecules

Question 16

Temperature

Answer 16

represents the average kinetic energy of the molecules in a body of matter

Question 17

heat

Answer 17

thermal energy in transfer from 1 body of matter to another

Question 18

a calorie

Answer 18

is the amount of heat required to raise the temperature of 1 g of water by 1°C
amount of heat released from 1g of water by 1°C

Question 19

“calories” on food packages is actually ___

Answer 19

Kilocalories

Question 20

Joule is

Answer 20

another unit of energy

Question 21

1J = ___ calories

Answer 21

0.239

Question 22

1 cal= ___ J

Answer 22

4.184

Question 23

specific heat of a substance is…

Answer 23

the amount of heat that must be absorbed or lost for 1g of that substance to change its temp by 1°c
1 cal/(g./°C)

Question 24

water resists changing its temp bc

Answer 24

of its high specific heat

Question 25

Water's high specific heat can be traced to

Answer 25

hydrogen bonding

Question 26

heat is absorbed whe(in water)

Answer 26

hydrogen bonds break

Question 27

heat is released when

Answer 27

hydrogen bonds form

Question 28

how is the air temp moderated in Coastal areas

Answer 28

a large body of water gathers heat during the day & summer, while only changing a few degrees, releasing it during the winter and night as the water cools

Question 29

solution

Answer 29

a liquid that is a completely homogeneous mixture of substances

Question 30

solvent

Answer 30

the dissolving agent of a solution

Question 31

solute

Answer 31

the substance that is dissolved

Question 32

aqueous solution

Answer 32

one in which water is the solvent

Question 33

Why is water an effective solvent

Answer 33

it readily forms hydrogen bonds w/ charged and polar covalent molecules

Question 34

a hydration shell

Answer 34

each dissolved ion (na and cl from NaCl) is surrounded by a sphere of water molecules

Question 35

Hydrophilic substance

Answer 35

One that has an affinity for water

Question 36

Hydrophobic substance

Answer 36

One that does not have an affinity for water

Question 37

Lol molecules are hydrophobic because they have relatively more _____ bonds

Answer 37

Nonpolar

Question 38

The major ingredients of cell membranes

Answer 38

Hydrophobic molecules

Question 39

We use _____ to calculate the number of solute molecules in an aqueous solution

Answer 39

Mass

Question 40

Molecular mass

Answer 40

The sum of all masses of all atoms in a molecule

Question 41

1mol = _____x ____ molecules

Answer 41

6.02x 10^23

Question 42

The number of molecules are usually measured un

Answer 42

Moles

Question 43

1 mole = __ g

Answer 43

1

Question 44

Molarity

Answer 44

The number of moles of solute per liter of solution

Question 45

Hydrogen ion (H+)

Answer 45

The proton when a hydrogen atom leaves it's electron behind and is transferred as a proton

Question 46

Hydroxide ion (OH-)

Answer 46

The molecule that lost the (H+) proton

Question 47

Hydronium ion (H3O+)

Answer 47

The molecule that gained the (H+) proton Often represented as H+

Question 48

pH scale

Answer 48

Describes whether a solution is acidic or basic

Question 49

At equilibrium, the concentration of H+ and OH- is

Answer 49

10^-7 M (@ 25°C)

Question 50

Acid

Answer 50

A substance that increases the H+ concentration of a solution

Question 51

Base

Answer 51

A substance that reduced the H+ concentration of a solution

Question 52

Hydrochloric acid

Answer 52

Strong acid

Question 53

Sodium hydroxide

Answer 53

Strong base

Question 54

Ammonia

Answer 54

Weak base

Question 55

Carbonic acid

Answer 55

Weak acid

Question 56

pH of acid solutions

Answer 56

Less than 7

Question 57

pH of base solutions

Answer 57

Greater than 7

Question 58

pH range for most biological fluids

Answer 58

6-8

Question 59

The internal pH of most living cells is close to

Answer 59

7

Question 60

The pH of human blood is close to

Answer 60

7.4

Question 61

A person can not survive more than a few minutes if the pH of their blood

Answer 61

drops to 7 or rises to 7.8

Question 62

Buffers

Answer 62

substances that minimize changes in concentrations of H+ and OH- resists changes in ple when either are added to a solution.

Question 63

Buffers typically consist of--- that...

Answer 63

a weak acid and its corresponding base accept & donate hydrogen ions to balance the pH.

Question 64

carbonic acid (H3CO3)

Answer 64

formed when CO2 reacts with water in blood plasma one importqant buffer in human blood and other biological solutions

Question 65

how carbonic acid acts as a buffer

Answer 65

dissociates to yield bicarbonate ion (HCO3-) and a hydrogen ion (H+) chemicla equilibrium between carbonic acid and bicarbonate acts as a pH regulator the equilibrium shifts left or right as other metabolic processes add or remove h+ from the solution