ChemistryChemistry

Matter and Matter and ChangeChange

Chemistry is…

…the study of the composition, structure, and properties of matter and the changes it undergoes

C2H5OH + 3 O2 2 CO2 + 3 H2O + Energy

Reactants Products

MatteMatterr

Anything that has mass and occupies space

MasMasssA measure of the amount of matter

AtomAtomThe smallest unit of an element that maintainsthe properties of that elementElementElement

A pure substance made of only one kind of atom

CompouCompoundnd

A substance that is made from the atoms of two or more elements that are chemically bonded.

Sucrose – C12H22O11

Sucrose is also known as table sugar, and is used to make Gummy Bears!

Properties of Properties of MatterMatterExtensive propertiesExtensive properties

Intensive propertiesIntensive properties

Volume

MassEnergy Content (think Calories!)

depend on the amount of matter that is present.

do not depend on the amount of matter present.

Melting point

Boiling point

Density

Physical Physical ChangeChangeA change in a substance that does not involve a change in the identity of the substance.

Example:

Phase Changes

Phase Phase DifferencesDifferences

SolidSolid – definite volume and shape; particles packed in fixed positions.LiquidLiquid – definite volume but indefinite shape; particles close together but not in fixed positionsGasGas – neither definite volume nor definite shape; particles are at great distances from one anotherPlasma – high temperature, ionized phase of matter as found on the sun.

Three PhasesThree Phases

Copper Phases - SolidCopper Phases - Solid

Copper Phases - LiquidCopper Phases - Liquid

Copper Phases – Vapor (gas)Copper Phases – Vapor (gas)

Chemical Chemical ChangeChangeA change in which one or more substances are converted into different substances.

Heat and light are often evidence of a chemical change.

Classification of Matter

Separation of a MixtureSeparation of a Mixture

The constituents of the mixture retain The constituents of the mixture retain their identity and may be separated by their identity and may be separated by physical means.physical means.

Separation of a MixtureSeparation of a Mixture

The components of dyes such as ink may be separated by paper chromatography.

Separation of a MixtureSeparation of a Mixture

Distillation

Separation of a CompoundSeparation of a CompoundThe Electrolysis of water

Water Hydrogen + Oxygen

H2O H2 + O2

Reactant Products

Compounds must be separated by chemical means.

With the application of electricity, water can be separated into its elements

The Periodic TableThe Periodic Table

Period

Group or family

PeriodGroup or Family

Properties of MetalsProperties of Metals Metals are good conductors of heat and electricity

Metals are malleable

Metals are ductile

Metals have high tensile strength

Metals have luster

Examples of MetalsExamples of Metals

Potassium, K reacts with water and must be stored in kerosene

Zinc, Zn, is more stable than potassium

Copper, Cu, is a relatively soft metal, and a very good electrical conductor.

Mercury, Hg, is the only metal that exists as a liquid at room temperature

PropertiesProperties of Nonmetalsof Nonmetals

Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element. Nonmetals are poor conductors of heat and electricity Nonmetals tend to be brittle Many nonmetals are gases at room temperature

Examples of NonmetalsExamples of Nonmetals

Sulfur, S, was once known as “brimstone”

Microspheres of phosphorus, P, a reactive nonmetal

Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure

Properties of MetalloidsProperties of Metalloids

Metalloids straddle the border between metals and nonmetals on the periodic table.

They have properties of both metals and nonmetals.Metalloids are more brittle than metals, less brittle than most nonmetallic solids Metalloids are semiconductors of electricity Some metalloids possess metallic luster

Silicon, Si – A MetalloidSilicon, Si – A Metalloid

Silicon has metallic luster Silicon is brittle like a nonmetal Silicon is a semiconductor of electricity

Other metalloids include:

Boron, B Germanium, Ge Arsenic, As Antimony, Sb Tellurium, Te