metal characteristic: example: nonmetal characteristic: example: what do you know about different...
TRANSCRIPT
• Metal• Characteristic:
• Example:
• Nonmetal• Characteristic:
• Example:
What do you know about different elements?
• Physical properties: properties that can be determined without altering the chemical makeup of the material.
• Color, density, odor, melting point, boiling point, bendable etc.
• Material remains the same after you test for certain physical properties.
A.1 PROPERTIES MAKE THE DIFFERENCE
• Kind of chemical changes it undergoes.• Substance doesn’t stay the same after a
chemical change.• Ex. Rusting of iron, burning etc.
• Combustion – burning, involves oxygen.
Chemical properties
1. Pure metals have a high luster.2. Surfaces of some metals become dull when exposed to air3. Nitrogen gas, forms nitrogen oxides at the high temperatures of an
operating automobile engine.4. Milk turns sour if left too long at room temperature5. Diamonds are hard enough to be used as a coating for drill bits6. Metals are ductile7. Bread rises8. Argon is used to fill light bulbs to prevent the metal filament wire
inside the bulb from being destroyed through oxidation.9. Metals conduct heat and electricity.
Physical or chemical?
• What is a concern when manufacturing coins?– Cost, durability, reactivity of metal
A.3 properties matter: designing the penny
1980s copper became too expensive to be used as the primary metal in pennies.1943-zinc-plated steel pennies., corroded easily1982 zinc replaced copper, copper coating.More chemically reactive.97.5% zinc
History of the penny
• Metals – conducts electricity & heat, malleable, ductile
• Nonmetals – brittle, bad conductors• Metalloids (properties of metals and
nonmetals)
A.4 The Chemical Elements
• Mendeleev – arranged according to atomic mass• Mosley – arranged according to atomic number• Periodicity• Pg119• Atomic number - #protons• Atomic mass - #protons + #neutrons• isotopes
The Periodic Table
• Alkali • Alkali earth• Transition metals• Metalloids • Halogens • Noble gases • Lanthanides• actinides
Groups
• Arrangement of electrons• Metals tend to give electrons• Results in cations
What determines properties?
• http://www.youtube.com/watch?v=7jggPpaLyKk
A.13 It’s Only Money
• Sources and uses of metals: coin, clothing, engines, fertilizer…
• Earth’s composition– Atmosphere – N, O, Ar, He, Ne, C– Hydrosphere – water, salt, Mg, S, Ca– Lithosphere – silicates, coal, oil, carbonates,
oxides, sulfides, – Mantle – silicates, Mg, Fe– Core – Fe, Ni
SecB Earth’s Mineral Resources
• Lithosphere – solid part, chemical resources, petroleum, ore
• Ore – naturally occurring rock or mineral that can be mined
• Minerals – naturally occurring solid compounds containing the element or group of elements of interest.
• Mines:
• Africa – chromium 95%, cobalt 52%, manganese 80%
• China – Aluminum 17%• Pg. 136 ques.1-5
World’s Mines
• Ductility – drawn into wires• Brass, bronze• Alloy – mixture of metals melted together• Not very corrosive
• Element handbook worksheet
Copper
• Most metals are found combined with other elements in nature.
• Mined and refined• Formation of copper metal: reduction• Reduction – gain one or more electrons• Cu2+ Cu• Reduced comes from the ion charge number. 2+
0• Gets smaller
B.8 Mining and Refining
• Cu Cu2+ + 2e-• Oxidized – lose one or more electrons.• 0 2+ ion charge number
Formation of Copper(II) ions : oxidation
• One reactant loses e- and the other gains e-.• Another name = redox reactions• Cu + 2Ag+ Cu2+ + 2Ag• Which is reduced?• Ag• Which is oxidized?• Cu
Oxidation-reduction rxn.
• Electrometallurgy – using an electrical current to supply e- to metal ions. Reducing them 2+ 0
• Pyrometallurgy – treating metals and their ores with heat, carbon and carbon monoxide to provide e-
• Hydrometallurgy – treating with reactants in a water solution.
• Ex. Redox rxns.
Redox Rxn. To obtain Pure metals
• Law of conservation of matter: matter is neither created nor destroyed in a chemical reaction.
• Balanced chemical equation: number of atoms of each element is the same on the reactant and product sides.
• C + O2 CO2
• Diatomic – same element bonded to another of the same.
• GEN-U-INE
Sec. C Conserving Matter
2Cu + O2 __CuO
Coefficients – indicates the number of units of each substance involved in the chemical reaction.Formula unit – smallest unit of an ionic compound. Ionic compounds are called formula units because they form large crystals.Molecules – name for compounds made up of nonmetal+nonmetal.
1. Never touch subscripts!2. Balance polyatomic molecules first.3. Balance metals4. Balance nonmetals (save hydrogen and
oxygen for last)5. Make sure coefficients are in lowest ratio.
Rules for balancing equations
• Make a chart and list number of atoms of each element.
Reactants Products3 C 1 C8 H 2 H2 O 3 O
C3H8 + O2 CO2 + H2O
The Mole
• A way to group an amount of atoms together so to not deal with huge numbers.
• Amount of a substance that contains as many particles as there are atoms in exactly 12 g of carbon-12.
Just like: dozen, gross, …1 mole = 6.022 x 1023 atoms
Avogadro’s number = 6.022 x 1023 Number of particles in exactly one mole of a pure substance.
Molar Mass
• The mass of one mole of a pure substance.g/mol• The molar mass of an element = atomic mass unit• Ex. Carbon 12g 12g/mol
Example:2.00 mol He = _____g He
2.00 mol He x 4.00 g He = 8.00 g He1 mol He
C.7 Equations and Molar Relationships
Stoichiometry – using the chemical equation to solve for amount of products or reactants unknowns.2CuO + C 2Cu + CO2
23g ?g23gCuO x 1moleCuO x 2moleCu x 63.5gCu =18.4g 79.5gCuO 2mole CuO 1mole
C.9 Composition of Materials
• Percent composition – percent by mass of each material found in an item such as a coin.
A post-1982 penny with a mass of 2.500 g is composed of 2.4375 g zinc and 0.0625 g copper. What is its percent composition?2.4375g zinc x 100% = 97.50% zinc2.500g total0.0625g copper x 100% = 2.50% copper2.500g total
Practice question
Cu2S What is the percentage of Copper?
Contains 2 moles of Cu and 1 mole of S.%Cu = mass of Cu x 100% mass of Cu2S
127.10g Cu x 100% = 79.85% Cu 159.17gCu2S
C.12 Conservation in the Community
Depleting ResourcesRenewable resources – can be replenished by natural processes.Nonrenewable resources – cannot be readily replenished.Petroleum is decliningMetal mining is becoming less profitable because the ore contains a smaller percentage of the metal.