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Heat and Energy

QUIZ ON ACIDS & BASES AT THE BEGINNING OF CLASS. TAKE A FEW MINUTES AND STUDY!! PICK UP THE TWO HANDOUTS. Heat and Energy. What is energy?. The ability to do work or produce heat. Define potential Energy. Energy due to composition- BONDS- or position. Define Kinetic Energy.

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Heat and Energy

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  1. QUIZ ON ACIDS & BASES AT THE BEGINNING OF CLASS. TAKE A FEW MINUTES AND STUDY!!PICK UP THE TWO HANDOUTS

  2. Heat and Energy

  3. What is energy? • The ability to do work or produce heat.

  4. Define potential Energy • Energy due to composition- BONDS- or position

  5. Define Kinetic Energy • Energy of motion

  6. Kinetic energy is directly related to… • Constant random motion of atoms or molecules.. • And is proportional to …. • Temperature

  7. What 3 things does the potential energy of a substance depend upon? • 1. The type of atoms in the substances • 2. Numbers and type of chemical bonds • 3. Particular way atoms are arranged

  8. State the Law of Conservation of Energy • Energy cannot be created or destroyed but can change from one form to another.

  9. Describe how octane contains chemical potential energy • Strength of stored energy in bonds between C-H

  10. What symbol is used to represent heat? • Q

  11. Define heat • The transfer of energy from warmer objects to cooler.

  12. Define calorie • The heat required to raise 1 gram of pure water 1 degree celsius

  13. What is another name for a nutritional Calorie? • Kilocalorie

  14. What is the difference between 1 nutritional Calorie and 1 calorie? • 1C = 1000c • C is a food calorie. Little c is defined as the heat required to raise 1 gram of pure water 1 degree celsius.

  15. If a food has 10,000 calories, how many Calories does it contain? • 10,000 cal x 1 Cal = 10Cal • 1000 cal

  16. What is the SI unit of heat and energy? • Joule

  17. One joule = .2390 calories • One calorie = 4.184 joules

  18. . • A fruit and oatmeal bar contains 142 nutritional Calories. Convert to calories. • 142 Calories x 1000 calories = 142,000 calorie • 1 Calorie

  19. Define specific heat • The amount of heat required to raise the temperature of 1 gram of a substance1 degree celsius.

  20. How many joules must be absorbed by each gram of water to raise the temperature of one gram of a substance one degree celsius? • 4.184 j/g°C

  21. What is the specific heat of • A. Water- 4.184 • B. Ice- 2.03 • C. Iron- .449 • D. Gold- .129

  22. What can water do because of its high specific heat? • Absorb large amounts of heat and cold.

  23. Why is it good to plant vineyards and orchards near large bodies of water? Water absorbs the temperature of the surrounding air to keep the temperature constant.

  24. Q= M x C x ∆T • Q = heat (Calorie or Joules) • M = mass (grams) • C = specific heat (j/g°C) • ∆T = change in temperature (°C)

  25. If the temperature of 34.4 g of ethanol increased from 25.0 C to 78.8 C, how much heat has been absorbed by the ethanol? (C= 2.44 j/g°C )

  26. Q= x • M= 34.4 • C= 2.44 • ∆T= (78.8 – 25.0)

  27. Q = M x C x ∆T • Q= 2.44 x 34.4 x 53.8 • Q= 4515.75 J

  28. A 155 g sample of an unknown substance was heated from 25.0 °C to 40.0 °C. In the process, the substance absorbed 5696 J of energy. What is the specific heat of the substance?

  29. Q = M x C x ∆T • Q = 5696 J • M = 155 g • C = X • ∆T = (40 °C– 25°C)

  30. Q = M x C x ∆T • 5696 J = 155 g x C x 15°C • C = 2.45 j/g°C

  31. Calorimeter • A device used to measure heat content.

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