Engineering Materials Flashcards
(229 cards)
1
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Refers to the group of materials that are used in the construction of manmade structures and components.
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Engineering Materials
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Selection of Materials for Engineering purposes (3)
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Availability, Sustainability, and Cost
3
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is the smallest unit of matter that retains all of the chemical properties of an element. Combine to form molecules, which then interact to form solids, gases, or liquids.
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Atom
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Atom consists of three basic particles
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proton (positive charge), neutron (no charge), electron (negative charge)
5
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describes the orbitals occupied by electrons on the atom.
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Electron Configurations
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states that each successive electron occupies the lowest energy orbital available and dictates how electrons are filled in the atomic orbitals of an atom in its ground state.
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Aufbau Principle
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states that, in an atom or molecule, no two electrons can have the same four electronic quantum numbers.
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Pauli’s Exclusion Principle
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Every orbital in a sublevel is singly occupied before any orbital is doubly occupied. All of the electrons are singly occupied orbitals have the same spin.
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Hund’s Rule
9
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are formed by the joining of two or more atoms. is the physical phenomenon of chemical substances being held together by attraction of atoms though sharing
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Chemical Bonding
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involve sharing of a pair of valence electrons by two atoms
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Covalent Bonds
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For atoms with the largest electronegativity differences (such as metals with nonmetals)
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Ionic Bonds
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typically represented as being transferred from the metal atom to the nonmetal.
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Valence Electrons
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is the sharing of many detached electrons, where the electrons act as a glue giving the substance a definite structure.
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Metallic Bonds
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conduct heat well because of delocalized electrons. The electrons drift slowly through the structure as the metal is heated. As the metal heats up, the electrons move faster.
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Conductivity of Metals
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energy is created by electrons in motion Because the valence electrons in metals are relatively free to move about when you apply a negative charge to the end of a piece of metal and a positive charge to the other end.
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Electrical Conductivity of Metals
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The delocalized electrons of the metallic bond in the “sea” of electrons allow the metal atoms to roll over each other when stress is applied.
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Malleability and Ductility
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Physical Properties of Metal
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appearance, color, size and shape, luster, weight, density, melting point, and boiling point.
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are those associated with the ability of the material to resist mechanical forces and load
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Mechanical Properties of Metals
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is the ability to resist externally applied forces without breaking or yielding
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Strength
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ability of a material to resist deformation under stress
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Stiffness
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is the property of a material to regain its original shape after deformation when the external forces are removed. Desirable for materials used in tools and machines.
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Elasticity
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property of material that retains the deformation produced under load permanently.
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Plasticity
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Is the property of a material enabling it to be drawn into the wire with the application of tensile force.
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Ductility
24
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is the opposite of Ductility. Property of breaking of a material with little permanent distortion.
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Brittleness
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special case of ductility which permits materials to be rolled or hammered into thin sheets.
Malleability
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is a property of a material to resist a fracture due to high-impact loads like hammer blows.
Toughness
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is the property of a material which refers to a relative case with which a material can be cut.
Machinability
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is the property of a material to absorb energy and to resist shock and impact loads
Resilience
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When a part is subjected to constant stress at high temperature for a long period of time.
Creep
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is subjected to repeat stresses, it fails at stresses below the yield
Fatigue
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it is a very important property of the metals and has wide variety of meanings.
Hardness
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Hardness of a metal may be determined by (4)
Brinell, Rockwell, Vickers, Shore Scleroscope
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Thermal Properties of Metals
Thermal conductivity, Expansion coefficient, Resistivity, Thermal shock resistance, and Thermal diffusivity.
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Electrical Properties of Metals
Conductivity, resistivity, dielectric strength, thermoelectricity, superconductivity, and electrical hysteresis.
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Chemical Properties of Metals
Reactivity, Corrosion resistance, polymerization, composition, acidity, and alkalinity
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Optical Properties of Metals
Reflectivity, Refractivity, absorptivity, transparency, opaqueness, color, and luster.
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Metallurgical Properties of Metals
Grain size, heat treatment done/required, anisotropy, and hardenability
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Classification of Engineering Materials
Metal, Composite, Ceramic, Polymer
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Systematic Arrangement or Division of Materials
General Properties, Nature of Materials, Applications
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most commonly used class of engineering material, formed by combining a metal with one or more other metallic and/or non-metallic materials.
Metals
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containing a high proportion of the element iron. The strongest materials available are used for applications where high strength is required at a relatively low cost
Ferrous Metals
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have iron as the base element. Mos common metal alloys in use due to the abundance or iron.
Ferrous Alloys
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is an important alloying element in all ferrous alloys. Higher level of carbon increase strength and hardness, and decreases ductility and weldability
Carbon
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basically just mixture of carbon and iron
Carbon Steel
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contains between 0.30% carbon. Low strength but high ductility. Very weldable and is inexpensive to produce.
Low-Carbon Steel
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contains between about 0.30% to 0.70% carbon.
Medium-Carbon Steel
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contains between 0.70% to 1.40%
High-Carbon Steel
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commonly called alloy steels, contains less than about 8% total alloying ingredients. Typically stronger than carbon steels and have better corrosion resistance.
Low-Alloy Steel
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primarily used to make tooling for use in manufacturing.
Tool Steel
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have good corrosion resistance, mostly due to the addition of chromium as an alloying ingredient.
Stainless Steel
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a ferrous alloy containing high levels of carbon, generally greater than 2%. The carbon present in _____ can take the form of graphite or carbide
Cast Iron
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Advantages of Cast Iron
Better corrosion resistance, high strength in compression, easy to cast.
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Disadvantages of Cast Iron
Very brittle, poor weldability
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The carbon is in the form of graphite flakes. Has low tensile strength, high compressive strength, and no ductility. free graphite in its structure acts as a lubricant.
Gray Cast Iron
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Resulting material of Gray Cast Iron because the magnesium causes the graphite flakes to form into spherical nodules. has good strength, ductility, and machinability.
Ductile Cast Iron (Nodular Cast Iron)
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has carbon in the form of carbide (known as cementite) which is a hard constituent of iron. Primarily used for wear-resisting components as well as for the production of malleable cast iron
White Cast Iron
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used for machine parts for which the steel forgings would be too expensive.
Malleable Cast Iron
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the purest iron which contains at least 99.5% iron but may contain up to 99.9% iron.
Wrought Iron
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materials refer to the remaining metals known as to mankind.
Non-Ferrous Metals
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Non-Ferrous Materials Characteristics (4)
Ease of Fabrication, Resistance to corrosion, Electrical and thermal conductivity, and weight
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a white metal produced by electrical processes from its oxide (alumina), which is prepared from a clayey called bouxite. Light metal has a specific gravity of 2.7 and a melting point of 658 C. Tensile strength varies from 90 MPa to 150 MPa.
Aluminium
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Composed of 95% Aluminium, 4% copper, 0.5% manganese, and 0.5% magnesium.
Duralumin
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if the metal is allowed to age for 3 or 4 days, it will be hardened.
Age Hardening
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also called copper-aluminium alloy. The addition of 4% copper to pure aluminium increases its strength and machinability.
Y-Alloy
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Made by melting the aluminium with 2 to 10% magnesium in a vacuum and then cooling it in a vacuum or under pressure of 100 to 200 atmospheres. Contains about 1.75% of copper.
Magnalium
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An alloy of aluminum and magnesium with a small quantity of chromium.
Hindalium
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is a group of nickel alloys, primarily composed of nickel (from 52 to 67%) and copper, with the small amounts of iron, manganese, carbon, and silicon.
Monel
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is a nickel-chromium alloy that is classified as superalloy because of its high-performance qualities and resistance to corrosion and oxidation
Inconel
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is a nickel-molybdenum-chromium superalloy with an addition of tungsten designed to have excellent corrosion resistance in severe environments.
Hastelloy
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one of the most widely used non-ferrous metals in industry. Its specific gravity is 8.9 and its melting point is 1083 C. Tensile strength varies from 150 MPa to 400 MPa.
Copper
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most widely used copper zinc alloy is brass. Fundamentally a binary alloy of copper with zinc each 50%.
Copper-Zinc Alloys (Brass)
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composition of 75 to 95% copper and 5 to 25% tin.
Copper-tin alloys (Bronze)
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is an alloy of copper, tin, and zinc. Usually 88% copper, 10% tin, and 2% zinc. Also known as Admiralty gun metal.
Gun Metal
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a blush grey metal having specific gravity 11.36 and melting point of 326 C.
Lead
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It is used for making important alloys, fine soldier, as a protective coating for iron and steel sheets and for making tin foil.
Tin
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These alloys can be casted easily with a good finish at fairly lo temperatures.
Zinc Base Alloys
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are widely used in engineering industry on account of their high mechanical strength properties, corrosion resistance.
Nickel Base Alloys
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an important alloy of nickel and copper. It has tensile strength from 390 MPa to 460 MPa.
Monel Metal
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It consists of 80% nickel, 14% chromium, and 6% iron. Its specific gravity 8.55 gravity and its melting point 1395 C
Inconel Metal
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Consists of 65% nickel, 15% chromium, and 20% iron
Nichrome
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Consists of 80% nickel and 20% chromium.
Nimonic
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These are non- metallic materials that do not exist in nature. They combine good resistance with ease of manufacture, being used for the joining of metallic components.
Synthetic Materials
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so diverse that only a few can be listed here to give basic introduction to some applications.
Natural Materials
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naturally occurring fibrous composite material used for the manufacture of casting patterns.
Wood
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used for hydraulic and compressed air hoses and oil seals
Rubber
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This is a hardwearing, abrasion-resistant material with excellent weathering properties.
Glass
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widely used in abrasive and is a naturally occurring aluminum oxide.
Emery
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produced by baking naturally occurring clays at high temperatures.
Ceramic
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can be used for cutting tools for operation at high speeds for metal finishing where surface finish is greater importance.
Diamonds
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Used as bearing lubricants, cutting fluids, and fuels.
Oils
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used as an alloying element and also for the manufacture of semiconductor devices.
Silicon
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are solid compounds that may consist of metallic or non-metallic elements.
Ceramics
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Characteristics of Ceramics:
Brittleness, High Thermal and electrical resistance, High resistance to corrosion, opaque, and high temperature stability.
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Uses of Ceramics
Food Storage, Roofing Tiles, Bricks Sewer pipes, Insulators in electric equipment and light fixtures, oven walls, space shuttle insulation.
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are common materials and are seen in applications including windows, lenses, and containers
Glass
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Common processes used to form glass
heating until melting then pouring into mold, until soft and then rolling, until soft then blowing into desired shapes.
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materials that, after mixing with water, form a paste that then hardens.
Cements
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Common cement
Plaster of Paris
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very common ceramic materials.
Clay Products
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Primary classifications of cement
structural clay products and whitewares
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can withstand high temperatures and extreme environments
Refractories
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are hard materials that are used to cut, grind, and wear away other softer materials.
Abrasives
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Factors affecting materials properties
Heat Treatments, Processing, Environmental Reactions
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Unless steel structures are regularly maintained by rest neutralizations.
Resting of Steel
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are materials that consist of molecules formed by long chains of repeating units.
Polymer
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is based on their response to heat. If heat is applied it will soften and melt
Thermoplastic Polymers
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will not melt upon reheating.
Thermosetting Polymers
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are highly polymers with mechanical properties similar to rubber.
Elastomers
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is the only planet in the solar system with an atmosphere that can sustain life.
Earth
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is the layer closest to Earth's surface, about 10 km above the surface reaching about 215 K. 4 to 12 miles (7 to 20 km). It contains most of our weather.
Troposphere
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is the second layer. It starts above the troposphere and ends about 31 miles (50 km) reaching maximum 275 K, The air here is very dry, thousand times thinner here than it is at sea level.
Stratosphere
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starts at 31 miles (50 km) and extends to 53 miles (85 km) high. Meteors burn up in this layer
Mesosphere
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it extends from about 56 miles (90 km) to between 310 miles and 620 miles (500 and 1,000 km). Temperatures can get up to 2,700 degrees F (1,500 C). The temperature increases is caused by absorption of energetic ultraviolet and X-ray radiation. It is also the layer where auroras occur
Thermosphere
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The region of the atmosphere above about 80 km
Ionosphere
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is the outermost layer of the Earth's surface. It starts with an altitude of 500 km and goes about 10,000 km. Extremely thin and is where the atmosphere merges into outerspace.
Exosphere
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where charged particles spiral along the magnetic field lines. 3,000 and 16,000 km above the globe.
Magnetosphere
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radiation belts
Van Allen
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boundary between the stratosphere and troposphere
Tropopause
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boundary between mesosphere and stratosphere
Stratopause
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boundary between the mesosphere and the thermosphere
Mesopause
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Composition of the atmosphere
Nitrogen - 78%
Oxygen - 21%
Argon - 0.93%
Carbon Dioxide - 0.04%
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Two kinds of Chemical Changes
Photodissociation and Photoionization
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For a Chemical Change to occur (2)
1. must have sufficient energy
2. atoms or molecules being bombarded must absorb these photons.
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is the rupture of chemical bond resulting iron absorption of a photon by a molecule.
Photodissociation
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occurs when a molecule in the upper atmosphere absorbs solar radiation and the absorbed energy causes an electron to be ejected from the molecule.
Photoionization
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is the key absorber of photons having wavelength ranging from 240 nm to 310 nm.
Ozone
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do not occur in nature and have been widely used as propellants in spray
Chlorofluorocarbons
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are among the most unpleasant and harmful of the common pollutant gases.
Sulfur compounds
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harmful to both human health and property.
Sulfur dioxide
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air pollution from burning of fossil fuels is the major cause of ____
Acid Rain
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Effects of Acid Rain
1. Weakens plants by washing away the protective layer
2. can change the composition of soil.
3. causes respiratory problems
4. it can deteriorate buildings.
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are group of several gases and compounds composed of nitrogen and oxygen.
Nitrogen Oxides
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The two most common and hazardous nitrogen oxides
1. Nitric oxides
2. Nitrogen oxides
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is a type of smog produced when ultraviolet light from the sun reacts with nitrogen oxides in the atmosphere.
Photochemical Smog
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is a gas that absorbs and emits radiant energy within the thermal infrared range.
Greenhouse gases
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is Earth's abundant greenhouse gases and responsible for about half of Earth's greenhouse effect.
Water Vapor
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is responsible for a third of the total warning of Earth's climate change due to human-produced greenhouse gases.
Carbon Dioxide
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is the unusually rapid increase in Earth's average surface temperature over the past century.
Global Warming
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is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time.
Climate Change
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Effects of Climate Change
1. Change will continue
2. Temperatures will continue to rise
3. Frost-free season
4. Changes in precipitation
5. Droughts
6. Hurricanes will become stronger.
7. Sea level will rise -8 feet by 2100
8. Artic likely to become ice free
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is an important branch of soil science.
Soil Chemistry
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Significance of Soil Chemistry (5)
1. Improving the availability of nutrients to plants
2. Utilize soil microbial organisms.
3. Improve physical conditions of the soil.
4. Helps to explain the basic properties of soils as they occur in nature.
5.Helps to monitor and follow rapid changes as they occur in the soil.
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What is Soil?
1. has been called the "skin of the earth"
2. has a dynamic body of natural materials capable to support vegetative cover.
3. is an environmental process that adapts, reflects, and responds to a great variety of natural and human-influenced processes.
4. an exceptional example of integration interdependence, and overlap among Earth's subsystem.
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Rock fragments and minerals that are not readily dissolve in water.
Insoluble Materials
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as dissolve in chemical being held by solution.
Soluble Materials
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comes from multiple sources. including the breaking (weathering) of underlying rocks.
Chemical Constituents
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is the process by adding nutrients and other constituents in order to meet the needs that is required in plant
Soil Fertilization
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means infiltration. includes the rate and capacity.
Soil Water
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Importance of Soil Water
1. Essential to all life on earth
2. Necessary for weathering of rocks
3. Medium of plants that are assimilated by plants.
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Soil water that adheres soil particles and soil clumps by surface tension.
Capillary Water
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evaporization of water to produce a cement layer like _____
Lime (calcium carbonate), Caliche
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found as very thin, invisible to the naked eye that is bound to the surfaces of soil particles.
Hygroscopic Water
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water that percolates down through the soil under the force of gravity
Gravitational Water
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Several Functions of Gravitational Water in Soil
1. Depleting nutrients in the soil by through-flow called ____
2. Gravitational water comes down to remove small particles (clay and silt)
3. Deposition by water in the subsoil is called ____
4. ______ - Organic compounds washed down through the soil detach and remove plant nutrients.
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open spaces between soil particles and clumps
Soil air
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soils contains humus in addition to minerals, gases, and water.
Organic Matter
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is dark, organic material that forms when a plant and animal decays.
Humus
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Importance of Humus
1. Soils that are rich in humus is workable and good capacity for water retention.
2. Helps plant extract nutrients.
3. Provide abundance food to microscopic soil organisms.
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Soil is usually due to main 3 pigments:
1. black (rich in humus, organic matter (peats), red aluminium and iron, good drainage, white (silicates and salts)
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yellow to yellow- brown soils
Poorer drainage
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Gleyed/grey/green soils
Very poor drainage/ waterlogging.
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Brown soils
associates with medium organic level
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refers to the particle sizes that make up mineral fraction of the soil.
Texture
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Importance of Texture
1. amount of water the soil can hold.
2. the rate of water movement
3. how workable and fertile the soil is.
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Soil can be classified according to the texture changes in depth
1. Uniform - same texture throughout the soil particles.
2. Texture contrast - abrupt texture change between the topsoil and subsoil.
3. Gradational - texture gradually increases down the soil particles.
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having diameters of less than 0.002 millimeters. Consists of fine particles which have less space between them, tiny gaps allows absorbs water easily, and they are able to hold water hence are suitable for the growth of plants.
Clayey soils
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between 0.002 and 0.05 millimeter. Can hold water to some extent because of its fine quality, generally found near the water, rich in nutrients, often mixed with other soils.
Silty Soils
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between 0.05 to 2.0 millimeters, has big particles that have larger spaces between them, water can easily penetrate, dry in nature, and lack much nutrients.
Sandy soils
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called agricultural soils because of their fertility and appropriate texture.
Loamy Soils
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amount of spaces that can water can pass through.
Porosity
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classifies according to form.
Structure
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gives distinctive structure.
Soil peds
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is usually found in subsurface soils that have been subject to leaching or compaction by animals or machinery. (Size - 1 to 10 mm)
Platy
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individual units are bounded by flat to rounded vertical faces. vertical cracks result from freezing and thawing and wetting and drying. (Size - 20 to 100 mm)
Prismatic
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is common in the subsoil of sodium affected soils. Very dense and it is very difficult for plants roots to penetrate. (Size - 20 to 100 mm)
Columnar
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common in subsoil but also occur in surface soils that have a high clay content. (Size - 10 to 75 mm)
Blocky
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common in the surface soils or rich grasslands and highly amended garden soils. ( Size - 1 to 5 mm)
Granular
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no units are observable in place or after the soil has been gently disturbed.
Structureless
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levels of acidity or alkalinity are measured in the pH scale of 0 to 14
Acidity and Alkalinity
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atmospheric nitrogen is a source of soil nitrogen.
Nitrogen
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easily leached out of soil by heavy rain, resulting in soil acidification.
Nitrate
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helps transfer energy from sunlight to plants, stimulates early root and plant growth.
Phosphorus
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Considered as macronutrient because of the high quantities a plants need in order to thrive.
Potassium
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is essential for development of plant growth.
Calcium
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is a key component of chlorophyll, the green coloring material of plants
Magnesium
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is a constituent of amino acids in plants proteins.
Sulfur
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comes from the breaking down of mineral deposits such as rocks and stones.
Iron
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essential for proper enzyme activity in plants
Copper
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helps with photosynthesis. Freely available in acid soils, often in toxic amounts in very acid soils.
Manganese
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helps in the production of a plant hormone responsible for stem elongation and leaf expansion
Zinc
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helps with the formation of cell walls in rapidly growing tissue.
Boron
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helps bacteria and soil organism convert nitrogen
Molybdenum
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are responsible for the degration of organic matter, but is also important for the maintenance of soil structure and sustainability of plant growth.
Microorganisms
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also responsible for carbon losses to the atmosphere through respiration and methanogenesis.
Microbial Activity
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has a central role in the soil nitrogen cycle.
Nitrification
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involves the sequential reduction of nitrate, nitrous oxide, nitric oxide, and nitrogen gas.
Denitrification
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is the ability of the soil to hold or store cations.
Cation Exchange Capacity
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Factor's Influencing CEC (3)
1. Soil type
2. Soil pH
3. Soil organic matter content
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is a measure of the CEC include the alkalinity or acidity.
Soil pH
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is the only known substance on Earth that naturally exists as a gas, liquid, and solids. 97%is in the oceans. A clear, odorless, tasteless liquid that is essential to all.
Water
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Structure of water consist of six valence electrons on the oxygen, and one each from the hydrogen atom.
Lewis Structure
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H-O-H bond angle
105
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are rather symmetric in that there are two mirror planes of symmetry, one containing all three atoms and one perpendicular to the plane. if the molecules are rotated 180 (360/2) the shape of the molecule is unpertubed.
Water molecules
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refers to the attraction of other molecules for other molecules of the same kind and water molecules
Cohesion
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is the attraction of molecules of one kind for molecules of a different kind.
Adhesion
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upward motion against gravity.
Capillary Action
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The curved surface formed by a liquid in a cylinder or tube.
Meniscus
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Water can moderate temperature because of two properties: high-specific heat and high heat of vaporization.
Water's High Specific Heat
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is the other property responsible for its ability to moderate temperature.
Water's High Heat of Evaporation
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Water is a polar molecule that has a high level of polarity and attraction to ions and other polar molecules.
Water's High Polarity
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is their ability to displace H2(g) from water. Represented by their large, negative electrode potentials.
Alkali Metals
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reacts with oxygen to form monoxides, superoxides, or peroxides.
Alkali Metals Oxides and Water
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react with water to form a basic solution.
Alkali Metal Hydrides and Water
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reacts with water vapor to form a magnesium hydroxide and hydrogen gas.
Magnesium
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is the only akaline earth metal that does not react with water.
Beryllium
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Similarly to the alkali metal oxides, alkaline earth metal hydroxide and hydrogen gas.
Alkaline Earth Metal Oxides and Water
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Types of Hard Water (2)
Temporary and Permanent
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Contains bicarbonate
Temporary hard water
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reacts with alkaline earth cations
Bicarbonate ions
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contains bicarbonate ions as well as other anions such as sulfate
Permanent Hard Water
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not very reactive with water.
Boron Family
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do not react with water
Carbon Family
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Although they react, they do not dissolve in water.
Nitrogen Family
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many group 1 and group 2 oxides react with water to form metal hydroxides.
Oxygen Family
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react with water to give their halides and hypohalides.
Halogens
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is a strong bleaching agent and is not very stable in solution
Hypochlorous Acid
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dissolves slowly in water to form a yellowish-brown solution
Bromine Liquid
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is a weak bleaching agent
Hypobromous Acid
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inert gases that do not react with water.
Noble Gases
