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Temperature vs. Heat Heat: The flow of energy due to a temperature difference Heat transfer occurs from the hotter substance to the cooler substance
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Thermo-Thermo-ChemistryChemistry
Time to bring on the heat!
Energy vs. TemperatureEnergy vs. Temperature
Energy: The capacity to do work.
Temperature: Temperature: A measure of A measure of the the AVERAGEAVERAGE kinetic kinetic energy of energy of particles in a particles in a sample of sample of matter.matter.
Temperature vs. HeatTemperature vs. Heat
Heat: The flow of energy due to a temperature difference
Heat transfer occurs from the hotter substance to the cooler substance
ConductionConduction• The transfer of energy as heat between particles
as they collide within a substance or between two objects in contact.
• EX: Soup warming on the stove; soup warms the bowl
ConvectionConvection• The transfer of energy by
the movement of fluids (gas or liquid) with different temperatures.
• EX: You crawl out of a smoky room because the hot smoky air rises and cool clean air sinks to the floor
RadiationRadiation• The transfer of energy by electromagnetic
waves• EX: infrared radiation, visible light, &
ultraviolet rays
Endothermic vs. ExothermicEndothermic vs. Exothermic
Endothermic: A process that ABSORBS energy.
Exothermic: A process that RELEASES energy.
Making Ice & Heat PacksMaking Ice & Heat Packs
Which salts would make a good ice pack or a good heat pack?
Calcium AcetateSodium ChlorideAmmonium NitrateAmmonium ChlorideCalcium Chloride
Make this table on the back of Make this table on the back of your note sheet!your note sheet!
Compound GetsWarmer
Gets Colder
NoChange
Calcium Acetate
Sodium Chloride
Ammonium Nitrate
Ammonium Chloride
Calcium Chloride
Heating Solid Heating Solid WaterWater
The Hot Plate is at a Constant
Temperature
Phase Change Diagram of Water
Phase Change Diagram of Water
Solid Ice Warming
Phase Change Diagram of Water
TransitionSolid/Liquid(Stays @ 0°C)
Phase Change Diagram of Water
Liquid WaterWarming
Phase Change Diagram of Water
TransitionLiquid/Gas (Steam)
(Stays @ 100°C)
Phase Change Diagram of Water
Gas Warming
James Joule’s Experiment
James Joule’s experiment involved the conversion of mechanical energy to heat (thermal) energy.
Look at all of the paddle surfaces!
They allow for a lot of
FRICTION between water
molecules!
Friction between
molecules generates
heat energy!
We can measure the temperature
increase.
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