Chemistry Chapter 1 Notes 1: Introduction To Matter And Measurement

Front 1

Matter

Back 1

anything that takes up space and has mass

Front 2

Chemistry

Back 2

a science that studies the composition and properties of matter, and the changes that matter undergoes.

Front 3

Atoms

Back 3

the smallest distinctive units in a sample of matter

Front 4

Molecules

Back 4

larger units in which two or more atoms are joined together

Front 5

Gas (Vapor)

Back 5

matter that has no fixed volume or shape (conforms to the container)- can be compressed to fit a much smaller volume- can expand to fill larger volume. The particles of a gas are FAR apart and moving at high speeds- colliding with each other- and walls of container

Front 6

Liquid

Back 6

matter that has a distinct volume independent of its container but has NO specific shape- will assume the shape of the container and cannot be compressed appreciably. particles are not as far apart as in gas phase- still move rapidly- allowing them to slide, glide, and rotate past and over each other- will "pour"

Front 7

Solid

Back 7

matter that is rigid and cannot be compressed to an appreciable extent- the atoms and molecules are held tightly together, usually in definite arrangements- in which the molecules can wiggle and vibrate only slightly in otherwise fixed positions.

Front 8

Kinetic Energy

Back 8

the energy associated with an object by virtue of its motion. An object of mass m and speed or velocity v has a kinetic energy Ek equal to: Ek= (1/2) mv^2

Front 9

Intramolecular Forces

Back 9

forces within a molecule- electrostatic attractions that produce chemical bonds between atoms (ionic and covalent)

Front 10

Intermolecular Forces

Back 10

electrostatic attractions between molecules

Front 11

Kinetic Molecular Theory

Back 11

all matter is in constant motion and as it is heated, the particles move faster, and as the particles are cooled, they move slower

Front 12

Matter can be classified into two main categories of 1)_________ ________ and 2)_________

Back 12

1) Pure Substances
2) Mixtures

Front 13

Pure Substances

Back 13

matter that has a fixed composition and distinct properties (either elements or compounds) (have constant boiling points-- mixtures do not!)

Front 14

Elements

Back 14

matter that cannot be broken down into other simple substances by chemical reaction or decomposition. Each element is composed of its own kind of atom identified by their symbols
ex. Carbon- C, Mercury- Hg

Front 15

Compounds

Back 15

a substance made up of atoms of two or more elements, with the different kinds of atoms combined in fixed proportions by mass. Compounds CAN be broken down into elements by chemical reactions. (properties of compounds are different from those of the elements they contain)
ex. NaCl, H20

Front 16

Mixtures

Back 16

(comprise most of the matter we encounter!) Matter that has no fixed composition and are combinations of two or more pure substances in which each pure substance maintains its own chemical identity and therefore, properties
(the substances making up a mixture are called components of the mixture- these can be separated)

Front 17

Homogeneous Mixture

Back 17

a mixture that has the same composition and properties throughout-- also known as a SOLUTION
ex. air, thoroughly dissolved salt in a glass of water

Front 18

Heterogeneous Mixture

Back 18

a mixture that varies in composition and/or properties from one part of the mixture to another
ex. sand in a bucket, cement

Front 19

Law of Definite Proportions (or Law of Definite Composition)

Back 19

states that the elemental composition (or ratio by atomic mass) of a pure compound is always the same.
ex. H202= 2(1): 2(8) = 2:16 = 1:8

Front 20

Law of Multiple Proportions

Back 20

states the fact that it IS possible for two or more compounds, with different ratios by mass of the same elements, to be made
ex. CuO and Cu2O

Front 21

Separation of Mixtures

Back 21

since each component of a mixture retains its own properties, we can separate a mixture by taking advantage of their different properties
ex. filtration, by color, reactivity, boiling points, etc.

Front 22

Physical Properties

Back 22

characteristics displayed by a sample of matter without undergoing any change in its composition
ex. odor, color, density, boiling point, etc.

Front 23

Chemical Properties

Back 23

characteristics displayed by a sample of matter as it undergoes a change in its chemical composition- they describe the way a substance may change or react to form other substances
ex. combustibility, reactability with acids

Front 24

Intensive Properties

Back 24

do NOT depend on the amount of the sample
ex. temperature, density, melting point

Front 25

Extensive Properties

Back 25

DO depend on the quantity/amount of the sample
ex. measurements of volume and mass

Front 26

Physical Changes

Back 26

when a sample of matter undergoes a noticeable change at the macroscopic level, but has NO change in composition.
~ALL PHASE CHANGES

Front 27

Chemical Changes

Back 27

(also chemical reaction) a sample of matter undergoes a change in composition and/or the structure of its molecules
ex. cooking foods, combustion of ethyl alcohol