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Thermochemistry -- The Flow of Energy: Heat --

Thermochemistry -- The Flow of Energy: Heat --. Thermochemistry: the study of heat changes in chemical reactions Chemical potential energy: energy stored within the structural units of chemical substances. Thermochemistry -- The Flow of Energy: Heat --.

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Thermochemistry -- The Flow of Energy: Heat --

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  1. Thermochemistry-- The Flow of Energy: Heat -- Thermochemistry: the study of heat changes in chemical reactions Chemical potential energy: energy stored within the structural units of chemical substances

  2. Thermochemistry-- The Flow of Energy: Heat --

  3. Thermochemistry-- The Flow of Energy: Heat -- Law of Conservation of Energy: In any chemical or physical process, energy is neither created nor destroyed

  4. Thermochemistry-- The Flow of Energy: Heat -- The calorie • Expressed as a c (lower case) • Quantity of heat needed to raise the temperature of 1 g of pure water 1C Calorie • Expressed as a C (upper case) • Dietary Calorie • 1 Calorie = 1 kilocalorie = 1000 calories

  5. Thermochemistry-- An Intro Video --

  6. Thermochemistry-- The Flow of Energy: Heat -- Joule • SI unit of heat and energy • Raises the temperature of 1 g of pure water 0.2390C • 4.184 J = 1 cal Heat Capacity • Amount of heat needed to increase the temperature of an object exactly 1C • Will change depending on the mass and chemical composition Specific Heat Quantity of heat needed to raise the temperature of 1g of substance 1oC

  7. Thermochemistry-- The Flow of Energy: Heat -- Specific Heat Capacity Heat (q) specific heat capacity (C) Mass (m) change in temperature (T) q = mC T

  8. Thermochemistry-- The Flow of Energy: Heat -- Example: How many kilojoules of heat are absorbed when 1.00 L of water is heated from 18C to 85C? Solution: q = mCT q = 1000g x 4.18 J x 67oC g o C q = 2.8E5 J 1 KJ 1000 J = 280 KJ

  9. Thermochemistry-- The Flow of Energy: Heat -- Example: A chunk of silver has a heat capacity of 42.8 J/C. If the silver has a mass of 181 g, calculate the specific heat of silver. Solution: q = mCT 42.8 J = 181g x C x 1OC C = 0.236 J/goC

  10. Thermochemistry-- Measuring and Expressing Heat Changes -- Your Turn: The temperature of a piece of copper with a mass of 95.4 g increases from 20.0oC to 40.0oC when the metal absorbs 849 J of heat. What is the specific heat of copper? q = mCT 849 J = 95.4g x C x 23.0oC C = 0.387 J/g x oC

  11. Thermochemistry-- Measuring and Expressing Heat Changes -- Calorimeter

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