Chem: Ch 2

Front 1

Element

Back 1

A substance that cannot be separated into simpler substances by physical or chemical means.

Front 2

Compound

Back 2

A substance composed of two or more elements that are chemically united in fixed proportions. Can be separated by chemical means, not physical means.

Front 3

Mixture

Back 3

Matter composed of a physical intermingling of two or more substances and whose composition is variable (unlike a compound), and can be separated by physical means.

Front 4

Heterogeneous Mixtures

Back 4

Mixtures that do not have a uniform composition (e.g., raisin bran).

Front 5

Homogeneous Mixtures

Back 5

Mixtures whose composition is uniform right down to the submicroscopic level (e.g., salt water).

Front 6

Solution

Back 6

Another term for homogeneous mixture.

Front 7

Aqueous solution

Back 7

A solution whose major component is water.

Front 8

Law of Mass Conservation

Back 8

Law that states that the total mass of substances does not change during a chemical reaction.

Front 9

Definite Composition

Back 9

That no matter what its source, a particular chemical compound is composed of the same elements in the same fractions by mass.

Front 10

Relative mass

Back 10

What different samples of the same compound contain of each element.

Front 11

Law of Definite Composition provides

Back 11

better evidence that the world is composed of smaller objects than mass conservation does (that the total mass of substances does not change during a chemical reaction).

Front 12

Law of Multiple Proportions

Back 12

States that different compounds that happen to consist of the same elements show a mass relationship.

Front 13

Problems solved with Law of Multiple Proportions

Back 13

Have to make the thing I'm not comparing to have equal amounts of each other, then I can compare what I'm comparing.

Front 14

Dalton's Atomic Theory

Back 14

Dalton proposes that:
- All matter consists of atoms that cannot be destroyed (we can destroy them now).
- Atoms of one element cannot be converted into atoms of another element (can actually be converted by nuclear means).
- Atoms of an element are (almost) identical in mass and other properties.

Front 15

Electrons

Back 15

Negatively charged particles.

Front 16

Charge-to-mass-ratio for electrons

Back 16

-1.759 x 10^8C /g
A lot of charge per gram.

Front 17

Charge of a single electron

Back 17

-1.602 x 10^-19 C

Front 18

Mass of an electron

Back 18

9.107 x 10^-28 g

Front 19

Nucleus

Back 19

A small central region in which all of the positive charge and most of the mass of an atom is concentrated within.

Front 20

Proton

Back 20

The particle that contains the positive charge in a nucleus.

Front 21

Neutron

Back 21

A massive but uncharged particle in the nucleus.

Front 22

Charge of an electron or proton

Back 22

-1, +1

Front 23

Isotopes

Back 23

Atoms that have the same number of protons but different numbers of neutrons

Front 24

Most of the mass of an atom is from the

Back 24

protons and neutrons in the nucleus.

Front 25

Period

Back 25

The elements in a row of the periodic table.

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Family or Group

Back 26

The elements in a column on the periodic table.

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Ionic Bonding

Back 27

When one atom transfers electrons to another atom and the particles "stick together."

Front 28

Covalent Bonding

Back 28

When atoms share electrons and thus stay in the vicinity of one another. Usually occurs between two nonmetals.

Front 29

Cations

Back 29

THe atoms which lose electrons, which become positively charged.

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Anions

Back 30

The atoms which gain electrons which become negatively charged.

Front 31

Compounds are electrically

Back 31

neutral.

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Molecule

Back 32

A cluster of covalently bonded atoms.

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Polyatomic ions

Back 33

A group of atoms that are covalently bonded that gains or loses electrons and obtains a charge. (Not compounds.)

Front 34

Molecular formula

Back 34

A formula that expresses the actual composition of each molecule and how many atoms of each element are present.

Front 35

Empirical formula

Back 35

A formula that expresses the relative numbers of atoms in each element, but not necessarily the actual amount of atoms.

Front 36

Formula unit

Back 36

A concept that allows us to think about ionic compounds in terms like those used for molecular compounds.

Front 37

Structural formulas

Back 37

Formulas that do specify the order and structure in which atoms are bonded in the molecules. More informative than chemical formulas, but lack information about spatial layout.

Front 38

Perspective drawings and ball-and-stick models

Back 38

Both provide 3-dimensional depictions of molecules, though aren't accurate representations of what molecules would "look like."

Front 39

Space-filling model

Back 39

Depictions that show the geometry, the extent of overlap, and relative sizes of the molecule.

Front 40

Electron density

Back 40

Informative representation that uses a ball-and-stick figure and uses a color-coded space-filling figure to illustrate the distribution of charge around the atoms.

Front 41

Oxoanions

Back 41

Polyatomic anions that contain one or more oxygen atoms.

Front 42

Ammonium

Back 42

NH4+

Front 43

Chlorate

Back 43

ClO3-

Front 44

Nitrate

Back 44

NO3-

Front 45

Carbonate

Back 45

CO3 2-

Front 46

Phosphate

Back 46

PO4 3-

Front 47

Hydrates

Back 47

Ionic compounds that have water molecules embedded within them.

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Acid

Back 48

A substance that yields hydrogen ions (H+ or H3O+) when dissolved in water.

Front 49

Base

Back 49

A substance that yields hydroxide ions (OH-) when dissolved in water.

Front 50

NH3

Back 50

Ammonia

Front 51

PH3

Back 51

Phosphine

Front 52

CH4

Back 52

Methane

Front 53

SiH4

Back 53

Silane

Front 54

B2H6

Back 54

Diborane