Introduction to Chemistry. Matter: Anything that has mass and volume States of Matter.
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Transcript of Introduction to Chemistry. Matter: Anything that has mass and volume States of Matter.
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)