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EOC & CHEMISTRY BIG IDEAS Review

EOC & CHEMISTRY BIG IDEAS Review. Semester 2 EOC May 30, 2014. Mr. Rosato’s Physical Science. Scientific Method Steps 1-3. Predict. Observe. Think. Scientific Method Steps 4-6. Classify. Compare & Contrast. Infer. States of Matter. Plasma Highest Energy Atoms not stuck

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EOC & CHEMISTRY BIG IDEAS Review

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  1. EOC & CHEMISTRY BIG IDEAS Review Semester 2 EOC May 30, 2014 Mr. Rosato’s Physical Science

  2. Scientific Method Steps 1-3 Predict Observe Think

  3. Scientific Method Steps 4-6 Classify Compare & Contrast Infer

  4. States of Matter Plasma Highest Energy Atoms not stuck together Gas High Energy Atoms not stuck together Ionization Relaxation Evaporation Condensation Boiling Point Dew Point Liquid Medium Energy Atoms loosely stuck together _Melting Point Melting Solid Low Energy Atoms tightly stuck together Freezing Point Freezing

  5. States of Matter: Big Ideas • Plasma- freely moving molecules, free electrons • Gas-freely moving molecules • Liquid-loosely packed • Solid- tightly packed

  6. MATTER Made of Atoms Has Mass & takes up Space Mixtures Made of more than one type of matter Pure Substances Made of one type of matter Atom + Atom = Molecule Molecule+Molecule = Element Heterogeneous Made of more than one phase Can be separated Homogeneous one phase Elements Made of one type of atom Compounds Made of 2 or More atoms bonded together Examples: Trail Mix Salad Solution All its regions are Identical Ex: Kool-Aid Atom + Atom = Molecule Solute The stuff that is dissolved In the liquid Ex: Kool-Aid mix Solvent The liquid that forms the solution Ex: Water Molecule + Molecule = Compound

  7. Properties of Matter States Solid Liquid Gas Plasma Chemical Properties Describe how it can form a new substance Physical Properties Describe a Substance Signs of Chemical Reaction Color Change Temp change Bubbles Solid Formation Odor Properties Flammability Reactivity Toxicity Changes of State Melting Freezing Boiling Condensation Ionization Relaxation Characteristics Color Shape Size Texture Mass Volume Density

  8. Matter BIG IDEAS ATOMS =Building Blocks of Matter MOLECULE = 2 or more atoms bonded together. Ex: NaCl, H2O, CH4, H2 • Pure Substances • Elements: one type of Atom (Ex: Al Foil) • Compounds: 2 or more atoms bonded together (Ex: H2O) • Mixtures • more than one type of matter • States • Solid • Liquid • Gas • Plasma • Physical Properties • Describe a substance ( color size, shape) • Chemical Properties • Describe how it can make a new substance (flammable) • Signs of Chemical Reaction • Color Change • Temp change • Bubbles • Solid Formation • Odor

  9. Atomic Structure Atomic # Proton# Electron# SAME

  10. Bohr Model of the Atom • Electrons are arranged in fixed orbits around the nucleus. • fill up orbits in order from lowest energy (inside orbit) to highest energy (outside orbits). • Electrons are arranged in a fixed orbit in 2, 8, 8, 8. • Bohr model only works up to atomic number20 (Ca)

  11. Valence Electrons • Valence Electrons = #electrons in outer orbit • Atoms are “HAPPY” when they have a full valence orbit. • They will find another atom to exchange or share electrons so they have a full valence orbit 1 Valence Electron

  12. Chemical Bonding • Atoms are “HAPPY” when they have a full valence orbit. • They will find another atom to exchange or share electrons so they have a full valence orbit.

  13. Atomic Structure BIG IDEAS • sub-atomic particles • Protons (+), Neutrons(0) in Nucleus • Electrons (-) in orbits • APES = Atomic # Proton# Electron# SAME • Bohr Model: • Fixed orbits 2, 8, 8, 8 electrons • Works up to Ca (#20) • Valence Electrons: • = electrons in outer orbit • Atoms are “HAPPY” when they have a full valence orbit. • They will find another atom to exchange or share valence electrons so they have a full valence orbit 1 Valence Electron

  14. Types of chemical bonds: Ionic • Metals to Non-metals, • Metals give electrons, Non-metals take electrons. • Metals =positive ions, • Nonmetals =negative ions.

  15. Types of chemical bonds: Covalent • non-metals to non-metals, share valence electrons, • 50% custody of electrons • EXCEPT for water which has polar covalent • Electrons spend more time with oxygen ( O =- side of molecule H = + side of molecule).

  16. Types of chemical bonds: Metallic • non-metals to non-metals, share valence electrons, • 50% custody of electrons • EXCEPT for water which has polar covalent • Electrons spend more time with oxygen ( O =- side of molecule H = + side of molecule).

  17. Types of Bonds BIG IDEAS Atoms Bond using Valence Electrons TO BE HAPPY

  18. Periodic Table BIG IDEAS • organized in • columns= Groups& rows= Periods • Ones digit of group # = # of valence electrons • Period#= tells us the last orbit which # is filled with valence electrons • Zig-zag Line divides Metals & Nonmetals

  19. Representing bonds: Bohr Model of Valence Electrons We do this to figure out how many atoms will bond with each other when forming compounds.

  20. Representing bonds: Lewis dots We do this to figure out how many atoms will bond with each other when forming compounds.

  21. Representing bonds: Oxidation # • 1. Find the oxidation numbers for each element from the periodic table. • 2. Write the number above & to the right of each element (it’s a superscript). • 3. Criss-cross the numbers without the sign: • the superscript for each element becomes the subscript for the other element.

  22. Bonding BIG IDEAS • Bohr Model & Lewis Dots work only up to Ca (atomic #20) • Oxidation Numbers (crisscross) work for ALL elements • The crisscross tells us how many atoms bond to make a HAPPY molecule • Then we write the Balanced equation to make it happen

  23. Balancing Equations Must obey Law of Conservation of Mass # of reactant atoms = # of product atoms for each type of atom You can only chance the coefficient, not the subscript!

  24. Balancing Tips • Subscripts • These are the numbers below the symbol • They tell how many atoms are bonded together in one molecule • For example C2H6 has 2C atoms bonded to 6H atoms • The subscripts are determined by the valence electrons • WE CAN’T CHANGE THE SUBSCRIPT!! • We find the subscripts by using: • Bohr Model • Lewis Dots • Criss-cross /oxidation # H H H C C H H H

  25. Balancing tips • Coefficients • These are the numbers in front of the symbol • They tell how many atoms or molecules we have • It multiplies the number of atoms or molecules (including the subscript) • Ex: 3Na = 3Na atoms 2 C2H6 = 2x2 = 4C atoms =2x6 = 12H atoms • IT IS THE ONLY NUMBER THAT WE CAN CHANGE!!

  26. Balancing BIG IDEAS • The crisscross tells us how many atoms bond to make a HAPPY molecule • Then we write the Balanced equation to make it happen • Must obey Law of Conservation of Mass • # of reactant atoms must = # of product atoms for each type of atom • can only chance the coefficient, not the subscript!

  27. Types of reactions • decomposition(break apart) • 2H2O2 + yeast 2H2 + 2O2 • synthesis(put together) • 2H2 +O2 2H2O • combustion(fire) • CH4 + O2(g)  CO2(g) + 2H2O(g) • single replacement (one pushes the other out) • Zn(s) + HCl(aq)  ZnCl2(aq) +H2 (s) • double replacement (the two switch) • PbI(aq) + K(NO3)(aq)  K(NO3)(aq) + PbI(s)

  28. Chemical Reactions BIG IDEAS • We want to PREDICT what happens when things react: • The type of reaction allows us to predict what type of chemical reaction will occur and the products; • Then, the crisscrosstells us how many atoms bond to make a HAPPY molecule in the products; • Then we write the Balanced equation to make it happen

  29. Doing Chemistry EXAMPLE • What happens when I put a piece of Zn in HCl? • Zn+ HCl ??? • Type of reaction MUST be Single replacement: • Zn+ HCl ZnCl?+H2 • The crisscrosstells us the formula is ZnCl2 and that little H will find a buddy • The BALANCED equation is: • Zn+ 2HCl ZnCl2+H2

  30. Aqueous Solutions H+ • Water has superpowers because it forms a polar covalent bond (unequal sharing of the electrons) • This allows water to surround and separate many compounds. • Acids & bases can only form in water • Acids:Forms H+ ions (steal electrons)when dissolved in water • Bases:Release OH- ions (force to take electrons)when dissolved in water OH-

  31. pH Scale • Measures whether a substance is an acid or a base. • pH scale goes from 0-14 • pH <7 =acidic • pH =7 =neutral (pure water) • pH >7 = bases

  32. H+ Aqueous Solutions BIG IDEAS • Water is a polar molecule which has superpowers • Most of chemistry happens in Aqueous solutions • Acids & bases can only form in water • Acids:Forms H+ ions (steal electrons) • Bases:Forms OH-ions (force to take electrons) • pH scale goes from 0-14 pH <7 =acidic pH =7 =neutral (pure water) pH >7 = bases

  33. THE FINAL BIG IDEA • All the Elements in the Universe were forged in the stars • Chemistry is the study of how these elements combine to make NEW SUBSTANCES • New substances form to make elements HAPPY when they make new molecules

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