Water, the Medium of Life - Chapter #3

Question 1

All of life’s ____ ____ take place in water

Answer 1

Chemical reactions

Question 2

A universal ____

Answer 2

solvent

Question 3

_____ biological molecules though cells, a body, or an ecosystem.

Answer 3

Transports

Question 4

Influences the ____of biological molcules

Answer 4

Shape

Question 5

Bond between H and O in water is ____

Answer 5

Covalent

Question 6

O is (more or less) electronegative than H

Answer 6

MORE

Question 7

Why do we say water is sticky

Answer 7

It’s polarity attracts it to other polar molecules

Question 8

3 Important Properties of Water

Answer 8

• Cohesive behaviour
• Ability to moderate temperature
• Versatile solvent

Question 9

Cohesive means

Answer 9

Water molecules are attracted to each other

Question 10

Ability to moderate temp means….

Answer 10

Water has a high specific heat, so it resists changes in temp

Question 11

Evaporative cooling

Answer 11

hottest molecules leave, remaining liquid cools

Question 12

Solution

Answer 12

A homogenous mixture of 2 or more substances

Question 13

Solute

Answer 13

The substance that is dissolved

Question 14

Solvent

Answer 14

The dissolving agent

Question 15

Aqueous solution

Answer 15

A solution in which the solvent is water

Question 16

Hydrophilic Substances

Answer 16

Can form hydrogen bonds with water, LOVES it!
Polar
Water dissolves them
Ex: Alcohol

Question 17

Hydrophobic

Answer 17

Hates water!
Non polar
Ex: Hydrocarbons

Question 18

Hydrophobic interactions

Answer 18

Non polar molecules aggregate in water

Question 19

Protein folds to bury _____ regions in an aqueous environment.

Answer 19

Hydrophobic

Question 20

Acids donate _____ in aqueous solutions

Answer 20

donate H+

Question 21

Bases donate ___ or accept ___ in aqueous solutions

Answer 21

Donate OH- of H+

Question 22

Solutes can alter the ___ of a solution

Answer 22

PH

Question 23

Organic acids (carboxylic) are generally \_\_\_\_ and do not \_\_\_\_
Ex??

Answer 23

Weak acids, do not completely dissociate in water

Ex: lactic acid

Question 24

Dissociation of a carboxylic acids ___ the PH of a solution

Answer 24

Decreases!

Bc H+ released, duh!

Question 25

Organic acids, often amines, accept ___

Do what to PH?

Answer 25

protons

Increase PH!

Question 26

The polarity of water enables it to…

Answer 26

Form hydrogen bonds

Question 27

Water dissolves hydrophilic substances by…

Answer 27

Forming hydrogen bonds

Question 28

Water is polar because….

Answer 28

Unequal sharing of electrons (v-like shape)

Question 29

Oxygen has a partial __ change

Answer 29

Negative (more electroneg)

Question 30

Hydrogen has a partial ___ charge

Answer 30

Positive (less electroneg)

Question 31

Describe the H bonds between water molecules

Answer 31

Partial neg of one and partial pos of other connect molecules

Question 32

It’s ok that H bonds break super easily and don’t last long because…

Answer 32

Molecules constantly forming new H bonds with a succession of partners.

Question 33

Cohesion

Answer 33

H bonds hold substance together

Question 34

Cohesion contributes to….

Answer 34

Transport of water and dissolved nutrients against gravity in plants

Question 35

Adhesion

Answer 35

Clinging of one substance to another

Counters downward pull of grav.

Question 36

Surface tension

Answer 36

How difficult it is to stretch or break the surface of a liquid
For water it is HIGH

Question 37

Water moderates air temperature by

Answer 37

absorbing heat from air that is warmer and releasing the stored heat to air that is cooler.

Question 38

Specific heat

For water?

Answer 38

The amount of heat that must be absorbed/lost for 1g to change 1 degree C
HIGH