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Composition of the Earth Essential Questions 1. 2. Examine the differences between changes and properties of matter. How are subatomic particles arranged within an atom and is their a reason that they are arranged in this manner? 3. What is matter and how does it behave? 4. How is the periodic table used to identify the characteristics and properties of metals, nonmetals, and metalloids? 5. How are minerals identified? 6. Explain how minerals and rocks are a result of Earth’s regular pattern of change and natural cycles? 7. How are environmental resoruces classified? 8. What effect does human activities have on natural resources? 9. What are the drawbacks and benefits of current energy sources? 10. How can we provide the energy we need while maintaining ecological balance? Chemical and Physical Properties and Changes Physical Property: • can be observed without changing the substance • Examples: color, hardness, density, size, shape Physical Change: • matter changes its physical properties • no new substances are formed • State changes are physical changes • melting, boiling, freezing, evaporation, condensation Chemical Property: • determines how a substance will react to form new substances Chemical Change: • new substances are formed • Examples: rusting, rotting, burning, decaying To determine chemical and physical properties and changes, ask this: • Are new substances being formed or could they be formed? YES – chemical NO - physical • Is something happening or could something happen? YES – change NO - property Identify the following as a physical change, physical property, chemical change, or chemical property. 1. 2. 3. 4. 5. 6. Emeralds are green. Calcite is reacting with acid. Sugar is dissolving in water. Clouds form when water condenses. Water is boiling at 100°C. Acid rain will break down limestone. Atoms and Elements • element: • made up of one kind of atom • each has a name and chemical symbol on periodic table • atom: smallest part of element that has properties element • nucleus: central core of the atom • Atoms are made of three basic parts: • proton: positively charged, inside nucleus • neutron: no electric charge, inside nucleus • electron: negatively charged, outside nucleus # of protons and electrons are equal • compound: atoms of different elements chemically combined • mixture: two or more substances physically combined • can be separated by physical change • chemical formula: combination of chemical symbols to represent a compound • show # and type of elements Bohr Models • Created by Neil's Bohr. • Shows the as a small positively charged nucleus surrounded by negatively electrons. Bohr Models • Atomic number = number of protons and electrons • Rounded Mass Number – Atomic Number= Neutrons • Neutrons + Protons = Mass number Location of Subatomic Particles • Protons: inside Nucleus • Neutrons: inside Nucleus • Electrons: outside in orbitals Number of Electrons that can be held in each energy level. • Use the formula 2n2 to determine the number electrons to be held in each orbital. • N = the level one is trying to determine. • EXAMPLE • How many electrons can be held on the 3rd level? • 2(3)2= 18 electrons Example of (Al) Bohr Model • Aluminum • Protons: 11 (atomic number) • Electrons: 11 (atomic number) • Neutrons: 12 (rounded mass # - atomic number) Practice • Create Bohr models for the following in Groups! • • • • • Carbon (C) Neon (Ne) Silicon (Si) Copper (Cu) Sodium (Na) Homework • Create Bohr models for the following: • Iron (Fe) • Silver (Ag) • Mercury (Hg) Matter = the study of matter ► Matter = anything that has mass and takes up space (has volume) ► CHEMISTRY Classification of Matter Elements ► There are currently 118 known elements ► The elements are named by: - the scientist (Es-einsteinium) - the university (Bk-berkelium) - the town (Cf-californium) - its latin name (Au-aurum) http://en.wikipedia.org/wiki/List_of_chemical_element_name_etymologies Elements ► Each element has its own unique physical and chemical properties Element Physical Property Chemical Property Sodium-Na Solid, shiny, malleable Very reactive, loses e- Chlorine-Cl Gas, green Very reactive, gains e- Isotopes ► Atoms of the same element that have a different number of neutrons because their mass is different from the original element. ► Examples Carbon generally has a mass of 12, which means it will have 6 neutrons. Carbon-14 has a mass of 14, which means it will have 8 neutrons. Isotopes Periodic Table A chart of the elements ► Group/Family: - vertical column (18) - elements are listed with others having similar properties ► Period - horizontal rows (7) - elements having the same number of energy levels ► Metals ► Physical Properties: - malleable: bendable - ductile: stretches into thin wire - conducts heat & electricity easily - has luster ► Chemical Properties: - tend to lose e-’s - the more to the left on the periodic table, the more reactive/metallic Nonmetals ► Physical Properties: - brittle: breaks when bent - nonconductor of heat & electricity - dull ► Chemical Properties: - tend to gain e-’s - the more to the right on the periodic table, the more reactive/nonmetallic Metalloids ► Will tend to gain or lose electrons, depending on the element it bonds with ► Mixed properties Noble Gases Noble Gases ► Nonreactive due to the full outer energy level (*8 e-’s) ► Octet rule = ALL atoms “want” eight outer e-’s Halogens ► MOST reactive nonmetals ► Gaining 1 e- would give octet Alkali Metals ► Most reactive metals ► Losing 1 e- would give octet Valence e- = outermost e- Compounds Compounds ► Compound = two or more different elements chemically bonded ► Molecule = two or more atoms bonded together Compounds ► Why aren’t these compounds? ► Why are they molecules? Types of Compounds ► Ionic (ionic bond) - metal - nonmetal - formed by electron transfer ► Molecular (covalent bond) - nonmetal - nonmetal - formed by sharing of electrons Formulas ► Provide the: - type of elements - number of atoms of each element ► Examples: (count the atoms) C8H10N4O2 subscript Al(NO3)3 Types of Bonding 1. Ionic Bonds 2. Covalent Bonds Types of Bonding Ionic - metal - nonmetal - formed by electron transfer ► Covalent - nonmetal - nonmetal - formed by sharing of electrons ► Ion Formation (electron transfer) 1. cation formation: - metal atom loses valence electrons - metal ion with positive charge forms ► 2. anion formation: - nonmetal atom gains valence electrons - nonmetal ion with negative charge forms ► http://gpc.edu/~pgore/PhysicalScience/ionic_bond_animation.gif Ionic Bonding Simple Ionic Nomenclature ► Metal name goes first – no change ► Nonmetal name goes second – change ending to –ide. ► Number of atoms in formula doesn’t matter (WE DO NOT CARE ABOUT SUBSCRIPTS AT THIS POINT)! Ex: MgCl2 Li2O magnesium chloride lithium oxide Ionic Nomenclature (binary) Practice The number of atoms do NOT affect the name ► Ex: MgCl2 magnesium chloride ► 1. MgO 4. BeCl2 2. Li2O 5. K2S 3. AlF3 6. NaF Ionic Nomenclature (nonbinary) If there are more than 2 elements, a polyatomic ion must be present ► Simply write the names of the metal and the ion ► Ex: MgSO4 magnesium sulfate ► Na2CO3 Al(NO3)3 http://dbhs.wvusd.k12.ca.us/webdocs/Nomenclature/Polyatomic-FormulatoName.html Ionic Nomenclature (binary) compounds have 2 elements ► 1st element name (metal) is unchanged ► 2nd element name (nonmetal) ends –ide ► Binary ► Ex: NaCl sodium chloride http://misterguch.brinkster.net/practiceworksheets.html Ionic Bonding Writing Ionic Formulas ► RULES 1. the metal is always written first 2. total positive charges must equal total negative charges 3. use subscripts to state how many ions must be present in the formula 4. never include charges in the formula Ex: magnesium chloride Writing Binary Ionic Formulas 1. 2. 3. 4. 5. 6. 7. Calcium oxide Calcium chloride Lithium sulfide Lithium bromide Aluminum phosphide Aluminum iodide Aluminum oxide http://dbhs.wvusd.k12.ca.us/webdocs/Nomenclature/Binary-Fixed-NametoFormula.html Writing Nonbinary Ionic Formulas Match the metal charge to the charge of the poly ion by using subscripts ► Use parentheses on poly ion ONLY if multiplying by a subscript ► Ammonium (NH4+) is the ONLY positively charged polyatomic ion ► 1. 2. 3. 4. 5. 6. 7. 8. calcium carbonate lithium phosphate barium nitrate potassium chlorate ammonium chloride ammonium sulfate zinc chromate silver nitrate http://dbhs.wvusd.k12.ca.us/webdocs/Nomenclature/Polyatomic-NametoFormula.html The Stock System ► Transition elements may have more than one type of charge Metal Possible Charges Fe +2, +3 Cu +1, +2 Sn +2, +4 The Stock System ► 1. The charge can be determined from the: Name: a Roman numeral is used to give the charge Ex: copper (II) oxide Cu+2 + O-2 CuO Practice: tin (IV) chloride iron (II) sulfide The Stock System ► 2. The charge can be determined from the: Formula: work from the known charge on the anion and the rule that positive and negative charges must be equal Ex: Fe2O3 Oxygen has a known charge of -2 3 oxygens have a charge of -6 the 2 irons have a charge of +6 and each iron has a charge of +3 iron (III) oxide http://misterguch.brinkster.net/practiceworksheets.html The Stock System ► 1. 2. 3. 4. 5. Write the formula Iron (II) oxide Gold (III) chloride Tin (IV) bromide Mercury (II) chloride Manganese (II) chlorate http://dbhs.wvusd.k12.ca.us/webdocs/Nomenclature/Binary-Comm-NametoFormula.html The Stock System ► 1. 2. 3. 4. 5. Write the name: CuBr Fe2O3 Sn3P4 PbBr4 Hg2F2 http://dbhs.wvusd.k12.ca.us/webdocs/Nomenclature/Binary-Stock-FormulatoName.html Covalent Nomenclature ► Compounds having covalent bonds form molecules Molecular nomenclature uses prefixes to state how many atoms of each element are found in the compound ► Never use mono- with the 1st element ► 1 mono 2 di 3 tri 4 tetra 5 penta 6 hexa 7 hepta 8 octa 9 nona 10 deca Covalent Compounds ► NO METALS ALLOWED! Simple Molecular Nomenclature Ex: P2O5 ► Use prefix with first element diphosphorus ► Use prefix with second element AND end with –ide pentaoxide ► Do NOT use the mono prefix on the 1st element http://www.pafaculty.net/biology/keith/KR_Graph_site/molec_nomenclature_page.htm Binary Molecular Nomenclature ► ► 1. 2. 3. 4. 5. Ex: P2O5 is diphosphorus pentaoxide Name the following molecular compounds S2Cl2 UF6 ClO2 BF3 N 2 S5 http://dbhs.wvusd.k12.ca.us/webdocs/Nomenclature/Binary-Greek-FormulatoName.html Binary Molecular Nomenclature ► Write the formulas for the following molecular compounds: 1. Bromine trioxide Tetraarsenic decaoxide Dinitrogen trioxide Boron mononitride Xenon tetrafluoride 2. 3. 4. 5. Chemical Reactions Signs of Chemical Change ► 1. color change ► 2. formation of a gas ► 3. formation of a precipitate ► 4. change in energy (temp. change) - These are the most common A change in energy ALWAYS occurs A NEW substance with NEW properties is always formed Change in Energy ► Endothermic: energy is feels cold ► Exothermic: energy is feels warm Law of Conservation of Mass ► What goes in….must come out! Balancing Equations ► Reactants = substances combined that go into the reaction ► Products = new substances formed that come out of the reaction Reactants Products Chemical Equations A+B C+D REACTANTS PRODUCTS Balancing Equations ► law of conservation of mass: mass of the reactants must equal mass of the products mass Reactants mass Products ► We now know that (#atoms)(atomic mass) = mass ► This means that: #atoms Reactants #atoms Products Rules - Balancing Equations 1. 2. 1. Count the atoms of one element on both sides of the equation N2 + H2 NH3 Use coefficients (multiples) to increase atoms of an element N2 + 3H2 2NH3 NEVER change a formula (change/insert a subscript) N2 + H3 N2H3 Balancing Equations - practice 1. H2 + O2 ----> H2O 2. Mg + P4 ---> Mg3P2 3. Cu + O2 ----> Cu2O Balancing Equations - tips ► Look for polyatomic ions ► Count the ion as a unit CaCl2 + AgNO3 ----> AgCl + Ca(NO3)2 Balancing Equations - tips ► Check for elements that occur more than once on one side of an equation – sum the atoms. (NH4)2CO3 ---> NH3 + CO2 + H2O What is a Mineral? Must meet 5 criteria to be classified as a mineral 1. Occur naturally – can be found on Earth, not manmade 2. Inorganic - not formed from living things or their remains 3. Solid – have definite volume and shape 4. Definite chemical composition – element or compound 5. Crystal structure - atoms arranged in definite pattern that repeats itself, flat sides, sharp edges and corners • Minerals are very difficult to identify just by looking at them. Physical properties help identify minerals. 1. color – only a few minerals have a characteristic color 2. luster – describes the way a mineral reflects light • • metallic – reflects light the way polished metal does nonmetallic – does not reflect much light 3. hardness – ability of a mineral to resist being scratched • • most useful for mineral identification Moh’s Hardness Scale • p. 52 in your book • compares hardness of minerals to ten “standards” • numbered 1-10 • 1 is softest, 10 is hardest Moh’s Hardness Scale 4. streak – color of the powder left behind when a mineral is rubbed against a hard, rough surface 5. density – amount of matter in a given space; how closely packed the mineral is 6. crystal shape – six characteristic shapes 7. cleavage and fracture – describes the way a mineral breaks • • cleavage – split along smooth, definite surfaces fracture – breaks along rough, jagged edges Cleavage Fracture 8. special properties – properties characteristic of only 1 mineral • • • magnetic acid test taste Moh’s Hardness Scale Virtual Lab • http://academic.brooklyn.cuny.edu/geology/ leveson/core/linksa/hardex_2a.html What are Rocks? • Rock: hard substance composed of one or more minerals • Geologists: scientists who study rocks 3 Classifications for Rock I. Sedimentary Rocks • form from sediments that pile up and become pressed together over time Sedimentary Rock 3 Main Types of Sedimentary Rock 1. Clastic Rocks • made of pieces of other rocks 2. Organic • formed form material that once was living 3. Chemical • formed when a body of water dries up, leaving behind the minerals dissolved in the water II. Igneous Rocks • • • form when hot, liquid magma cools within the earth Classified by composition and texture 2 Kinds 1. extrusive rocks: formed from lava (at or near surface) 2. intrusive rocks: formed from magma (deep in the earth) Igneous Rock III. Metamorphic Rocks • form when heat, pressure, or chemical reactions change existing rocks into new rocks 2 Main Types classified by texture (arrangement of grains) • • 1. 2. Foliated – mineral crystals are arranged in layers Unfoliated – do not have bands Metamorphic Rock • Rock Cycle: continuous changing of rocks over a long period of time Rock Cycle Processes • • • • • Sedimentary: Cementation and Compaction Sediments: Weathering Metamorphic: Heat and Pressure Igneous: Cooling and Crystallization Magma: Melting The Rock Cycle Resources and Energy Types of Resources • Renewable Resources- Can be replaced within a human life-time or as they are used. • Examples: Air, water, plants • Nonrenewable Resources: A natural resource that cannot be re-made or re-grown at a scale comparable to its consumption. • Examples: Fossil Fuels (Oil, Coal, Petroleum) Ores • Deposits or minerals from which metals and nonmetals can be removed profitably. • Examples: Fe (iron) can be extracted from magnetite and hematite. Fossil Fuels • Coal, Petroleum, Natural Gas • Consists of hydrocarbons. • Hydrocarbons contain multiple hydrogen bonds. Coal • Dark-colored, organic rock. • Formed from the process or carbonization. • Carbonization: occurs when partially decomposed trees and other plants are buried in swamp mud. • Mined for consumption! HOW IS COAL MADE ??? Oil and Natural Gas • Found under ground between folds of rock and in areas of rock that are porous and contain the oils within the rock itself. • Drilled for consumption! HOW ARE OIL AND GAS MADE ??? Fossil Fuels and the Environment • Strip mining of coal leaves deep ditches where coal is removed, which allows erosion to act upon it. • Air Pollution is caused by burning of coal with a high sulfur content, which results in acid rain production. • Oil Spills occur due to drilling. Alternative Energy • Alternative energy resources other than fossil fuels. • Examples: Nuclear Fusion and Fission, Solar Energy, Geothermal Energy, Wind Energy, Hydroelectric Energy, and Biomass Nuclear Energy: Nonrenewable • Nuclear fission uses uranium to create energy. • Nuclear Fusion is used with many isotopes to create energy. • Two Types • Fission: Splitting Atomic Nuclei • Fusion: Combining Atomic Nuclei Nuclear Fission: Nonrenewable • Splitting of the nucleus of a large atom into two or more smaller nuclei to release a large amount of heat energy. Nuclear Fusion: Nonrenewable • Combining of smaller nuclei to form larger nuclei to release energy. • Solar Radiation is created in this way. Alternative (Renewable) Energy SOLAR • Energy from the sun Solar Power • Benefits • Abundant • No greenhouse gases, few other pollutants • Simple, minimal repair needed • Cheap over the long term • Negative • Has limitations, night, some locations better such as south rather than north facing slopes • Initial capital outlay can be high. (COST) GEOTHERMAL Energy from Earth’s heat. Geothermal Cons • Can be used for electricity generation, space heating, cooking & low temperature industrial • Inexpensive after initial outlay • No greenhouse gas emission Pros • Same problems as we see with oil drilling • Localized distribution- only assessable to certain areas WIND Energy from the wind. Effects of windpower Pros Cons • • • • • Some noise pollution • Metal blades interfere with TV & radio reception • No evidence for bird death, but can kill bats No greenhouse gases Cheap Abundant Simple BIOMASS Energy from burning organic or living matter. Biomass PROS CONS • Burning biomass gets rid of solid wastes • Creates Energy • Creates new markets for crops, which in turn creates revenue for farmers. • Releases CO2 and other gases associated with combustion • Creates solid waste from ash WATER or HYDROELECTRIC Energy from the flow of water. Hydroelectric Power PROS CONS • Can generate electricity • Can do mechanical work, e.g. grind grain • No greenhouse gases • Initial construction provides jobs • Flooding the land • Displacement of local inhabitants • Tectonic activities (Earthquakes) • Loss of species (aquatic & terrestrial) • Loss of normal nutrient flow down river