1. 2 matter defined 3 matter can be invisible. matter appears to be continuous and unbroken. matter...

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Matter DefinedMatter Defined

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• Matter can be invisible.

• Matter appears to be continuous and unbroken.

• Matter is anything that has mass and occupies space.

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Physical States of Physical States of MatterMatter

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Physical Properties of Solids, Liquids, and Gases

State Shape Volume Particles Compressibility

Solid Definite Definite Tightly packed Very Slight

Liquid Indefinite Definite Mobile; Cohering Slight

Gas Indefinite Indefinite Independent High

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Substances and Substances and MixturesMixtures

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Matter refers to all of the materials that make up the universe.

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Substance

A particular kind of matter that has a fixed composition and distinct properties.

Examples

ammonia, water, and oxygen.

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Homogeneous Matter

Matter that is uniform in appearance and with uniform properties throughout.

Examples

ice, soda, solid gold

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Heterogeneous Matter

Matter with two or more physically distinct phases present.

Examples

wood, blood

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Phase

A homogenous part of a system separated from other parts by physical boundaries.

Examples

In an ice water mixture ice is the solid phase and water is the liquid phase

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Mixture

Matter containing 2 or more substances that are present in variable amounts. Mixtures are variable in composition. They can be homogeneous or heterogeneous.

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Homogeneous Mixture (Solution)A homogeneous mixture of 2 or more substances. It has one phase.

ExampleSugar and water. Before the sugar and water are mixed each is a separate phase. After mixing the sugar is evenly dispersed throughout the volume of the water.

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Example

Sugar and fine white sand. The amount of sugar relative to sand can be varied. The sugar and sand each retain their own properties.

Heterogeneous MixtureA heterogeneous mixture consists of 2 or more phases.

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Classification of matter: A pure substance is always homogeneous in composition, whereas a mixture always contains two or more substances and may be either homogeneous or heterogeneous.

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ElementsElements

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An element is a fundamental or elementary substance that cannot be broken down into simpler substances by chemical means

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• All known substances on Earth and probably the universe are formed by combinations of more than 100 elements.

• Each element has a number.– Beginning with hydrogen as 1 the

elements are numbered in order of increasing complexity.

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• Most substances can be decomposed into two or more simpler substances.– Water can be decomposed into hydrogen

and oxygen.

– Table salt can be decomposed into sodium and chlorine.

• An element cannot be decomposed into a simpler substance.

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ATOM

• The smallest particle of an element that can exist.

• The smallest unit of an element that can enter into a chemical reaction.

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Distribution of Distribution of ElementsElements

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• Elements are not distributed equally by nature.– Oxygen is the most abundant element in

the human body (65%).

– Oxygen is the most abundant element in the crust of the earth (49.2%)..

• In the universe the most abundant element is hydrogen (91%) and the second most abundant element is helium (8.75%).

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Distribution of the common elements in nature.

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Names of theNames of theElementsElements

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Sources of Element Names

Famous-Scientist

• Einsteinium: named for Albert Einstein.

Location• Germanium: discovered in 1866 by a German chemist.

German-Color

• Bismuth: from the German weisse mass meaning white mass.

Greek-Color

• Iodine: from the Greek iodes meaning violet.

Latin-Property

• Fluorine: from the Latin fluere meaning to flow.

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Symbols of the Symbols of the ElementsElements

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• A symbol stands for– the element itself

– one atom of the element

– a particular quantity of the element

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Ne neon

Rules governing symbols of the elements are:

1. Symbols have either one or two letters.

2. If one letter is used it is capitalized.

3. If two letters are used, only the first is capitalized.

H hydrogenC carbon

Ba barium

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50 Common Elements and Their Symbols

Al aluminum Cr chromium Li lithium Rn radon

Sb antimony Co cobalt Mg magnesium Rb rubidium

Ar argon Cu copper Mn manganese Se selenium

As arsenic F fluorine Hg mercury Si silicon

Ba barium Ga gallium Ne neon Ag silver

Be beryllium Ge germanium Ni nickel Na sodium

B boron Au gold N nitrogen Sr strontium

Br bromine He helium O oxygen S sulfur

Ca calcium H hydrogen P phosphorus Sn tin

C carbon I iodine Pt platinum W tungsten

Cs cesium Fe iron K potassium U uranium

Cl chlorine Kr krypton Ra radium Xe xenon

Pb lead Zn zinc

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Metals, Nonmetals Metals, Nonmetals and Metalloidsand Metalloids

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MetalsMetals

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Most elements

are metals

• Metals are solid at room temperature.– Mercury is an exception. At room temperature it

is a liquid.

• Metals have high luster (they are shiny).

• Metals are good conductors of heat and electricity.

• Metals are malleable (they can be rolled or hammered into sheets).

physicalproperties of metals

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• Metals are ductile (they can be drawn into wires).

• Most metals have a high melting point.

• Metals have high densities

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NonmetalsNonmetals

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• Have relatively low melting points

• Have low densities.

• Poor conductors of heat and electricity

• At room temperature carbon, phosphorous, sulfur, selenium, and iodine are solids.

Physical Properties of Nonmetals

• Lack luster (they are dull)

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MetalloidsMetalloids

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Metalloids have properties that are intermediate between metals and nonmetals

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The Metalloids

1. boron

2. silicon

3. germanium

4. arsenic

5. antimony

6. tellurium

7. polonium

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Metals are found to the left of the metalloidsNonmetals are found to the right of the metalloids.

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CompoundsCompounds

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A compound is a distinct substance that contains two or more elements combined in a definite proportion by weight.

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There are two types of compounds: molecular and ionic.

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MoleculesMolecules

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A molecule is the smallest uncharged individual unit of a compound formed by the union of two or more atoms.

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• A water molecule consists of two hydrogen atoms and one oxygen atom.

• If it is subdivided the water molecule will be destroyed and hydrogen and oxygen will be formed.

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Ionic CompoundsIonic Compounds

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An ion is a positively or negatively charged atom or group of atoms.

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A cation is a positively charged ion.

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An anion is a negatively charged ion.

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Ionic compounds are held together by attractive forces between positively and negatively charged ions.

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Ionic Compound FormulasIonic Compound Formulas

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Sodium chloride and other ionic compounds consist of large aggregates of cations and anions.

The actual chemical formulas of ionic compounds express the smallest whole number ratio that exists between these cations and the anions.

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• The formula NaCl does not mean that a molecule of NaCl exists.

• The formula NaCl means that the ratio of sodium to chlorine in a sodium chloride crystal is one to one.

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The ratio of Na+ to Cl- is 1:1

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Compounds can be classified as molecular or ionic. Ionic compounds are held together by attractive forces between their positive and negative charges. Molecular compounds are held together by covalent bonds.

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Elements That Exist as Elements That Exist as Diatomic MoleculesDiatomic Molecules

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A diatomic molecule contains exactly two atoms of the same or different elements.

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Chemical FormulasChemical Formulas

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chemicalformulas

Show the symbols of the atoms of the elements present in a compound.

CaCl2Ca calciumCl chlorine

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chemicalformulas

Show the ratio of the atoms of the elements present in a compound.

2 Cl1 Ca

CaCl2

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Rules for Writing Chemical FormulasRules for Writing

Chemical Formulas

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When a formula contains one atom of an element the symbol of that element represents the one atom. The number one (1) is not used as a subscript.

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NaCl

indicatesthe element sodium(one atom)

indicatesthe element chlorine(one atom)

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When the formula contains more than one atoms of an element the number of atoms is indicated by a subscript written to the right of the symbol of that atom.

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indicates 3 H atoms

indicatesthe element phosphorous (P)

indicatesthe element hydrogen (H)

indicatesthe element oxygen (O)H3PO4

indicates 4 O atoms

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When the formula contains more than one of a group of atoms that occurs as a unit, parentheses are placed around the group, and the number of units of the group is indicated by a subscript placed to the right of the parentheses.

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Ba3(PO4)2

indicates three Ba atoms

3-4phosphate (PO )

indicates two

groups

indicatesthe element barium

indicates the phosphate groupcomposed of one phosphorous atom and four oxygen atoms

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Formulas written as H2O, H2SO4, Ca(NO3)2 and C12H22O11

show only the number and kind of each atom contained in the compound; they do not show the arrangements of the atoms in the compound or how they are chemically bonded to each other.

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