Chapter 2 - Small Molecules and the Chemistry of Life

Question 1

Atom

Answer 1

Smallest unit of matter

Question 2

Atomic Mass

Answer 2

Measurement of the quantity of matter present

Question 3

Atomic Mass Unit (AMU)

Answer 3

Mass of one proton or neutron

Question 4

Element

Answer 4

Pure substance composed of only one kind of atom

Number of protons are unique to each element

Question 5

Atomic Number

Answer 5

Number of protons

Question 6

Mass Number

Answer 6

Number of protons and number of neutrons in an atom’s nucleus

Question 7

Atomic Weight

Answer 7

Average of mass numbers of isotopes

Question 8

Isotopes

Answer 8

Forms of an element with different number of neutrons

Different mass numbers

Question 9

Hydrogen

Answer 9

Element with 1 proton, 0 neutrons

Question 10

Deuterium

Answer 10

Hydrogen isotope

1 proton, 1 neutron

Question 11

Tritium

Answer 11

Hydrogen isotope
1 proton, 2 neutrons
Heavy water

Question 12

Radioisotopes

Answer 12

Unstable isotopes that spontaneously give off energy in the form of α, β, and γ radiation from the nucleus
The release of energy transforms the original atom

Question 13

Molecule

Answer 13

Stable association of atoms

Question 14

Electron

Answer 14

Number of electrons determine how atoms will interact

Question 15

Orbital

Answer 15

Region where electrons are found 90% of the time

Can be occupied by 2 electrons

Question 16

Electron Shell

Answer 16

Energy levels around the nucleus of an atom
First shell contains one s orbital (2 electrons)
Second shell contains 1 s and 3 p orbitals (8 electrons)

Question 17

Valence Shell

Answer 17

Outermost electron shell
Determines how the atom interacts with other atoms (chemical reaction)
Reactive atoms have unpaired electrons in valence shell

Question 18

Chemical Bond

Answer 18

Attractive force that links atoms together to form molecules

Question 19

Covalent Bond

Answer 19

Sharing of at least one pair of electrons so that the outer shell is filled
Strongest of chemical bonds

Question 20

Valence

Answer 20

Number of bonds an atom can form depending on the number of valence electrons

Question 21

Compound

Answer 21

Molecule made of up two or more elements bound together in a fixed ratio

Question 22

Molecular Weight

Answer 22

Sum of all atomic weights of all atoms in the molecule

Question 23

Nonpolar Covalent Bond

Answer 23

Equal sharing of electrons

Question 24

Polar Covalent Bond

Answer 24

Unequal sharing of electrons when electrons are drawn to one nucleus more than to the other
Partial negative charge near the strongly electronegative atom
Partial positive charge near the weakly electronegative atom

Question 25

Electronegativity

Answer 25

Measure of degree of attraction between nucleus and electrons Higher value = greater attraction of pairing elctrons to the receiving nucleus

Question 26

Ion

Answer 26

Electrically charged particles that form when atoms gain or lose one or more electrons

Question 27

Cations

Answer 27

Positively charged ions; one less electron than protons

Question 28

Anions

Answer 28

Negatively charged ions; one more electron than protons

Question 29

Ionic Attraction

Answer 29

Bond formed as a result of the electrical attraction between ions of opposite charges

Question 30

Hydrogen Bond

Answer 30

Negatively charged oxygen atom of one water molecule is attracted to the positively charged hydrogen atom of another water molecule; intramolecular

Question 31

Hydrophilic Interactions

Answer 31

A polar molecule interacts with water; "water-loving"

Question 32

Hydrophobic Interactions

Answer 32

Nonpolar molecules interact with other nonpolar molecules; "water-hating"

Question 33

Chemical Reactions

Answer 33

Loss or gain of electrons, with reactants combined on the left to create products on the right

Question 34

Oxidation

Answer 34

Chemical reaction with a loss of electrons (LEO - loss of electrons equals oxidation)

Question 35

Reduction

Answer 35

Chemical reaction with a gain of electrons (GER - gain of electrons equal reduction)

Question 36

Energy

Answer 36

Capacity to do work

Question 37

Water

Answer 37

A polar molecule that can form hydrogen bonds; tetrahedral shape (not a linear shape)

Question 38

Solute

Answer 38

Substance being dissolved

Question 39

Solvent

Answer 39

Liquid that dissolves a substance

Question 40

Mole

Answer 40

Amount of substance (grams) that is numerically equal to its molecular weight; 1 mole for any substance is 6.02 x 10^-23 molecules per mole

Question 41

1 Molar Solution

Answer 41

1 mole of a substance dissolved in water to make 1 L

Question 42

Acids

Answer 42

Substances that release H+; higher concentration of H+; pH level 1-7

Question 43

Bases

Answer 43

Substances that accept H+; lower concentration of H+; pH level 7-14

Question 44

pH

Answer 44

A numeric scale used to specify the acidity or basicity of an aqueous solution; each pH value up or down represents a 10 fold increase/decrease in hydrogen ion concentration [H+]

Question 45

Buffer

Answer 45

A weak acid or base used to prevent a rapid change in pH when acids or bases are added to the solution; to maintain homeostasis