CHEMISTRY: Intro. to Chemistry & Matter

Introduction to Chemistry &
Classification of Matter

Chemistry - the study of the composition and structure of materials, and the changes they undergo


Branches of Chemistry

organic the study of carbon-containing compounds

inorganic the study of all substances not classified as organic

physical the study of properties and changes involving matter and energy

analytical the identification of components and composition of materials

biochemistry the study of substances and processes occurring in living things

theoretical the use of mathematics to predict the properties of new compounds

Research
Basic research for the sake of increasing knowledge; knowledge for the sake of knowledge
Applied research carried out to solve a specific problem

Definitions:
Matter anything that has the property of inertia

Inertia a property of matter that shows itself as a resistance to any change in motion

Mass the amount of matter an object possesses

Weight the gravitational force of attraction of the earth (or other celestial body) for an object

Atom the smallest unit of an element that maintains the properties of that element

Element a pure substance consisting of only one type of atom

Compound a pure substance consisting of more than one type of atom

Extensive Properties Properties of a substance that depend on the amount of material present (mass, volume)

Intensive Properties Properties of a substance that are independent of the amount of material (color, density, m.p.)

Physical Property A characteristic that can be observed without changing the identity of the substance (melting point, boiling point, specific gravity, solubility)

Physical Change A change in a substance that does not involve changing the identity of the substance (melting, boiling, dissolution)

Chemical Property Refers to a substance's ability to undergo a change that transforms it into a different substance (reacts with acid to produce hydrogen, flammable)

Chemical Change A change in which one or more substances are converted into different substances (combustion)

Solid matter has definite shape and definite volume

Liquid matter had definite volume but takes the shape of its container

Gas matter has neither a definite volume nor a definite shape

Classification of Matter

Matter anything that has mass and occupies space

Mixture a blend of two or more kinds of matter with each component retaining its own identity

Phase any part of a system that has uniform composition and properties

Heterogeneous a mixture in which the components can be separated by physical means (e.g., filtration)

Homogeneous a mixture in which the components cannot be separated by physical means - the mixture is totally
uniform in composition

Substance matter that has a fixed composition (oxygen, table salt, sugar); element or compound

Element a pure substance consisting of only one type of atom

Compound a pure substance consisting of more than one type of atom

Classification of Elements

Metal An element that is a good conductor of heat and electricity;likes to donate electrons (aluminum, copper, magnesium)

Nonmetal An element that is a poor conductor of heat and electricity;likes to accept electrons (fluorine, nitrogen, phosphorus)

Metalloid Element possessing the properties of both metals and nonmetals (silicon, arsenic, antimony)

Noble Gases The elements of Group 18; are generally unreactive; (helium, argon, krypton)



The Periodic Table

Group/Family Vertical column of elements
Period Horizontal row of elements


Energy

Law of Conservation of Mass Mass is neither created nor destroyed during normal physical or chemical changes

Law of Conservation of Energy Energy is neither created nor destroyed during normal physical or chemical changes

Law of Conservation of Matter and Energy The sum of matter and energy is neither created nor destroyed

Energy a property of matter of which there are two types:

Kinetic Energy (KE) Energy of motion: KE = 1/2 mv2

Potential Energy (PE) Energy of position: PE = mgh