Chapter 2: The Chemical Basis of Life

Question 1

What are the three types of matter?

Answer 1

Solid, liquid and gas.

Question 2

Atoms

Answer 2

The smallest functional unit of matter that forms all chemical substances.

Question 3

Element

Answer 3

A pure substance made of only one kind of atom.

Question 4

Compound

Answer 4

Two or more different elements.
Example: H2O

Question 5

Molecule

Answer 5

Same atoms that are connected
Example: O2

Question 6

What are the three subatomic particles?

Answer 6

Protons, Neutrons, and Electrons

Question 7

Protons

Answer 7

Positive Charge and found in the nucleus

Question 8

Neutrons

Answer 8

No charge/ Neutral and are found in the nucleus.

Question 9

Electrons

Answer 9

Negative charge and found on orbitals. Participate in chemical reactions.

Question 10

How many electrons can the first orbital hold?

Answer 10

2 Electrons

Question 11

The more electrons you have the more…?

Answer 11

Power

Question 12

Valence Electrons

Answer 12

The electrons on the outer shell that are important for chemical bonds.

Question 13

To fill the outer shell

Answer 13

atoms will share, gain or lose electrons.

Question 14

Atomic number

Answer 14

Represents the number of protons

Question 15

Mass number

Answer 15

The sum of protons and neutrons.

Question 16

To find the number of neutrons you must…?

Answer 16

subtract mass number and atomic number.

Question 17

Four elements that most abundant in life are

Answer 17

Hydrogen, Oxygen, Nitrogen and Carbon

Question 18

Molecular formula

Answer 18

contains chemical symbols of the elements in the molecule.

Question 19

What are isotopes?

Answer 19

The same number of protons, different number of neutrons.
Sometimes radioactive
Used for carbon dating.

Question 20

Electronegativity

Answer 20

The measure of an atom’s ability to attract electrons in a bind with another atom.

Question 21

Octet Rule

Answer 21

Determines bonding behavior.
Stable or “complete” when the valence shell has 8 electrons.
Unstable or “incomplete” when the shell has less than 8 electrons.

Question 22

Types of molecular bonding

Answer 22

Ionic Bonds
Covalent bonds
Hydrogen bonds

Question 23

Ionic bonds

Answer 23

Atoms take an electron from another.
These are bond attractions between ions of opposite charge.
These compounds are called salts.

Question 24

Cation

Answer 24

Positive charge ion

Question 25

Anion

Answer 25

Negative charge ion

Question 26

Covalent Bonds

Answer 26

A bond forms when elements SHARE a pair of electrons. Strongest bonds. Occurs between atoms with unfilled valence electron shells.

Question 27

Polar Covalent Bonds

Answer 27

Unequal sharing of electrons. Creates polarities (difference in electric charge)

Question 28

Non-polar Covalent Bonds

Answer 28

Equal sharing of electrons, no charge difference. Happens with atoms with similar electronegativities.

Question 29

Why are covalent bonds strong chemical bonds?

Answer 29

The shared electrons behave as if they belong to each atom.

Question 30

Hydrogen Bonds

Answer 30

The hydrogen atom from one polar molecule is attracted to an electronegative atom of another.

Question 31

Chemical Reaction

Answer 31

When one or more substances are changed into other substances.

Question 32

Properties of Chemical Reactions

Answer 32

Require a source of energy (heat) In living organisms, they often use an enzyme as a catalyst (an agent that speeds up a chemical reaction) They tend to proceed in a particular direction but will eventually reach equilibrium. It usually occurs in liquids.

Question 33

What will dissolve in water?

Answer 33

Ions and molecules with polar covalent bonds.

Question 34

Solution

Answer 34

Solutes in a solvent

Question 35

Hydrophobic

Answer 35

lacking affinity for water (dislikes water, does not mix, nonpolar)

Question 36

Hydrophilic

Answer 36

having an affinity to water (to like water, polar)

Question 37

Amphipathic

Answer 37

Both hydrophilic and hydrophobic

Question 38

Hydrogen bonding explains most of the water's life's supporting properties...

Answer 38

Water as a solvent Cohesion Water moderates temperature Ice floats

Question 39

Concentration

Answer 39

The amount of a solute dissolved in a unit volume of solution.

Question 40

Molarity

Answer 40

Number of moles of a solute dissolved in water.

Question 41

Cohesion

Answer 41

attraction of identical molecules

Question 42

Water molecules stick together as a result of?

Answer 42

Hydrogen Bonding

Question 43

Surface Tension

Answer 43

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

Question 44

Adhesion

Answer 44

Ability to stick to polar surfaces.

Question 45

Water moderates temperature

Answer 45

Because of hydrogen bonding, water has a resistance to temperature change. Highest heat capacity of any liquid.

Question 46

Ice Floats

Answer 46

Water is less dense as a solid than as a liquid, this allows fish and other organisms to survive under ice. Water expands when frozen.

Question 47

Heat of Vaporazation

Answer 47

Energy to boil

Question 48

Heat to fusion

Answer 48

Energy to melt.

Question 49

Acid

Answer 49

pH = 0-7 High hydrogen concentrations Donates protons/hydrogen atoms.

Question 50

Bases (Alkaline)

Answer 50

pH= 7-14 Low hydrogen concentrations Accepts protons/hydrogen ions

Question 51

Neutral

Answer 51

pH= 7.0

Question 52

pH scale

Answer 52

Describes how acidic or basic a solution is. A measure of the concentrations of hydrogen bonds.

Question 53

The pH of a solution can affect:

Answer 53

The shapes and functions of molecules The rates of many chemical reactions The ability of two molecules to bind together. The ability of ions or molecules to dissolve in water. Small changes in pH can have a big impact on biological processes.

Question 54

Buffers are composed of

Answer 54

weak acid/base and its salt.

Question 55

The function of a buffer is

Answer 55

to reduce the change in pH when an acid or base is added.

Question 56

Waters important functions

Answer 56

Participates in chemical reactions Provides force or support Removes toxic waste Evaporative cooling Lubrication Cohesion and Adhesion