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Mark Rosengarten’s Amazing Chemistry Powerpoint Presentation!. Aligned to the New York State Standards and Core Curriculum for “The Physical Setting-Chemistry” Can be used in any high-school chemistry class! Please give the link to this file to your chemistry students! www.markrosengarten.com
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Mark Rosengarten’s Amazing Chemistry Powerpoint Presentation! • Aligned to the New York State Standards and Core Curriculum for “The Physical Setting-Chemistry” • Can be used in any high-school chemistry class! • Please give the link to this file to your chemistry students! www.markrosengarten.com • Enjoy it!!! A LOT of work has gone into bringing you this work, so please credit me when you use it! (c) 2006, Mark Rosengarten
Outline for Review 1) The Atom (Nuclear, Electron Config) 2) Matter (Phases, Types, Changes) 3) Bonding (Periodic Table, Ionic, Covalent) 4) Compounds (Formulas, Reactions, IMAF’s) 5)Math of Chemistry (Formula Mass, Gas Laws, Neutralization, etc.) 6) Kinetics and Thermodynamics (PE Diagrams, etc.) 7) Acids and Bases (pH, formulas, indicators, etc.) 8) Oxidation and Reduction (Half Reactions, Cells, etc.) 9) Organic Chemistry (Hydrocarbons, Families, Reactions) (c) 2006, Mark Rosengarten
The Atom 1) Nucleons 2) Isotopes 3) Natural Radioactivity 4) Half-Life 5) Nuclear Power 6) Electron Configuation 7) Development of the Atomic Model (c) 2006, Mark Rosengarten
Nucleons • Protons: +1 each, determines identity of element, mass of 1 amu, determined using atomic number, nuclear charge • Neutrons: no charge, determines identity of isotope of an element, 1 amu, determined using mass number - atomic number (amu = atomic mass unit) • 3216S and 3316S are both isotopes of S • S-32 has 16 protons and 16 neutrons • S-33 has 16 protons and 17 neutrons • All atoms of S have a nuclear charge of +16 due to the 16 protons. (c) 2006, Mark Rosengarten
Isotopes • Atoms of the same element MUST contain the same number of protons. • Atoms of the same element can vary in their numbers of neutrons, therefore many different atomic masses can exist for any one element. These are called isotopes. • The atomic mass on the Periodic Table is the weight-average atomic mass, taking into account the different isotope masses and their relative abundance. • Rounding off the atomic mass on the Periodic Table will tell you what the most common isotope of that element is. (c) 2006, Mark Rosengarten
Weight-Average Atomic Mass • WAM = ((% A of A/100) X Mass of A) + ((% A of B/100) X Mass of B) + … • What is the WAM of an element if its isotope masses and abundances are: • X-200: Mass = 200.0 amu, % abundance = 20.0 % • X-204: Mass = 204.0 amu, % abundance = 80.0% • amu = atomic mass unit (1.66 × 10-27 kilograms/amu) (c) 2006, Mark Rosengarten
Most Common Isotope • The weight-average atomic mass of Zinc is 65.39 amu. What is the most common isotope of Zinc? Zn-65! • What are the most common isotopes of: • Co Ag • S Pb • FACT: one atomic mass unit (1.66 × 10-27 kilograms) is defined as 1/12 of the mass of an atom of C-12. • This method doesn’t always work, but it usually does. Use it for the Regents exam. (c) 2006, Mark Rosengarten
Natural Radioactivity • Alpha Decay • Beta Decay • Positron Decay • Gamma Decay • Charges of Decay Particles • Natural decay starts with a parent nuclide that ejects a decay particle to form a daughter nuclide which is more stable than the parent nuclide was. (c) 2006, Mark Rosengarten
Alpha Decay • The nucleus ejects two protons and two neutrons. The atomic mass decreases by 4, the atomic number decreases by 2. • 23892U (c) 2006, Mark Rosengarten
Beta Decay • A neutron decays into a proton and an electron. The electron is ejected from the nucleus as a beta particle. The atomic mass remains the same, but the atomic number increases by 1. • 146C (c) 2006, Mark Rosengarten
Positron Decay • A proton is converted into a neutron and a positron. The positron is ejected by the nucleus. The mass remains the same, but the atomic number decreases by 1. • 5326Fe (c) 2006, Mark Rosengarten
Gamma Decay • The nucleus has energy levels just like electrons, but the involve a lot more energy. When the nucleus becomes more stable, a gamma ray may be released. This is a photon of high-energy light, and has no mass or charge. The atomic mass and number do not change with gamma. Gamma may occur by itself, or in conjunction with any other decay type. (c) 2006, Mark Rosengarten
Charges of Decay Particles (c) 2006, Mark Rosengarten
Half-Life • Half life is the time it takes for half of the nuclei in a radioactive sample to undergo decay. • Problem Types: • Going forwards in time • Going backwards in time • Radioactive Dating (c) 2006, Mark Rosengarten
Going Forwards in Time • How many grams of a 10.0 gram sample of I-131 (half-life of 8 days) will remain in 24 days? • #HL = t/T = 24/8 = 3 • Cut 10.0g in half 3 times: 5.00, 2.50, 1.25g (c) 2006, Mark Rosengarten
Going Backwards in Time • How many grams of a 10.0 gram sample of I-131 (half-life of 8 days) would there have been 24 days ago? • #HL = t/T = 24/8 = 3 • Double 10.0g 3 times: 20.0, 40.0, 80.0 g (c) 2006, Mark Rosengarten
Radioactive Dating • A sample of an ancient scroll contains 50% of the original steady-state concentration of C-14. How old is the scroll? • 50% = 1 HL • 1 HL X 5730 y/HL = 5730y (c) 2006, Mark Rosengarten
Nuclear Power • Artificial Transmutation • Particle Accelerators • Nuclear Fission • Nuclear Fusion (c) 2006, Mark Rosengarten
Artificial Transmutation • 4020Ca + _____ -----> 4019K + 11H • 9642Mo + 21H -----> 10n + _____ • Nuclide + Bullet --> New Element + Fragment(s) • The masses and atomic numbers must add up to be the same on both sides of the arrow. (c) 2006, Mark Rosengarten
Particle Accelerators • Devices that use electromagnetic fields to accelerate particle “bullets” towards target nuclei to make artificial transmutation possible! • Most of the elements from 93 on up (the “transuranium” elements) were created using particle accelerators. • Particles with no charge cannot be accelerated by the charged fields. (c) 2006, Mark Rosengarten
Nuclear Fission • 23592U + 10n 9236Kr + 14156Ba + 3 10n + energy • The three neutrons given off can be reabsorbed by other U-235 nuclei to continue fission as a chain reaction • A tiny bit of mass is lost (mass defect) and converted into a huge amount of energy. (c) 2006, Mark Rosengarten
Chain Reaction (c) 2006, Mark Rosengarten
Nuclear Fusion • 21H + 21H 42He + energy • Two small, positively-charged nuclei smash together at high temperatures and pressures to form one larger nucleus. • A small bit of mass is destroyed and converted into a huge amount of energy, more than even fission. (c) 2006, Mark Rosengarten
Electron Configuration • Basic Configuration • Valence Electrons • Electron-Dot (Lewis Dot) Diagrams • Excited vs. Ground State • What is Light? (c) 2006, Mark Rosengarten
Basic Configuration • The number of electrons is determined from the atomic number. • Look up the basic configuration below the atomic number on the periodic table. (PEL: principal energy level = shell) • He: 2 (2 e- in the 1st PEL) • Na: 2-8-1 (2 e- in the 1st PEL, 8 in the 2nd and 1 in the 3rd) • Br: 2-8-18-7 (2 e- in the 1st PEL, 8 in the 2nd, 18 in the 3rd and 7 in the 4th) (c) 2006, Mark Rosengarten
Valence Electrons • The valence electrons are responsible for all chemical bonding. • The valence electrons are the electrons in the outermost PEL (shell). • He: 2 (2 valence electrons) • Na: 2-8-1 (1 valence electron) • Br: 2-8-18-7 (7 valence electrons) • The maximum number of valence electrons an atom can have is EIGHT, called a STABLE OCTET. (c) 2006, Mark Rosengarten
Electron-Dot Diagrams • The number of dots equals the number of valence electrons. • The number of unpaired valence electrons in a nonmetal tells you how many covalent bonds that atom can form with other nonmetals or how many electrons it wants to gain from metals to form an ion. • The number of valence electrons in a metal tells you how many electrons the metal will lose to nonmetals to form an ion. Caution: May not work with transition metals. • EXAMPLE DOT DIAGRAMS (c) 2006, Mark Rosengarten
Example Dot Diagrams Carbon can also have this dot diagram, which it has when it forms organic compounds. (c) 2006, Mark Rosengarten
Excited vs. Ground State • Configurations on the Periodic Table are ground state configurations. • If electrons are given energy, they rise to higher energy levels (excited state). • If the total number of electrons matches in the configuration, but the configuration doesn’t match, the atom is in the excited state. • Na (ground, on table): 2-8-1 • Example of excited states: 2-7-2, 2-8-0-1, 2-6-3 (c) 2006, Mark Rosengarten
What Is Light? • Light is formed when electrons drop from the excited state to the ground state. • The lines on a bright-line spectrum come from specific energy level drops and are unique to each element. • EXAMPLE SPECTRUM (c) 2006, Mark Rosengarten
EXAMPLE SPECTRUM This is the bright-line spectrum of hydrogen. The top numbers represent the PEL (shell) change that produces the light with that color and the bottom number is the wavelength of the light (in nanometers, or 10-9 m). No other element has the same bright-line spectrum as hydrogen, so these spectra can be used to identify elements or mixtures of elements. (c) 2006, Mark Rosengarten
Development of the Atomic Model • Thompson Model • Rutherford Gold Foil Experiment and Model • Bohr Model • Quantum-Mechanical Model (c) 2006, Mark Rosengarten
Thompson Model • The atom is a positively charged diffuse mass with negatively charged electrons stuck in it. (c) 2006, Mark Rosengarten
Rutherford Model • The atom is made of a small, dense, positively charged nucleus with electrons at a distance, the vast majority of the volume of the atom is empty space. Alpha particles shot at a thin sheet of gold foil: most go through (empty space). Some deflect or bounce off (small + charged nucleus). (c) 2006, Mark Rosengarten
Bohr Model • Electrons orbit around the nucleus in energy levels (shells). Atomic bright-line spectra was the clue. (c) 2006, Mark Rosengarten
Quantum-Mechanical Model • Electron energy levels are wave functions. • Electrons are found in orbitals, regions of space where an electron is most likely to be found. • You can’t know both where the electron is and where it is going at the same time. • Electrons buzz around the nucleus like gnats buzzing around your head. (c) 2006, Mark Rosengarten
Matter 1) Properties ofPhases 2) Types of Matter 3) Phase Changes (c) 2006, Mark Rosengarten
Properties of Phases • Solids: Crystal lattice (regular geometric pattern), vibration motion only • Liquids: particles flow past each other but are still attracted to each other. • Gases: particles are small and far apart, they travel in a straight line until they hit something,they bounce off without losing any energy, they are so far apart from each other that they have effectively no attractive forces and their speed is directly proportional to the Kelvin temperature (Kinetic-Molecular Theory, Ideal Gas Theory) (c) 2006, Mark Rosengarten
Solids The positive and negative ions alternate in the ionic crystal lattice of NaCl. (c) 2006, Mark Rosengarten
Liquids When heated, the ions move faster and eventually separate from each other to form a liquid. The ions are loosely held together by the oppositely charged ions, but the ions are moving too fast for the crystal lattice to stay together. (c) 2006, Mark Rosengarten
Gases Since all gas molecules spread out the same way, equal volumes of gas under equal conditions of temperature and pressure will contain equal numbers of molecules of gas. 22.4 L of any gas at STP (1.00 atm and 273K) will contain one mole (6.02 X 1023) gas molecules. Since there is space between gas molecules, gases are affected by changes in pressure. (c) 2006, Mark Rosengarten
Types of Matter • Substances (Homogeneous) • Elements (cannot be decomposed by chemical change): Al, Ne, O, Br, H • Compounds (can be decomposed by chemical change): NaCl, Cu(ClO3)2, KBr, H2O, C2H6 • Mixtures • Homogeneous: Solutions (solvent + solute) • Heterogeneous: soil, Italian dressing, etc. (c) 2006, Mark Rosengarten
Elements • A sample of lead atoms (Pb). All atoms in the sample consist of lead, so the substance is homogeneous. • A sample of chlorine atoms (Cl). All atoms in the sample consist of chlorine, so the substance is homogeneous. (c) 2006, Mark Rosengarten
Compounds • Lead has two charges listed, +2 and +4. This is a sample of lead (II) chloride (PbCl2). Two or more elements bonded in a whole-number ratio is a COMPOUND. • This compound is formed from the +4 version of lead. This is lead (IV) chloride (PbCl4). Notice how both samples of lead compounds have consistent composition throughout? Compounds are homogeneous! (c) 2006, Mark Rosengarten
Mixtures • A mixture of lead atoms and chlorine atoms. They exist in no particular ratio and are not chemically combined with each other. They can be separated by physical means. • A mixture of PbCl2 and PbCl4 formula units. Again, they are in no particular ratio to each other and can be separated without chemical change. (c) 2006, Mark Rosengarten
Phase Changes • Phase Change Types • Phase Change Diagrams • Heat of Phase Change • Evaporation (c) 2006, Mark Rosengarten
Phase Change Types (c) 2006, Mark Rosengarten
Phase Change Diagrams AB: Solid Phase BC: Melting (S + L) CD: Liquid Phase DE: Boiling (L + G) EF: Gas Phase Notice how temperature remains constant during a phase change? That’s because the PE is changing, not the KE. (c) 2006, Mark Rosengarten
Heat of Phase Change • How many joules would it take to melt 100. g of H2O (s) at 0oC? • q=mHf = (100. g)(334 J/g) = 33400 J • How many joules would it take to boil 100. g of H2O (l) at 100oC? • q=mHv = (100.g)(2260 J/g) = 226000 J (c) 2006, Mark Rosengarten
Evaporation • When the surface molecules of a gas travel upwards at a great enough speed to escape. • The pressure a vapor exerts when sealed in a container at equilibrium is called vapor pressure, and can be found on Table H. • When the liquid is heated, its vapor pressure increases. • When the liquid’s vapor pressure equals the pressure exerted on it by the outside atmosphere, the liquid can boil. • If the pressure exerted on a liquid increases, the boiling point of the liquid increases (pressure cooker). If the pressure decreases, the boiling point of the liquid decreases (special cooking directions for high elevations). (c) 2006, Mark Rosengarten