1 / 10

The Flow of Energy – Heat

The Flow of Energy – Heat. Chapter 17.1. Warm Up. What happens to the heat from the lava?. Why does lava cool more quickly in water than on land?. Introduction to Thermochemistry.

candace-myers
Télécharger la présentation

The Flow of Energy – Heat

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Flow of Energy – Heat Chapter 17.1

  2. Warm Up What happens to the heat from the lava? Why does lava cool more quickly in water than on land?

  3. Introduction to Thermochemistry • Thermochemistry (or Thermodynamics) is the study of heat, energy, and temperature changes that occur during chemical reactions (One of the main courses of study in Physical Chemistry) • Law of Conservation of Energy (1st Law of Thermodynamics) – The law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant. (Whether a reaction flask or the universe

  4. Temperature vs. Heat • Temperature is the measure of the average kinetic energy of the particles in a substance • Measure using a thermometer • Rises when heat is added • Falls when heat is removed • Heat(q) is the energy that is transferred between two objects • Cannot be measured directly • Can only detect the changes caused by heat HOT COLD

  5. Thermochemical Reactions • System – reactants and products • Surroundings – the reaction container

  6. Exothermic vs. Endothermic Exothermic Endothermic Heat Heat

  7. Measuring Heat • The Joule (J) is the SI unit of heat and energy • The calorie (cal) is also used to measure heat capacity and is defined by the amount of heat needed to raise the temperature of 1g of pure water by 1C • 1 J = 0.2390 cal 1 cal = 4.184 J • NOTE: The energy contained in food is measured in Calories (Cal) = 1000 calories = 1 kcal

  8. Heat Capacity vs Specific Heat • Heat capacity is the amount of heat needed to raise the temperature of a substance by 1C J/C or J/K • Specific heat capacity (C) is the amount of heat needed to raise the temperature of one gram of a substance by 1C J/gC or J/gK

  9. Examples of specific heat capacities

  10. Cool Down Which of these pictures contains more heat? C = q / m xDT q = C x m xDT

More Related