Introduction to Chemistry

Matter: Anything that has mass and volume

States of Matter

Physical propertiesPhysical propertiesProperties that do not change the Properties that do not change the

chemical nature of matterchemical nature of matter

•Boiling point•Melting point•Freezing point•Color•Density

Chemical PropertiesChemical PropertiesProperties that do change the chemical nature of Properties that do change the chemical nature of

mattermatter OxidationOxidation Rusting of iron = Rusting of iron =

Iron Oxide (FeOIron Oxide (FeO22))

pHpH

FlammabilityFlammability Frying an eggFrying an egg

Physical & Chemical Changes

All Matter is composed of :

Atoms – Means “unable to be Atoms – Means “unable to be cut”cut”

The smallest particle of an The smallest particle of an element that still has the element that still has the characteristics of that characteristics of that elementelement

Elements Substances that can’t be broken Substances that can’t be broken

down into simpler substancesdown into simpler substances

96% of human mass is made up of C, H, O, N

Periodic Table of The Elements

Atoms are made up of smaller subatomic particles

Protons: positively charged (Located in the nucleus)Protons: positively charged (Located in the nucleus) Neutrons: neutrally charged (Located in the Neutrons: neutrally charged (Located in the

nucleus)nucleus) Electrons: negatively charged (Located around the Electrons: negatively charged (Located around the

nucleus)nucleus)

Discovered by Ernest Rutherford in 1919 Discovered by

J.J. Thomson in 1897

Discovered by James Chadwick in 1932

Each atom has the same number of protons and electrons

Electrons have less mass than protons. 1 proton= 1870 electrons

Electrons located farther away from the nucleus have more energy

Atomic number = number of protons

Atomic mass = number of protons & neutrons

Electron # = Proton # in Neutral elements

He2

4.003Atomic number:Atomic mass:

# of Protons

# of Electrons

# of Neutrons

Isotopes

Neutron #’s change

Hydrogen: H1

1

Deuterium: H1

2

Tritium H1

3

When elements combine to form When elements combine to form substances with two or more atoms…substances with two or more atoms…

Compounds are formed

Mixtures

When one or more atoms are physically combined but NOT chemically combined (Individual atoms retain their own properties)

Easily separated by non-chemical means

Solutions

Solute – Substance dissolvedSolute – Substance dissolved

Solvent – Dissolves substances Solvent – Dissolves substances

(Water is the universal solvent)(Water is the universal solvent)

Colloids – light does not penetrateColloids – light does not penetrate

SuspensionsSuspensions

Solubility of Solutions

The amount of solute a solvent can The amount of solute a solvent can dissolvedissolve

Solubility affected by:Solubility affected by:TemperatureTemperatureConcentrationConcentration

Ions

Ions are charged particles.

Atoms have either lost or gained one or more electrons

Ionic bondCation Anion

Covalent BondOccurs when atoms SHARE electrons

Diatomic molecule

Special Note

Molecules are only formed with covalent bonds

Molecules

A group of atoms held A group of atoms held together bytogether by covalentcovalent bondsbonds

Water, hydrogen gas, oxygen, carbon Water, hydrogen gas, oxygen, carbon dioxidedioxide

Uneven distribution of electrons results in a polar molecule

Hydrogen BondA bond formed in polar molecules

Cohesion & Adhesion: Due to Hydrogen Bonding

Cohesion – The ability of hydrogen bonds to attract like molecules

Adhesion – The ability of hydrogen bonds to attract different types of molecules

Why can these animals walk on water?

Capillary Action isDue to Adhesion

Acids & Bases

Acids are formed by hydrogen cations

Bases are formed by hydroxide anions

Acids

Donate protons (Hydrogen Ions) to water to Donate protons (Hydrogen Ions) to water to form hydronium ionsform hydronium ions

pH 0-6.99 pH 0-6.99

Taste SourTaste Sour

Turn litmus paper red Turn litmus paper red

Strong acidsStrong acids completely dissociate to form ions completely dissociate to form ions

Bases Donate hydroxideDonate hydroxide pH 7.01-14pH 7.01-14 Accept protonsAccept protons Taste bitter Taste bitter

Feel slimyFeel slimy Turn litmus paper blueTurn litmus paper blue Strong bases completely dissociate to form ionsStrong bases completely dissociate to form ions

pHpH

Buffers

Compounds that tend to neutralize Compounds that tend to neutralize the pH of a solution by combining the pH of a solution by combining with with eithereither H+ ions or OH- ions to H+ ions or OH- ions to keep the solution neutralkeep the solution neutral

Chemical Reactions Synthesis (A+BSynthesis (A+BC)C) Decomposition (CDecomposition (CA+B)A+B) Single Replacement (AB+CSingle Replacement (AB+C AC+B) AC+B) Double Replacement (AB+CDDouble Replacement (AB+CDAC+BD)AC+BD)

Reactants are to the left of the arrow (Elements Reactants are to the left of the arrow (Elements reacting)reacting)

Products are to the right of the arrow (Stuff made)Products are to the right of the arrow (Stuff made)

Subscripts CANNOT be changedSubscripts CANNOT be changed Coefficients can be changed to balance an equation)Coefficients can be changed to balance an equation)

Chemical Reactions

Endothermic rxn’s absorb heatEndothermic rxn’s absorb heat Exothermic rxn’s give off heatExothermic rxn’s give off heat

Organic Chemistry Organic molecules are any molecules that contain Organic molecules are any molecules that contain

atoms from three elements: carbon, hydrogen, and atoms from three elements: carbon, hydrogen, and oxygen. oxygen.

For example, glucose is organic, since its molecular For example, glucose is organic, since its molecular formula is Cformula is C66HH1212OO66

Carbon dioxide (COCarbon dioxide (CO22) is inorganic since it does not ) is inorganic since it does not

contain hydrogen. contain hydrogen.

All organic molecules have two parts: The carbon backbone & the functional group

Carbon atoms can form single, double, or triple bonds

4 Groups of Organic Compounds Found 4 Groups of Organic Compounds Found in Living Thingsin Living Things

Carbohydrates (C-H-O 1:2:1 ratio)Carbohydrates (C-H-O 1:2:1 ratio)

Lipids (C-H-O)Lipids (C-H-O)

Proteins (C-H-O-N)…sometimes SProteins (C-H-O-N)…sometimes S

Nucleic Acids (C-H-O-N-P)Nucleic Acids (C-H-O-N-P)