Exam Review
Exam Outline 35 Multiple Choice > 33 Chem 2 Weather 20 Fill in Blanx Definitions: compare El Nino / La nina OR heat sink / heat capacity Long Answer: chemistry + weather ex. Water cycle diagram OR earth’s atmospheric layers diagram OR Prevailing winds, jet stream, and trade winds. 1. - Convection: Occurs when the atoms in a fluid physically circulate to transfer their energy vertically. Usually occurs when there are different temperature gradients in the fluid. - Advection: Usually associated with convection, atoms in a fluid circulate to transfer their energy horizontally. - Conduction: Energy in a solid is transferred from atom to atom by collision. Metals tend to be very good conductors, while other substances such as wood and rocks are not. - Components of the spectrum: Radio waves, microwaves, ultra-violet rays, x-rays, gamma rays, visible light, infrared light. - Transpiration: Water is expelled from plants through the leaves as a vapour. - Sublimation: The process wherein a solid changes directly into a gas, without first turning into a liquid. - Evaporation: Water changing from a liquid to a gaseous state called water vapor. - Precipitation: All liquid and solid water particles that fall from the air to the ground. It includes rain, snow, drizzle, and hail. - Condensation: Occurs when water vapor is cooled enough to revert to a liquid form. In the atmosphere, precipitation is caused by the condensation of water vapor which has evaporated from the surface. - Hydrosphere: All of the water on or around the earth’s surface in every state (water, water vapor, ice). - Atmosphere: The gaseous layers surrounding the earth. The atmosphere is essential to all life on earth. Other planets in our solar system have atmospheres, but none that can sustain human life. - Troposphere: The layer closest to the earth’s surface, where all of the weather takes place. The troposphere ends about 16 km from the surface. - Tropopause: The upper boundary of the troposphere. Warm air rising spreads out and begins to descend when it hits this layer. - Stratosphere: The layer of the atmosphere between the troposphere and the mesosphere located from 17-50 km above the earth’s surface. The ozone layer is located in this level. - Ozone Layer: A layer of ozone gas (O3) in the atmosphere located about 20 km above the earth’s surface. This layer is responsible for filtering out much of the harmful ultraviolet rays from the sun, making life on earth possible. - Atmospheric Pressure: The pressure exerted by the air on the earth. This weight is measured in kilopascals (kPa). The atmospheric pressure of a region can be affected by air systems called high or low pressure systems. - Temperature Gradient: The change in temperature over a particular vertical distance (altitude). - Isobar: A line on a weather map connecting areas of equal barometric pressure. These lines whill form a “circular” pattern around high and low pressure areas. - Pressure Gradient: A measure of the amount which the atmospheric pressure changes over a certain distance. Pressure gradients can be visualized by looking at the isobars on a weather map and seeing how close or how far apart the isobars are. Note: pressure gradients can be horizontal as described above or vertical. - Tropic of Cancer: A line of latitude located 23.5 degrees north of the equator. The sun is directly overhead this region during the northern hemisphere’s winter solstice. - Tropic of Capricorn: : A line of latitude located 23.5 degrees south of the equator. The sun is directly overhead this region during the northern hemisphere’s summer solstice. - Latitude: Imaginary lines running horizontally around the earth. Lines of latitude measure distance from north to south. One degree of latitude is 110 km (69 miles). The equator is 0° latitude, all lines north of the equator are degrees north latitude (°N), and all lines south of the equator are degrees south latitude (°S). - Longitude: Imaginary vertical lines drawn from the north to south poles of the earth. 0° Longitude is called the Prime Meridian, which is centered on Greenwich, England. - Radiation: A way which energy travels without a medium (particles). This is the way energy from the sun reaches earth, as there are very few particles in space for energy to travel through. - Convection: Occurs when the atoms in a fluid physically circulate to transfer their energy vertically. Usually occurs when there are different temperature gradients in the fluid - Advection: Usually associated with convection, atoms in a fluid circulate to transfer their energy horizontally. - Conduction: Energy in a solid is transferred from atom to atom by collision. Metals tend to be very good conductors, while other substances such as wood and rocks are not. - Solar radiation: The energy given out by the sun (in the form of radiation). The energy includes visible light, x-rays, ultraviolet light, infrared light, and radio waves. - Albedo: The albedo of a substance is a measurement of the percentage of light an object reflects. It is the amount of light reflected by the substance compared to the amount of light shone upon it. The highest albedo an object can have is 1, when 100% of the light shone on it is reflected back. The lowest is 0, when the substance absorbs all of the light. - Heat capacity: The measure of how much heat (energy) a substance requires to increase its temperature. Conversely, it is a measure of how much heat (energy) an object releases as its temperature falls. Water is a high heat capacity and so it will absorb a lot of heat (energy) when it warms up. Air on the other hand has a low heat capacity. It does not hold much heat energy. Little is required to heat it up and it loses it quickly. - Heat Sink: Any object or material that absorbs energy and becomes warmer (i.e. it holds the energy). The atmosphere and oceans are heat sinks. The oceans (and lakes) in particular are huge heat sinks. They have absorbed and hold tremendous amounts of energy which they can release back is cooling occurs. - Coriolis Effect: Caused by the earth’s rotation, the Coriolis Effect occurs when an air mass moves towards the equator from the poles. As the air moves it is deflected to the right if coming from the north, or the left if coming from the south. - Trade Winds: Winds created by the mid-latitude convection currents (30° latitude). These winds move from the high pressure area at 30° latitude towards the low pressure area at the equator and twist east because of the Coriolis Effect. - Mid-latitude Westerlies: Wind coming from the 30° latitude convection currents, and heading towards the low pressure system at 60° latitude, twisting west as it nears. - Jet stream: These are high speed winds in the upper troposphere. They are often found in the mid-latitudes. Note: these winds blow in the opposite direction to the surface winds. - Kilopascal (kPa): The internationally recognized unit for measuring atmospheric pressure. Normal atmospheric pressure is 101.3 kPa. (Note: 100 kPa is about the same as the pressure under an average students foot.) - Aneroid Barometer: A device used for measuring atmospheric pressure. It consists of a sealed metal container which has expandable sides. As the atmospheric pressure changes the sides will expand and contract moving a pointer. - Greenhouse Effect: The process by which gases build up energy (heat) in the atmosphere by absorbing long-wavelength (infrared) radiation from the earth’s surface. Carbon dioxide, methane, etc are greenhouse gases. - El Niño: Caused by warmer than usual ocean temperatures. As a result of an accumulation of water on the western shores, this “pile-up_ of water spreads eastward causing ocean currents to reverse, which in turn reverses the wind currents. It has large effects on agriculture, fishing, and local weather especially in South America. - La Niña: Caused by cooler then usual ocean temperatures. Causes increased precipitation in Australia and Indonesia, Peru temperatures drop, normal weather conditions are amplified during La Niña. 2. 100% of our energy comes from the sun. Sun >>>Radiation>>>Earth *> Reflected and Absorbed: the surface of earth warms up through 1. Conduction (transfer of energy in particles like soil, rocks) and 2. Convection and Advection: fluids like oceans, lakes, etc. Re: Conduction: particles bashing into each other Convection / Advection: through a fluid 1. Gas 2. Water Light from the sun: 1. Ultra violet 2. Visible 3. Infra red 3. The earth loses on average as much energy as it absorbs. The energy absorbed in transformed to other types of radiation and released back into space. Infra red is radiated back, we want to keep the visible light. The average surface temperature of the earth is about 15 C. This temperature is critical for plants to survive as well as animals and humans. 4. If something were to change the rate at which earth absorbs energy, the average temperature could change, negatively influencing the environment. Pollutants like aresol can that spray ozone. Greenhouse effect is changing the temperature. Greece –25 C!! These aerosol sprays are destroying the ozone layer and increasing the amount of radiation the earth absorbs. 5. Oceans, lakes, rivers, atmospheric vapor, snow, glaciers, underground water. 6. Radiant energy warms the water, land, and air. Water evaporates, sublimates, or transpires through plants into invisible water vapor. The water cools, condenses and falls in the form of precipitation. 7. See “Atmospheric Layers” 8. 101.3 kPa is the normal air pressure. It goes downward with an increase in altitude. 9. 10. The earth is tilted at 23.5 degrees. When the northern hemisphere is angled towards the sun, it is summer. When it is angled away, winter. This is due to the fact that the rays have to cover more area and go through more atmosphere when the earth is tilted away. 11. Albedo is a measurement of the % of light that an object reflects. High albedo means a high amount of the light is reflected. Ice has a high albedo compared to dirt. Dirty snow, sea water, ice caps: Lowest to Highest. Albedo = The amount reflected _________________ total amount received Absorbs 25%>>>25/100>>>reflects>>>75/100>>>albedo = 0.75 0.65 albedo = 65% reflected. 12. 103.1 kPa = 103100 Pa 13. Science 20S Chemical Reactions 1. 1. Chemical Reaction: (chemistry) a process in which one or more substances are changed into others; "there was a chemical reaction of the lime with the ground water" A process in which new substances with new properties are formed. 2. Law of Conservation of Mass: In a chemical reaction, the total mass of the reactants is always equal to the total mass of the products. 3. Chemical Reactant: A chemical reactant is one of the substances, which undergoes a chemical change. “The substances which undergo the chemical change.” 4. Chemical Product: The substances that result from a chemical reaction are called chemical products. 5. Subscript: The 2 in H2O is a subscript. It tells you how many hydrogen atoms there are in each water molecule. 6. Coefficient: The 2 in front of 2 H2O indicates that there are two separate water molecules. The 2 I front of the chemical formula for the molecule is the coefficient and indicates the number of molecules of that element. 7. Synthesis Reaction: In a synthesis reaction, two or more simple substances combine to form a more complex substance. The form of the reaction is always A + B = C. 8. Decomposition Reaction: In a decomposition reaction, a more complex substance breaks down into two or more simpler substances. The form of the reaction is always C = A + B. 9. Single Replacement Reaction: In a single displacement reaction, one element replaces (or displaces) another element in a compound. The form of the reaction is always AX + B = BX + A 10. Double Replacement Reactions: In double replacement reactions, elements in different compounds displace each other (or exchange places). The form of the reaction is always AX +BY = AY + BX 11. Combustion: Combustion is a chemical reaction that occurs when a substance reacts very quickly with oxygen to produce energy. (the reaction is exothermic) Ex. CH4 + O2 = CO2 + H2O + energy 12. Exothermic Reaction: a chemical reaction accompanied by the evolution of heat. Ex. C + O2 = CO2 + energy. 13. Oxidation: Looks like combustion but it does not proceed very quickly nor does it produce a lot of energy. Ex. 2Fe + O2 = 2FeO. A reaction in which the atoms in an element lose electrons and the valence of the element is correspondingly increased. The combination of a substance with oxygen. 14. Hydrocarbon: Compounds consisting of hydrogen and carbon atoms alone are called hydrocarbons. The simplest of these is natural gas or methane CH4. 15. Greenhouse Gas: The oxidization of hydrocarbons produces carbon dioxide, which is a greenhouse gas. Elevated levels of CO2 in the air cause the atmosphere to reflect heat back down, much the way windows do in a greenhouse. Gases that act similarly to CO2, in causing the greenhouse effect, are called greenhouse gases. 16. SMOG: These products: CO2, H2O, CO, C, in the “Smoke” combined with water vapor (FOG) produce hazardous SMOG which causes many health problems in the affected areas. 17. Ground-Level Ozone: Ozone near the Earth’s surface, is produced when sunlight interacts with some natural gases and emissions from industries and vehicles. Acids and Bases Elements, Periodic Table, Bonding Capacity 1. 1. Pure Substance: A substance which has unique chemical properties (i.e. always the same) and which cannot be broken down by physical means. 2. Elements: Are pure substances which cannot be broken down by chemical or physical means into other simpler substances. 3. Chemical Symbol: The chemical formula for a compound describes the components of a compounds molecules and the ratio they exist there in. 4. Compound: Pure substances which can be broken down into simpler substances by chemical means. 5. Atomic Number: Number of protons which an atom contains in it’s nucleus 6. Periodic Table: The organization of elements first created by Dmitri Mendeelev and refined by Henry Moseley. Shows atomic number, shells of electrons (rows), and valence electrons (columns). 7. Chemical Family: Elements in a particular row of the periodic table possessing similar chemical properties. Families include Alkali Metals, Alkaline Earth Metals, Chalcogens, Halogens, and Noble Gases. 8. Valence Electrons: The number of electrons in the outermost shell of an atom. 9. Electron dot diagram: a.k.a. Lewis dot diagram. Illustrates the electrons in the outer shell of an atom. Developed by Gilbert Lewis. 10. Valence (number): i.e. combining capacity. Ex. Sodium has one valence electron and a valence of +1. 11. Ion: An ion is a charged particle. Atoms which have a charge after losing or gaining electrons. 12. Ionic Bond: Is a bond of a metal and a non-metal atom by the transfer of electrons from the metal to the non-metal. The ionic bond results from the force of attraction between the oppositely charged ions. 13. Ionic Compound: Is a compound which consists of positive and negative ions held together by their electrostatic attraction. 14. Covalent Bond: A bond formed between two or more non-metal atoms sharing one or more pairs of electrons. 15. Molecular Compound: A compound made up of two atoms that share electrons. In H2O for example, H needs one electron to complete its outer shell. O needs two electrons to complete its outer shell. By sharing electrons both can achieve stability. The result is a very stable molecule. 16. Polyatomic Ion: A cluster or group of atoms bonded together covalently which tend to stay together an which carry an overall ionic charge. Ex. Hydroxide ion OH-1. These molecular ions tend to stay together and form ionic combinations of molecules. 17. Chemical Formula: The bonding rate of two or more elements. Ex. How we write out the chemical symbols when sodium bonds with chlorine. NaCl is the chemical formula. 18. Polymer: Polymers such as Kevlar are formed when tens or hundreds or smaller molecules link together to form long, thin molecules. 19. Organic Compound: Compounds that contain carbon atoms as the basic building block. They also include Hydrogen and Oxygen and are sometimes called hydrocarbons. Ex. Methane, sugar, all petroleum compounds, and natural fibers. Naturally occurring organic compounds are produced by plants using photosynthesis. 20. Synthetic Compound: a.k.a. artificially made. Compounds “built” by scientists using crude oil and natural gas as sources of hydrocarbons to produce chemical compounds which may or may not naturally occur in nature. Ex. Nylon, Kevlar 21. Ozone Layer: Ozone, O3, is an unstable, highly reactive gas. At altitudes between 10 and 15 km the concentration of this gas is such that it absorbs UV rays from the Sun. 22. UV Index: A scale that tells us how much time in the sun would cause sunburn. This index is announced each day in the summer, when the rays are the most direct. 23. CFC’s: a.k.a. chlorofluorocarbons. The biggest cause of ozone depletion is the use of CFC’s. They are man made chemicals, which are very stable so they persist in the environment for a long time. Freon, a CFC gas used in air conditioning compressors has been identified as a significant cause and its use has been curtailed in most countries. 24. SPF: Sun Protection Factor; should be appropriate to screen the harmful effects of UV radiation. Ex. 15 SPF 25. Photosynthesis: The process in green plants and certain other organisms by which carbohydrates are synthesised from carbon dioxide and water using light as an energy source. Most forms of photosynthesis release oxygen as a by-product. 26. IUPAC: International Union of Pure and Applied Chemistry. A world body of chemistry which tells us how to name compounds. Ex. Metal, then non-metal ending in the suffix “ide”. Atmospheric Layers The atmosphere consists of five main layers. 1. Troposphere: Closest to earth’s surface with an altitude of 16 km at the equator but 8 km at the poles. This is because the air at the equator is hotter, therefore takes up more space by expanding. It is responsible for most of earth’s weather patterns because it contains most of the moisture. The average temperature is –50 C. At the outer limit of the Troposphere is the Tropopause. A thin layer that separates the two. 2. Stratosphere: A dry atmospheric layer from about 12 km to 50km that contains high concentrations of ozone. The average temperature is 10 C. 3. Mesosphere: It is the middle layer. It extends from 50km to 80km, it has similar concentrations of ozone and water vapor as the stratosphere. The average temperature is –75 C. 4. Thermosphere: Absorbs the highest amount of energy in the form of electromagnetic waves from the sun making it the warmest layer at an average temperature of 30 C. It extends from 80Km to 500km. AKA Ionosphere because it contains high energy radiation from the sun, causing particles to become electrically charged ions forming auroras or Northern Lights. 5. Exosphere: The thin outermost layer of the atmosphere. There are few particles found here, they are very spread out. Often called space! Note: The Tropopause and the stratopause are very thin boundaries found between the main layers that separate them. They have similar water vapors, but contain a little more ozone than the layer just below them. Altitude: Is the height above sea level measured in meters or km. All the layers at the equator are thicker than higher latitudes because the air there is warmer, and therefore it expands covering more space than the cold air at the poles. Ozone: A gas made up of 3 oxygen (O3); in the upper atmosphere, ozone absorbs u-v rays, which are very harmful to the environment and people. Although ozone in the stratosphere is helpful, ozone near the ground is very harmful. **The atmosphere is the key component required to support LIFE** Ozone in the upper atmosphere absorbs u-v radiation, protecting us from the harmful radiation from the sun. The atmosphere is also involved in the water cycle, which supplies earth with water. The atmosphere also helps to regulate the average temperature, keeping it within a life supporting range. It also protects the earth from meteors and other objects coming down, because most of the objects vaporize due to the frictional effects they meet when entering the atmosphere. Some things to know: Endothermic = heat added to reaction. Exothermic = heat produced. Arctic Circle: 66.5 degrees North Tropic of Cancer: 23.5 degrees North Equator: 0 degrees Tropic of Capricorn: 23.5 degrees South Antarctic Circle: 66.5 degrees South Earth’s axis: 23.5 degrees Close isobars indicate a low pressure gradient. Solstice: Winter + Summer. The hours of sunlight different lengths. Summer = June 21 Winter = Dec 21. Equinox: Autumnal + Vernal (Spring). Hours are equal. Spring = March 21 Autumnal = Sept 21. Aneroid Barometer: A device used to measure atmospheric pressure. Neutralization reaction: Acid + Base >>> salt + H20 (water) Ex. Figure out the products of sulfuric acid + aluminum hydroxide and balance the equation. . . . . . . . . . . . . . . . 3(H2SO4) + 2Al(OH)3 >>> Al2(SO4)3 + 6(H2O) Coriolis Effect: The apparent change of direction of an air mass in a rotating system is called the Coriolis effect. Since the earth is rotating east to west, if an air mass moves toward us from the north, it looks like it is moving to the west. This is because the earth is moving us away from the air mass as its spinning east to west, while the air mass is moving in a straight line. If you are unsure of this effect, go to this link and download the movie. Jet Stream Formation: Jet streams are high speed winds in the upper regions of the troposphere, often around the mid-latitudes. Tend to move from West to East, and steer most weather systems. Jet streams are found at the boundaries between the Polar regions, temperate zones, and tropical zones. The jet streams cause Polar temperatures to the north and warmer temperatures south of the jet stream. El Nino: A shift in ocean currents, temps, (water becomes warmer) and atmospheric conditions in the tropical Pacific Ocean. In contrast to El Niño, La Niña (female child) refers to an anomaly of unusually cold sea surface temperatures found in the eastern tropical Pacific. La Niña occurs roughly half as often as El Niño. If your confused, go to this link and look at the animation. The atmosphere is made up of 78% Nitrogen, 21 % oxygen, and 1% other gases. Right Hand Rule: If your thumb is the north pole, the earth rotates in the direction of your curled fingers Prefixes: Mono Di Tri Tetra Penta Hexa Hepta Octa Nona Deca Differences between ionic and covalent: Ionic: - Transfer of electrons - Between a metal and a non-metal. Covalent: - Sharing electrons (octet rule) - Between two non-metals. Note: if hydrogen is written second, it is considered a non-metal and the reaction is covalent. Periodic Table: Groups are horizontal columns, and tell us the number of valence electrons. Periods are vertical columns, and tell us how many electron shells the element has. Alkali Metals, Alkaline Earth Metals, Chalcogens, Halogens, Noble Gases. Protons = Atomic # Electrons = Atomic # Neutrons = Atomic mass (the bigger one) – Atomic Number Periodic Table Must-Know Elements
Hint: Print the symbols on one page and the names on another. You can self quiz yourself that way.1-20, 24-30, 35-38, 47, 50, 53-56, 79-82 85-88 92 1.H 2.He 3. Li 4. Be 5. B 6. C 7. N 8. O 9. F 10. Ne 11. Na 12. Mg 13. Al 14. Si 15. P 16. S 17. Cl 18. Ar 19. K 20. Ca 24. Cr 25. Mn 26. Fe 27. Co 28. Ni 29. Cu 30. Zn 35.Br 36. Kr 37. Rb 38. Sr 47. Ag 50. Sn 53. I 54. Xe 55. Cs 56. Ba 79. Au 80. Hg 81. Tl 82. Pb 85. At 86. Rn 87. Fr 88. Ra 92. U Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminum Silicon Phosphorus Silicon Chlorine Argon Potassium Calcium Chromium Manganese Iron Cobalt Nickel Copper Zinc Bromine Krypton Rubidium Strontium Silver Tin Iodine Xenon Cesium Barium Gold Mercury Thallium Lead Astatine Radon Francium Radium Uranium
