Chem 105 MacroExam 1
Dr. Smith Winter 2014
Disclaimer
• All the problems on here come from your textbook! If you need
more, I suggest working through micro-exams and...
Matter
• Matter
• Anything that has mass and occupies space
• The physical material of the universe
• Three States of Matt...
Properties
• Quantitative = Extensive
• Depend on amount of matter present
• Qualitative = Intensive
• Independent of amou...
Elements, Compounds, Mixtures
• Pure Substance
• Made up of only one substance (can be element or compound)
• Elements
• C...
Experiments to Review
• Cathode Ray Tube
• Discovery of Electron
• Gold Foil
• Discovered positively charged nucleus
• Oil...
Periodic Table: Elements
Atomic number:
Number of protons (and
electrons in neutral atom)
*unique to every element
Atomic ...
Atoms
• Nucleus
• Protons: positively charged
• Neutrons: no charge
• Electrons
• Around nucleus in orbitals
• Negitavely ...
Laws
• Uncertainty Principle
• Can know momentum or location of electron, not both at the same time
• Law of Constant Comp...
Measurements
• Number and SI unit (m, kg, s, K)
• Accurate: numbers close to the actual value
• Precise: numbers close to ...
Dimensional Analysis
• Can be your best friend!
• WRITE DOWN YOUR UNITS! WRITE DOWN YOUR UNITS! I promise
they can pretty ...
Practice Problems
• 1.52) The concentration of carbon monoxide in an urban
apartment is 48 µg/m3. What mass of carbon mono...
Periodic Trends
Families and groups: Alkali metals, Alkaline Earth Metals,
Halogens, Noble Gases; Metals, Nonmetals, Metal...
Light
• Light can be thought of as particle and a wave
• E=hv=hc/λ
• c=λν
• λ=h/mv <- DeBroglie
• Wavelength and Frequency...
Bohr Model
• Electrons in circular orbits in fixed, quantized energy levels
• Photon
• Absorb a photon to go up an energy ...
Quantum Mechanical Model
• Electrons in orbitals
• s = spherical
• Radial nodes starting at 2s
• p = peanut
• 1 planar nod...
Practice Problem
• 6.61) For a given value of the principal quantum number, n, how
do the energies of the s, p, d, and f s...
Quantum Numbers
• Pauli Exclusion Principle
• n=shell (1, 2, 3….)
• l=subshell (n-1 to 0) (0=s, 1=p, 2=d, 3=f…)
• ml=orien...
Practice Problem
• 6.56) Which orbital goes with the following quantum numbers?
Which are not allowed?
• 2, 1, -1, 1/2
• 1...
Bonding
• Ionic
• Usually metal and nonmetal
• Transfer of electrons
• Make compounds in lattice structures
• Formula weig...
Nomenclature
• Metal + Nonmetal = Ionic compound
• Charges designate formula, name the elements and add –ide to the end. C...
Lewis Dot Structures
• Count total valence electrons
• Least electronegative atom in the middle
• Fill octet, create multi...
Empirical and Molecular Formulas
• Empirical
• Whole number ratios of elements in compound
• Can be found with percent com...
Practice Problems
• 3.51) Determine the empirical and molecular formulas of each of
the following substances:
• Styrene, a...
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Chem 105 macro exam 1

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Chem 105 macro exam 1

  1. 1. Chem 105 MacroExam 1 Dr. Smith Winter 2014
  2. 2. Disclaimer • All the problems on here come from your textbook! If you need more, I suggest working through micro-exams and practice sheets/parallel example problems, seeing your TA, and looking in the book for more problems to work through over specific things your struggling with. • I will try, but this may not cover every little thing that will be on the exam. Be sure to go home and study on your own as well. • Remember to review your Mastering Chemistry homework!
  3. 3. Matter • Matter • Anything that has mass and occupies space • The physical material of the universe • Three States of Matter • Solids • have distinct volume & distinct shape • Liquids • have distinct volume but no fixed shape. May not fill a container completely. • Gases • no distinct shape • expand to fill their container
  4. 4. Properties • Quantitative = Extensive • Depend on amount of matter present • Qualitative = Intensive • Independent of amount present; help identify substances • Chemical Changes & Properties • Involve a reaction • Physical Changes & Properties • Can be observed without changing the identity of the substance • Melting, freezing, evaporating, density, mass, volume, dissolving to make a solution
  5. 5. Elements, Compounds, Mixtures • Pure Substance • Made up of only one substance (can be element or compound) • Elements • Can’t be broken down into smaller substances • Compounds • Can be broken down into elements • Two or more elements chemically combined • Mixtures • Two or more substances physically mixed together • Homogeneous • Uniform throughout; solution (like Kool-aid or milk) • Heterogeneous • Can see individual pieces (like trail mix or Italian dressing)
  6. 6. Experiments to Review • Cathode Ray Tube • Discovery of Electron • Gold Foil • Discovered positively charged nucleus • Oil Drop • Discovered charge of electron
  7. 7. Periodic Table: Elements Atomic number: Number of protons (and electrons in neutral atom) *unique to every element Atomic mass: amu/atom or grams/mole (that’s why 6.022*10^23 is such a cool number!) Average of all naturally occurring isotopes and their relative abundances Element Symbol
  8. 8. Atoms • Nucleus • Protons: positively charged • Neutrons: no charge • Electrons • Around nucleus in orbitals • Negitavely charged • Atomic Number • Number of protons • Ions • Different number of electrons; charged • cations (+) and anions (-) • Mass Number • Number of protons + neutrons • Isopotes • Same element (# protons) with different number of neutrons
  9. 9. Laws • Uncertainty Principle • Can know momentum or location of electron, not both at the same time • Law of Constant Composition • A pure substance is uniform throughout; one sugar molecule doesn’t differ from another sugar molecule • Law of Definite Proportions • Atoms combine in whole number ratios • Law of Conservation of Mass • Matter cannot be created nor destroyed (same amount before and after reaction)
  10. 10. Measurements • Number and SI unit (m, kg, s, K) • Accurate: numbers close to the actual value • Precise: numbers close to each other • Significant Figures: • All non-zeros are sig. figs. • Zeros between two non-zeros are sig. figs. • Zeros left of first non-zero are NOT sig. figs. • If #>or=1, all zeros right of decimal are sig. figs. • If #<1, all zeros at end of # and between non-zeros are sig. figs. • Trailing zeros may or may not be sig. figs. (That’s why we use scientific notation) but if you see them on the exam, don’t count them. • Add & Subtract, go to last common decimal place • Multiply & Divide, use least number of total sig figs
  11. 11. Dimensional Analysis • Can be your best friend! • WRITE DOWN YOUR UNITS! WRITE DOWN YOUR UNITS! I promise they can pretty much do the thinking for you, take advantage of that. • Start with what the problem gives you, know where you want to end up, use conversion factors to get from point A to point B • Conversion factors like: • Density -> mass/volume
  12. 12. Practice Problems • 1.52) The concentration of carbon monoxide in an urban apartment is 48 µg/m3. What mass of carbon monoxide in grams is present in a room measuring 11.0 ft X 11.5 ft X 20.5 ft? • 1.55) Gold can be hammered into extremely thin sheets called gold leaf. An architect wants to cover a 100 ft X 82 ft ceiling with gold leaf that is five-millionths of an inch thick. The density of gold dis 19.32 g/cm3, and gold costs $953 per troy ounce (1 troy ounce = 31.1034768 g). How much will it cost the architect to buy the necessary gold?
  13. 13. Periodic Trends Families and groups: Alkali metals, Alkaline Earth Metals, Halogens, Noble Gases; Metals, Nonmetals, Metalloids • Can tell ion’s oxidation number by its location on the periodic table—they all want to be like the noble gases! (full octet/shell) • Isoelectronic: same number electrons • Electronegativity • Size • Ionization Energy • Electron Affinity • Effective Nuclear Charge • Family Names • Cation and Anion Size
  14. 14. Light • Light can be thought of as particle and a wave • E=hv=hc/λ • c=λν • λ=h/mv <- DeBroglie • Wavelength and Frequency inversely proportional • Energy proportional to frequency • Wavelength: length of one complete wave • Frequency: cycles/second (Hz, S-1) • Photoelectric Effect • Blackbody Radiation • Electromagnetic Spectrum • Raul’s Mother Is Visiting Uncle Xavier’s Garden (Visible 400-700 nm)
  15. 15. Bohr Model • Electrons in circular orbits in fixed, quantized energy levels • Photon • Absorb a photon to go up an energy level (excited state) • Gives off a photon to go down an energy level (ground state) • 1/λ=R(1/n1 2-1/n2 2) • En=-hcRh(1/n2)
  16. 16. Quantum Mechanical Model • Electrons in orbitals • s = spherical • Radial nodes starting at 2s • p = peanut • 1 planar node and radial nodes starting at 3p • d = dlover leaf? • 2 planar nodes and radial nodes starting at 4d • f = flower (don’t worry too much about this one) • Each orbital holds two electrons • Remember transition metals lose s orbital electrons first • Electron Configurations • Expanded • Condensed using Noble Gas configuration • Cu and Cr exceptions • Why? Hund’s Rule
  17. 17. Practice Problem • 6.61) For a given value of the principal quantum number, n, how do the energies of the s, p, d, and f subshells vary for • Hydrogen? • A many-electron atom?
  18. 18. Quantum Numbers • Pauli Exclusion Principle • n=shell (1, 2, 3….) • l=subshell (n-1 to 0) (0=s, 1=p, 2=d, 3=f…) • ml=orientation (-l to l) • ms=spin (-1/2 or +1/2)
  19. 19. Practice Problem • 6.56) Which orbital goes with the following quantum numbers? Which are not allowed? • 2, 1, -1, 1/2 • 1, 0, 0, -1/2 • 3, -3, 2, 1/2 • 3, 2, -2, -1/2 • 2, 0, -1, 1/2 • 0, 0, 0, -1/2 • 4, 2, 1, 1/2 • 5, 3, 0, 1/2
  20. 20. Bonding • Ionic • Usually metal and nonmetal • Transfer of electrons • Make compounds in lattice structures • Formula weight • Covalent • Usually two nonmetals • Sharing of electrons • Make molecules • Molecular weight
  21. 21. Nomenclature • Metal + Nonmetal = Ionic compound • Charges designate formula, name the elements and add –ide to the end. Cation first. • Remember transition metals can have different charges so specify with roman numerals • Nonmetal + Nonmetal = Covalent molecule • Use prefixes and add –ide to the end • Polyatomic Ions • Nick the Camel –ate a Clam for Supper in Phoenix • Hypo-ite, ite, ate, per-ous • Acids • If you ―–ate‖ too much you feel ―–ic‖ky • ―-ite‖s like Nephites and Lamanites are people like ―-ous‖ • Hypo-ous, ous, ic, per-ic  increasing O • Hydro-ic
  22. 22. Lewis Dot Structures • Count total valence electrons • Least electronegative atom in the middle • Fill octet, create multiple bonds if too many electrons • Resonance structures: none actually what the molecule looks like, it’s a hybrid of all of them • Formal charges • Bond strengths and lengths • Single, double, triple
  23. 23. Empirical and Molecular Formulas • Empirical • Whole number ratios of elements in compound • Can be found with percent compositions • Assume 100 g, divide by smallest number of moles, and put in whole number ratios • Molecular • Actual number of each element in molecule • Need molar mass to determine • When doing stoichiometry, most important step is mole-to-mole ratio
  24. 24. Practice Problems • 3.51) Determine the empirical and molecular formulas of each of the following substances: • Styrene, a compound used to make Styrofoam cups and insulation, contains 92.3% C and 7.7% H by mass and has a molar mass of 104 g/mol • Caffeine, a stimulant found in coffee, contains 49.5% C, 5.15% H, 28.9% N, and 16.5% O by mass and has a molar mass of 195 g/mol • Monosodium glutamate (MSG), a flavor enhancer in certain foods, contains 35.51% C, 4.77% H, 37.85% O, 8,29% N, and 13.60% Na, and has a molar mass of 169 g/mol

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