Chapter 2: The Chemical Basis Of Life

Question 0

Element

Answer 0

Substance that can’t be broken down into another substance by ordinary chemical means

Question 1

Matter

Answer 1

Refers to anything that takes up space and has mass

Question 2

Elements that make up 98% of the body weight of most organisms

Answer 2

Carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur

Question 3

Atoms

Answer 3

Smallest particle of an element that displays the properties of an element

Question 4

Atomic symbol

Answer 4

Element Name represented by one or two letters

Question 5

Neutrons

Answer 5

No electrical charge

Question 6

Protons

Answer 6

Have positive charge

Question 7

Electrons

Answer 7

Negative charge

Question 8

Nucleus

Answer 8

Center of an atom

Question 9

Atomic mass

Answer 9

Equal sum of protons and neutrons

Question 10

Atomic number

Answer 10

Atoms of the same element have the same number of protons

Question 11

Period

Answer 11

Horizontal row on periodic table

Question 12

Group

Answer 12

Vertical column in periodic table

Question 13

Isotopes

Answer 13

Atoms of the same element that differ in the number of neutrons

Question 14

Tracer

Answer 14

Substance having an attached radioactive isotope that allows a researcher to track its whereabouts in a biological system

Question 15

Electron shells

Answer 15

Concentric energy levels in which electrons orbit

Question 16

Octet rule

Answer 16

Outer shell is most stable when it has 8 electrons

Question 17

Valence she’ll

Answer 17

Atoms outer shell

Question 18

Molecule

Answer 18

Group of atoms bonded together

Question 19

Compound

Answer 19

Molecule contains atoms of more than one element

Question 20

Ionic bond

Answer 20

Forms when two atoms are held together by the attraction between opposite charges

Question 21

Ions

Answer 21

Charged atoms

Question 22

Salts

Answer 22

Compound produced by a reaction between an acid and a base

Question 23

Covalent bond

Answer 23

Results when two atoms share electrons in order to have a completed outer shell

Question 24

Reactants

Answer 24

Molecules that participate in the reaction shown on the left side of the arrow

Question 25

Products

Answer 25

Molecules formed by the reaction and shown on the right side of the arrow

Question 26

Electronegativity

Answer 26

Ability of an atom to attract electrons toward itself in a chemical bond

Question 27

Polar

Answer 27

Atoms on both sides of the bond are partially charged even though the overall molecule itself bears no net charge

Question 28

Hydrogen (H) bond

Answer 28

Weak bond that arises between a slightly positive hydrogen atom of one molecule and a slightly negative atom of another molecule or between parts of the same molecule

Question 29

Properties of water

Answer 29

Solvency, cohesion and adhesion, high surface tension, high heat capacity, high heat of vaporization, and varying density

Question 30

Hydrophilic

Answer 30

Molecules that are attracted to water

Question 31

Hydrophobic

Answer 31

Molecules not attracted to water

Question 32

Cohesion

Answer 32

Ability of water molecules to cling to each other due to hydrogen bonding

Question 33

Adhesion

Answer 33

Ability of water molecules to cling to other polar surfaces

Question 34

Hydroxide ions (OH-)

Answer 34

One of two ions that result when a water molecule dissociates and gains an electron

Question 35

When water dissociates it releases what?

Answer 35

Hydrogen ions and hydroxide ions

Question 36

Acids

Answer 36

Substances that dissociate in water releasing hydrogen ions

Question 37

Bases

Answer 37

Substances that either take up hydrogen ions or release hydroxide ions

Question 38

pH

Answer 38

Mathematical way of indicating the number of hydrogen ions in a solution

Question 39

pH scale

Answer 39

Used to indicate the acidity or basicity of a solution

Question 40

Buffer

Answer 40

Chemical or a combo of chemicals that keeps pH within normal limits