Chapter 2

Question 1

MATTER

Answer 1

Anything that occupies space and has mass.

Question 2

ELEMENT

Answer 2

A substance that cannot be broken down to other substances by chemical means.

Question 3

COMPOUND

Answer 3

A substance containing two or more elements in a fixed ratio. For example, table salt (NaCl) consists of one atom of the element sodium (Na) for every atom of chlorine (Cl).

Question 4

TRACE ELEMENTS

Answer 4

an element that occurs at very small quantities in the body but is nonetheless important for many biological processes

Question 5

ATOM

Answer 5

The smallest unit of matter that retains the properties of an element.

Question 6

PROTON

Answer 6

A subatomic particle with a single positive electrical charge, found in the nucleus of an atom.

Question 7

ELECTRON

Answer 7

A subatomic particle with a single negative electrical charge. One or more electrons move around the nucleus of an atom.

Question 8

REACTANTS

Answer 8

a substance that takes part in and undergoes change during a reaction.

Question 9

SURFACE TENSION

Answer 9

A measure of how difficult it is to stretch or break the surface of a liquid. Water has a high surface tension because of the hydrogen bonding of surface molecules.

Question 10

SOLUTE

Answer 10

A substance that is dissolved in a solution.

Question 11

BUFFERS

Answer 11

a solution that resists a change in pH when acids or bases are added.

Question 12

NEUTRON

Answer 12

A subatomic particle having no electrical charge, found in the nucleus of an atom.

Question 13

NUCLEUS

Answer 13

(1) An atom’s central core, containing protons and neutrons. (2) The organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made of chromatin.

Question 14

ATOMIC NUMBER

Answer 14

The number of protons in each atom of a particular element.

Question 15

MASS NUMBER

Answer 15

The sum of the number of protons and neutrons in an atom’s nucleus.

Question 16

ATOMIC MASS

Answer 16

The total mass of an atom; also called atomic weight. Given as a whole number, the atomic mass approximately equals the mass number.

Question 17

ISOTOPES

Answer 17

one of two or more atoms with the same atomic number but with different numbers of neutrons

Question 18

RADIOACTIVE ISOTOPE

Answer 18

An isotope whose nucleus decays spontaneously, giving off particles and energy.

Question 19

PRODUCT

Answer 19

An ending material in a chemical reaction.

Question 20

THERMAL ENERGY

Answer 20

Kinetic energy due to the random motion of atoms and molecules; energy in its most random form.

Question 21

EVAPORATIVE COOLING

Answer 21

The process in which the surface of an object becomes cooler during evaporation, a result of the molecules with the greatest energy changing from the liquid to the gaseous state.

Question 22

AQUEOUS SOLUTION

Answer 22

A solution in which water is the solvent.

Question 23

OCEAN ACIDIFICATION

Answer 23

Process by which the pH of the ocean is lowered (made more acidic) when excess atmospheric CO2 dissolves in seawater.

Question 24

ELECTRON SHELLS

Answer 24

a grouping of electrons surrounding the nucleus of an atom

Question 25

CHEMICAL BONDS

Answer 25

an electrical force linking atoms

Question 26

IONIC BONDS

Answer 26

a chemical bond in which one atom loses an electron to form a positive ion and the other atom gains an electron to form a negative ion

Question 27

COVALENT BOND

Answer 27

A type of strong chemical bond in which two atoms share one or more pairs of valence electrons.

Question 28

MOLECULE

Answer 28

Two or more atoms held together by covalent bonds. GLOSSARY

Question 29

ELECTRONEGATIVITY

Answer 29

The attraction of a given atom for the electrons of a covalent bond.

Question 30

NON POLAR COVALENT BONDS

Answer 30

A bond between 2 nonmetal atoms that have the same electronegativity and therefore have equal sharing of the bonding electron pair

Question 31

COHESION

Answer 31

The sticking together of molecules of the same kind, often by hydrogen bonds.

Question 32

ADHESION

Answer 32

The attraction between different kinds of molecules.

Question 33

HEAT

Answer 33

Thermal energy in transfer from one body of matter to another.

Question 34

TEMPERATURE

Answer 34

A measure in degrees of the average thermal energy of the atoms and molecules in a body of matter.

Question 35

SOLUTION

Answer 35

A liquid that is a homogeneous mixture of two or more substances.

Question 36

SOLVENT

Answer 36

The dissolving agent of a solution. Water is the most versatile solvent known.

Question 37

ACID

Answer 37

A substance that increases the hydrogen ion (H+) concentration in a solution.

Question 38

BASE

Answer 38

A substance that decreases the hydrogen ion (H+) concentration in a solution.

Question 39

PH SCALE

Answer 39

A measure of the acidity of a solution, ranging in value from 0 (most acidic) to 14 (most basic). The letters pH stand for potential hydrogen and refer to the concentration of hydrogen ions (H+).

Question 40

POLAR COVALENT BOND

Answer 40

A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.

Question 41

IONIC BONDS

Answer 41

a chemical bond in which one atom loses an electron to form a positive ion and the other atom gains an electron to form a negative ion

Question 42

HYDROGEN BOND

Answer 42

A type of weak chemical bond formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule (or in another region of the same molecule).

Question 43

POLAR MOLECULE

Answer 43

A molecule containing polar covalent bonds and having an unequal distribution of charges in different regions of the molecule.

Question 44

CHEMICAL REACTIONS

Answer 44

(chemistry) a process in which one or more substances are changed into others