Dalton Hs Chemistry Vocabulary

Front 1

Chemistry

Back 1

The study of the structure and behavior of matter.

Front 2

Value

Back 2

A number and unit that together represent the result of a measurement or calculation. The distance of a particular race, for example, may be reported as a value of 100 meters.

Front 3

Unit

Back 3

A defined quantity based on a standard. For example, in the value 100 meters, meter is the unit.

Front 4

Base Units

Back 4

The seven units from which all other units in the SI system of measurement are derived.

Front 5

Mass

Back 5

The amount of matter in an object. Mass can also be defined as the property of
matter that leads to gravitational attractions between objects and therefore gives rise to weight.

Front 6

Weight

Back 6

A measure of the force of gravitational attraction between an object and a significantly large object, such as the earth or the moon.

Front 7

Matter

Back 7

Anything that has mass and occupies space.

Front 8

Absolute Zero

Back 8

Zero kelvins (0 K), the lowest possible temperature, equivalent to -273.15 °C. It is the point beyond which motion can no longer be decreased.

Front 9

Model

Back 9

A simplified approximation of reality.

Front 10

Solid

Back 10

The state in which a substance has a definite shape and volume at a constant temperature.

Front 11

Liquid

Back 11

The state in which a substance has a constant volume at a constant temperature but can change its shape.

Front 12

Gas

Back 12

The state in which a substance can easily change shape and volume.

Front 13

Evaporation / vaporization.

Back 13

The conversion of a liquid to a gas.

Front 14

Element

Back 14

A substance that cannot be chemically converted into simpler substances; a substance in which all of the atoms have the same number of protons and therefore the same chemical characteristics.

Front 15

Group / Family

Back 15

All the elements in a given column on the periodic table.

Front 16

Metals

Back 16

The elements that (1) have a metallic luster, (2) conduct heat and electric currents well, and (3) are malleable.

Front 17

Malleable

Back 17

Capable of being extended or shaped by the blows of a hammer.

Front 18

Nonmetals

Back 18

The elements that do not have the characteristics of metals. Some of the nonmetals are gases at room temperature and pressure, some are solids, and one is a liquid. Various colors and textures occur among the nonmetals.

Front 19

Metalloids / semimetals

Back 19

The elements that have some but not all of the characteristics
of metals.

Front 20

Representative elements / Main-group elements.

Back 20

The elements in groups 1, 2, and 13 through 18 (the “A” groups) on the periodic table.

Front 21

Transition metals

Back 21

The elements in groups 3 through 12 (the “B” groups) on the periodic table.

Front 22

Inner transition elements

Back 22

The 28 elements at the bottom of the periodic table.

Front 23

Periods

Back 23

The horizontal rows on the periodic table.

Front 24

Atom

Back 24

The smallest part of an element that retains the chemical characteristics of the element.

Front 25

Atomic mass unit (u or amu)

Back 25

Unit of measurement for the masses of particles; 1/12 the mass of a carbon atom that has 6 protons, 6 neutrons, and 6 electrons.

Front 26

Proton

Back 26

A positively charged particle found in the nucleus of an atom.

Front 27

Electron

Back 27

A negatively charged particle found outside the nucleus of an atom.

Front 28

Neutron

Back 28

An uncharged particle found in the nucleus of an atom.

Front 29

Nucleus

Back 29

The extremely small, positively charged core of the atom.

Front 30

Ion

Back 30

Any charged particle, whether positively or negatively charged.

Front 31

Cation

Back 31

An ion formed from an atom that has lost one or more electrons and thus has become positively charged.

Front 32

Anion

Back 32

An ion formed from an atom that has gained one or more electrons and thus has become negatively charged.

Front 33

Isotopes

Back 33

Atoms that have the same number of protons but different numbers of neutrons. They have the same atomic number but different mass numbers.

Front 34

Atomic Number

Back 34

The number of protons in an atom’s nucleus. It establishes the element’s identity.

Front 35

Mass number

Back 35

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

Front 36

Covalent bond

Back 36

A link between atoms that results from their sharing two electrons.

Front 37

Molecule

Back 37

An uncharged collection of atoms held together with covalent bonds.

Front 38

Space-filling model

Back 38

A way of representing a molecule to show a somewhat realistic image of the electron‐charge clouds that surround the molecule’s atoms.

Front 39

Ball-and-stick model

Back 39

A representation of a molecule that uses balls for atoms and
sticks for covalent bonds.

Front 40

Diatomic

Back 40

Composed of paired atoms. The diatomic elements are H2, N2, O2, F2, Cl2, Br2, and I2.

Front 41

Compound

Back 41

A substance that contains two or more elements, the atoms of these elements always combining in the same whole‐number ratio.

Front 42

Chemical formula

Back 42

A concise written description of the components of a chemical compound. It identifies the elements in the compound by their symbols and indicates the relative number of atoms of each element with subscripts.

Front 43

Pure substance

Back 43

A sample of matter that has constant composition. There are two types of pure substances, elements and compounds.

Front 44

Mixture

Back 44

A sample of matter that contains two or more pure substances and has variable composition.

Front 45

Chemical bond

Back 45

An attraction between atoms or ions in chemical compounds. Covalent bonds and ionic bonds are examples.

Front 46

Polar covalent bond

Back 46

A covalent bond in which electrons are shared unequally, leading to a partial negative charge on the atom that attracts the electrons more and to a partial positive charge on the other atom.

Front 47

Nonpolar covalent bond

Back 47

A covalent bond in which the difference in electron‐attracting ability of two atoms in a bond is negligible (or zero), so the atoms in the bond have no significant charges.

Front 48

Ionic bond

Back 48

The attraction between a cation and an anion.

Front 49

Molecular compound

Back 49

A compound composed of molecules. In such compounds, all of the bonds between atoms are covalent bonds.

Front 50

Ionic compound

Back 50

A compound that consists of ions held together by ionic bonds.

Front 51

Valence electrons

Back 51

The electrons that are most important in the formation of chemical bonds. The number of valence electrons for the atoms of an element is equal to the element’s A‐group number on the periodic table.

Front 52

Electron-dot symbol

Back 52

A representation of an atom that consists of its elemental symbol surrounded by dots representing its valence electrons.

Front 53

Lewis structure

Back 53

A representation of a molecule that consists of the elemental symbol for each atom in the molecule, lines to show covalent bonds, and pairs of dots to indicate lone pairs.

Front 54

Lone pair

Back 54

Two electrons that are not involved in the covalent bonds between atoms but are important for explaining the arrangement of atoms in molecules. They are represented by pairs of dots in Lewis structures.

Front 55

Hydrocarbons

Back 55

Compounds that contain only carbon and hydrogen.

Front 56

Organic chemistry

Back 56

The branch of chemistry that involves the study of carbon‐based compounds.

Front 57

Double bond

Back 57

A link between atoms that results from the sharing of four electrons. It can be viewed as two 2‐electron covalent bonds.

Front 58

Triple bond

Back 58

A link between atoms that results from the sharing of six electrons. It can be viewed as three 2‐electron covalent bonds.

Front 59

Alcohols

Back 59

Compounds that contain a hydrocarbon group with one or more ‐OH groups attached.

Front 60

Tetrahedral

Back 60

The molecular shape that keeps the negative charge of four electron groups as far apart as possible. This shape has angles of 109.5° between the atoms.

Front 61

Bond angle

Back 61

The angle formed by straight lines (representing bonds) connecting the nuclei of three adjacent atoms.

Front 62

Binary covalent compound

Back 62

A compound that consists of two nonmetallic elements.

Front 63

Monatomic anions

Back 63

Negatively charged particles, such as Cl−, O2−, and N3−, that
contain single atoms with a negative charge.

Front 64

Monatomic cations

Back 64

Positively charged particles, such as Na+, Ca2+, and Al3+, that contain single atoms with a positive charge.

Front 65

Polyatomic ion

Back 65

A charged collection of atoms held together by covalent bonds.

Front 66

Binary ionic compound

Back 66

An ionic compound whose formula contains one symbol for
a metal and one symbol for a nonmetal.

Front 67

Chemical reaction / chemical change

Back 67

The conversion of one or more pure substances into one or more different pure substances.

Front 68

Reactants

Back 68

The substances that change in a chemical reaction. Their formulas are on the left side of the arrow in a chemical equation.

Front 69

Products

Back 69

The substances that form in a chemical reaction. Their formulas are on the right side of the arrow in a chemical equation.

Front 70

Coefficients

Back 70

The numbers in front of chemical formulas in a balanced chemical equation.

Front 71

Solution

Back 71

A mixture whose particles are so evenly distributed that the relative concentrations of the components are the same throughout. Solutions can also be called homogeneous mixtures.

Front 72

Aqueous solution

Back 72

A solution in which water is the solvent.

Front 73

Solute

Back 73

The gas in a solution of a gas in a liquid. The solid in a solution of a solid in a
liquid. The minor component in other solutions.

Front 74

Solvent

Back 74

The liquid in a solution of a gas in a liquid. The liquid in a solution of a solid in a liquid. The major component in other solutions.

Front 75

Double-displacement reaction

Back 75

A chemical reaction that has the following form: AB+CD → AD+CB

Front 76

Precipitation reaction

Back 76

A reaction in which one of the products is insoluble in water and comes out of solution as a solid.

Front 77

Precipitate

Back 77

A solid that comes out of solution.

Front 78

Precipitation

Back 78

The process of forming a solid in a solution.

Front 79

Crystals

Back 79

Solid particles whose component atoms, ions, or molecules are arranged in an organized, repeating pattern.

Front 80

Complete ionic equation

Back 80

A chemical equation that describes the actual form for each substance in solution. For example, ionic compounds that are dissolved in water are described as separate ions.

Front 81

Spectator ions

Back 81

Ions that play a role in delivering other ions into solution to react but that do not actively participate in the reaction themselves.

Front 82

Complete equation / molecular equation

Back 82

A chemical equation that includes uncharged formulas for all of the reactants and products. The formulas include the spectator ions, if any.

Front 83

Net ionic equation

Back 83

A chemical equation for which the spectator ions have been eliminated, leaving only the substances actively involved in the reaction.

Front 84

Solubility

Back 84

The maximum amount of solute that can be dissolved in a given amount of solvent.

Front 85

Hydronium ion

Back 85

H3O+

Front 86

Arrhenius acid

Back 86

According to the Arrhenius theory, any substance that generates hydronium ions, H3O+, when added to water.

Front 87

Acidic solution

Back 87

A solution with a significant concentration of hydronium ions,
H3O+.

Front 88

Binary acid

Back 88

Substances that have the general formula of HX(aq), where X is one of the first four halogens: HF(aq), HCl(aq), HBr(aq), and HI(aq).

Front 89

Oxyacids (oxoacids)

Back 89

Molecular substances that have the general formula HaXbOc. In other words, they contain hydrogen, oxygen, and one other element represented by X; the a, b, and c represent subscripts.

Front 90

Monoprotic acid

Back 90

An acid that donates one hydrogen ion per molecule in a reaction.

Front 91

Polyprotic acid

Back 91

An acid that can donate more than one hydrogen ion per molecule in a reaction.

Front 92

Diprotic acid

Back 92

An acid that can donate two hydrogen ions per molecule in a reaction.

Front 93

Triprotic acid

Back 93

An acid that can donate three hydrogen ions per molecule in a reaction.

Front 94

Strong acid

Back 94

An acid that donates its H+ ions to water in a reaction that goes completely to products. Such a compound produces close to one H3O+ ion in solution for each acid molecule dissolved in water.

Front 95

Reversible reaction

Back 95

A reaction in which the reactants are constantly forming products and, at the same time, the products are reforming the reactants.

Front 96

Weak acid

Back 96

A substance that is incompletely ionized in water due to the reversibility of the reaction that forms hydronium ions, H3O+, in water. Weak acids yield significantly less than one H3O+ ion in solution for each acid molecule dissolved in water.

Front 97

Arrhenius base

Back 97

A substance that produces hydroxide ions, OH−, when added to water.

Front 98

Basic solution

Back 98

A solution with a significant concentration of hydroxide ions, OH−.

Front 99

Strong base

Back 99

A substance that generates at least one hydroxide ion in solution for every unit of substance added to water.

Front 100

Weak base

Back 100

A substance that produces fewer hydroxide ions in water solution than particles of the substance added.

Front 101

Neutralization reaction

Back 101

A chemical reaction between an acid and a base.

Front 102

Brønsted-Lowry acid-base reaction

Back 102

A chemical reaction in which a proton, H+, is transferred.

Front 103

Brønsted-Lowry Acid

Back 103

A substance that donates protons, H+, in a Brønsted‐Lowry acid‐base reaction.

Front 104

Brønsted-Lowry Base

Back 104

A substance that accepts protons, H+, in a Brønsted‐Lowry acid‐base reaction.

Front 105

Conjugate acid

Back 105

The molecule or ion that forms when one H+ ion is added to a molecule or ion.

Front 106

Conjugate base

Back 106

The molecule or ion that forms when one H+ ion is removed from a molecule or ion.

Front 107

Conjugate acid-base pair

Back 107

Two molecules or ions that differ by one H+ ion.

Front 108

Amphoteric substance

Back 108

A substance that can act as either a Brønsted‐Lowry acid or a Brønsted‐Lowry base, depending on the circumstances.

Front 109

Oxidation

Back 109

Any chemical change in which at least one element loses electrons, either completely or partially.

Front 110

Reduction

Back 110

Any chemical change in which at least one element gains electrons, either completely or partially.

Front 111

Oxidation-reduction / redox reactions

Back 111

The chemical reactions in which there is a complete or partial transfer of electrons, resulting in oxidation and reduction.

Front 112

Half-reactions

Back 112

Separateoxidationandreductionreactionequationsinwhichelectrons are shown as a reactant or product.

Front 113

Reducing agent

Back 113

A substance that loses electrons, making it possible for another substance to gain electrons and be reduced.

Front 114

Oxidizing agent

Back 114

A substance that gains electrons, making it possible for another substance to lose electrons and be oxidized.

Front 115

Oxidation number (oxidation state).

Back 115

A tool for keeping track of the flow of electrons in redox reactions.

Front 116

Combination / synthesis reaction

Back 116

The joining of two or more elements or compounds into one product.

Front 117

Decomposition reaction

Back 117

The conversion of one compound into two or more simpler substances.

Front 118

Combustion reaction

Back 118

Rapid oxidation accompanied by heat and usually light.

Front 119

Single-displacement reaction

Back 119

Chemical change in which atoms of one element displace (or replace) atoms of another element in a compound.

Front 120

Voltaic cell

Back 120

A system in which two half‐reactions for a redox reaction are separated, allowing the electrons transferred in the reaction to be passed between them through a wire.

Front 121

Battery

Back 121

A device that has two or more voltaic cells connected together. The term is
also used to describe any device that converts chemical energy into electrical energy
using redox reactions.

Front 122

Electrodes

Back 122

The electrical conductors placed in the half‐cells of a voltaic cell.

Front 123

Anode

Back 123

The electrode at which oxidation occurs in a voltaic cell. It is the source of
electrons and is the negative electrode.

Front 124

Cathode

Back 124

The electrode at which reduction occurs in a voltaic cell. It is the positive electrode.

Front 125

Salt bridge

Back 125

A device used to keep the charges in a voltaic cell balanced.

Front 126

Electrolyte

Back 126

The portion of a voltaic cell that allows ions to flow.

Front 127

Primary battery

Back 127

A battery that is not rechargeable.

Front 128

Secondary / Storage battery

Back 128

A rechargeable battery.

Front 129

Electrolysis

Back 129

The process by which a redox reaction is pushed in the nonspontaneous
direction or the process of applying an external voltage to a voltaic cell, causing electrons to move from what would normally be the cell’s cathode toward its anode.

Front 130

Energy

Back 130

The capacity to do work.

Front 131

Kinetic energy

Back 131

The capacity to do work due to the motion of an object.

Front 132

Law of Conservation of Energy

Back 132

Energy can neither be created nor destroyed, but it can be transferred from one system to another and changed from one form to another.

Front 133

Potential energy

Back 133

A retrievable, stored form of energy an object possesses by virtue of its position or state.

Front 134

Endergonic (endogonic) change

Back 134

Change that absorbs energy.

Front 135

Exergonic (exogonic) change

Back 135

Change that releases energy.

Front 136

Joule (J)

Back 136

The accepted internation unit for energy.

Front 137

calorie (lowercase c)

Back 137

A common energy unit. There are 4.184 joules per calorie (abbreviated cal).

Front 138

Calorie (uppercase C)

Back 138

The dietary calorie (abbreviated Cal). In fact, it is a
kilocalorie, the equivalent of 4184 joules.

Front 139

Internal kinetic energy

Back 139

The energy associated with the random motion of particles.

Front 140

Temperature

Back 140

A measure of the average internal kinetic energy of an object.

Front 141

Heat

Back 141

The energy transferred from a region of higher temperature to a region of lower temperature due to collisions between particles.

Front 142

Radiant energy / electromagnetic radiation

Back 142

Energy that can be described in terms
of either oscillating electric and magnetic fields or in terms of a stream of tiny
packets of energy with no mass.

Front 143

Photons

Back 143

Tiny packets or particles of radiant energy.

Front 144

Wavelength (λ - lambda)

Back 144

The distance in space over which a wave completes one cycle of its repeated form.

Front 145

Exothermic change

Back 145

Change that leads to heat energy being released from the system to the surroundings.

Front 146

Endothermic change

Back 146

Change that leads the system to absorb heat energy from the surroundings.

Front 147

Troposphere

Back 147

The lowest layer of the earth's atmosphere. It extends from the surface of the earth to about 10 km above the earth.

Front 148

Stratosphere

Back 148

The second layer of the earth’s atmosphere, which extends from about
10 km to about 50 km above sea level.

Front 149

UV-A

Back 149

Ultraviolet radiation in the range of about 320 to 400 nm wavelengths. This is
the part of the ultraviolet spectrum that reaches the earth and provides energy for
the production of vitamin D.

Front 150

UV-B

Back 150

Ultraviolet radiation in the range of about 290 to 320 nm wavelengths. Most
of this radiation is filtered out by the earth’s atmosphere, but some reaches the surface of the earth. Excessive exposure can cause sunburn, premature skin aging, and skin cancer.

Front 151

UV-C

Back 151

Ultraviolet radiation in the range of about 40 to 290 nm wavelengths. Almost all UV‐C is filtered out by our atmosphere. Because DNA and proteins absorb radiation in this range, UV‐C could cause crop damage and general ecological disaster if it were to reach the earth’s surface in significant quantities.

Front 152

Catalyst

Back 152

A substance that speeds a chemical reaction without being permanently altered itself.

Front 153

Chloroflourocarbon (CFC)

Back 153

A compound composed of just carbon, chlorine, and fluorine.