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Unit 1
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Energy is the ability to do work or produce heat Thermodynamics is the production of heat
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Molecules and atoms that make up all substances are constantly in motion- this motion is called kinetic energy Thermal energy is related to ‘kinetic energy’ Molecular motion increase as temperature increases? Demo. of thermal energy- Demo. of thermal energy Rub hands together
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Heat is also the flow of energy (always from a hotter substance to a colder one) Example- hold an ice cube in your hand- what happens? Heat from your hand is transferred to the ice cube, which then melts Spraying water on crops to prevent frost
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First Law: Energy is never created nor destroyed, it only changes form Ex- when gas is burned in your car, bond energy is converted into kinetic energy (moving pistons) and heat Chemical reactions typically involve potential energy being converted into kinetic energy
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Heat- is the amount of kinetic energy in a sample of matter Flows from warmer to cooler objects Unit of heat is the Joule (J) FYI- one joule of energy is equal to the amount of energy used by a 100W bulb for 0.01 s An ordinary paper match burns about 1,000 J Another unit is the calorie (cal)
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Temperature is a measure of the average kinetic energy Units are in degrees celsius ( o C) or in Kelvins (K) To convert between o C and K: o C= 273-K; K= o C+273 Assignment: converting Kelvin to celsius
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Lab: Purpose: understand the relationship between kinetic energy and temperature and potential and kinetic energy during phase changes Phase changes Phase changes Heating curve of water Heating curve of water
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In any substance, all of the atoms are in constant motion However, not all molecules will have the same energy- some will be moving fast, some slow and some in between If we were to graph this it would be a bell graph
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http://www.saskschools.ca/curr_content/chem 30_05/1_energy/energy1_4.htm http://www.saskschools.ca/curr_content/chem 30_05/1_energy/energy1_4.htm http://www.online.bcelearner.ca/file.php/11/co urse_material/unit1/U01L06.htm - for analogy http://www.online.bcelearner.ca/file.php/11/co urse_material/unit1/U01L06.htm
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Something to think about: What has more heat energy an iceberg or a cup of boiling water? An iceberg because there are many more molecules in an iceberg than a cup of water; heat is the TOTAL kinetic energy therefore more molecules means more energy
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