Biology Chapter 2: The Atoms And Molecules Of Ancient Earth

Front 1

Chemical Evolution

Back 1

Simple chemical compounds in the atmosphere & oceans combined to form larger and more complex molecules, which led to the origin of life

Front 2

What two major events happened as the Earth began to cool?

Back 2

1. Water rained out of the atmosphere to form the first ocean
2. Many volcanoes existed, which spewed volcanic gas into the atmosphere

Front 3

What is the important characteristic of the outer-most shell of the valence electrons?

Back 3

The number of unpaired electrons (or valence) is very important for chemical bonding patterns.

Front 4

Describe covalent bonding patterns

Back 4

Valence electrons are shared between 2 atoms, which bind together to form molecules; equal sharing forms non-polar molecules/ unequal = polar.

Front 5

Electronegativity

Back 5

The degree with which atom's share their valence electrons in covalent bonds.

Front 6

Describe ionic bonds

Back 6

Valence electrons are completely transferred from one atoms to another; ions form, bonding them together.

Front 7

What is the difference between cations and anions?

Back 7

Cations- Positively charged ions

Anions- Negatively charged ions

Front 8

In a molecule, what dicates the behavior and function?

Back 8

The overall shape (bond angles).

Front 9

Molecular Formula

Back 9

The number and type of atoms in a molecule.

Front 10

Structural Formula

Back 10

Which atoms are bonded together; single, double, and triple bonds are shown by single, double, and triple dashes.

Front 11

Molecular Weight

Back 11

The sum of the mass numbers of all the atoms in a molecule.

Front 12

Molarity

Back 12

The number of moles of a substance per Liter.

Front 13

Chemical Reaction

Back 13

An event in which one substance is combined with others or broken down into another substance.

Front 14

T/F Changing the concentration of the reactants or of the products can disturb the chemical equilibrium.

Back 14

True.

Front 15

Eplain the difference between endo and exothermic reactions.

Back 15

Endothermic- Heat is absorbed in the chemical process; driven to right
Exothermic- Heat is released; equilibrium driven to left.

Front 16

Energy

Back 16

The capacity to do work or supply heat; exists either as stored potential energy or active motion.

Front 17

Thermal Energy

Back 17

The kinetic energy of molecular motion.

Front 18

Temperature

Back 18

The measure of how much thermal energy its molecules pocess.

Front 19

Heat

Back 19

The transferrence of thermal energy from one molecule to another.

Front 20

What happens when an electron 'falls' into a lower electron shell?

Back 20

It experiences a loss of potential energy because it uses some it its kinetic energy in the fall.

Front 21

First Law of Thermodynamics

Back 21

Energy is converted from one form to another; it can neither be created or destroyed.

Front 22

Second Law of Thermodynamics

Back 22

Entropy always increases in a closed system.

Front 23

Chemical Energy

Back 23

The potential energy stored in chemical bonds.

Front 24

What makes reactions spontaneous?

Back 24

1. Products have lower potential energy than reactants (exothermic) (H)
2. Products are less ordered than reactants (increased entropy) (S)

Front 25

Gibbs Free-energy change

Back 25

Delt G = Delta H - T Delta S, where T stands for the temperature in Kelvin; if G is greater than 0, the reaction is non-spontaneous; if 0, there is equilibrium.

Front 26

Why is sunlight important for the theory of chemical evolution?

Back 26

Energy from photons can break molecules apart by knocking electrons out of the outer shell of atoms.

Front 27

Free Radicals

Back 27

The resulting atoms, which have unpaired electrons and are extremely unstable.

Front 28

What 2 things can speed up reaction times?

Back 28

1. Higher temperature

2. Greater concentration

Front 29

Explain the difference between reducton and oxidation.

Back 29

Reduction is the gaining of an electron and oxidation is the loss of an electron; OIL RIG --> Oxidation is loss, Reduction is gain (often adding/losing Hs)

Front 30

Why does water have such a high specific heat?

Back 30

It takes an extraordinarily large amount of energy to break the hydrogen bonds.

Front 31

Specific Heat

Back 31

The amount of energy required to raise the temperature of a substance by 1 degree Celcius

Front 32

Explain the difference between acids and bases

Back 32

Acids give up a proton during chemical reactions; Bases acquire a proton during chemical reactions
PH is determined by -log[H+]

Front 33

Air (dry)

Back 33

1.01

Front 34

Aluminum

Back 34

.90

Front 35

Cooper

Back 35

.39

Front 36

Gold

Back 36

.13

Front 37

Iron

Back 37

.45

Front 38

Mercury

Back 38

.14

Front 39

Table Salt

Back 39

.86

Front 40

Water (s)

Back 40

2.03

Front 41

Water (l)

Back 41

4.18