1 / 28

Domain 4

Domain 4. Energy Transformations. Radioactivity. Radioactivity is the spontaneous emission of alpha, beta, or gamma radiation from the nucleus of unstable isotopes. Isotopes are forms of the same element that differ in atomic mass (or number of neutrons).

nadine
Télécharger la présentation

Domain 4

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. Domain 4 Energy Transformations

  2. Radioactivity • Radioactivity is the spontaneous emission of alpha, beta, or gamma radiation from the nucleus of unstable isotopes. • Isotopes are forms of the same element that differ in atomic mass (or number of neutrons). • Every element has at least one isotope that is radioactive.

  3. Video Clip

  4. Half Life • Each radioactive element undergoes radioactive decay emitting particles and/or energy. • The time it takes for this decay to occur is the half-life of that element (or the time in takes for ½ the mass of the element to decay)

  5. What amount of a 100 gram sample remains after five half lives if one half life lasts 25 years?

  6. 1. Using the graph, determine the half-life of Bismuth-210. • 5 days • 10 days • 15 days • 30 days

  7. 1. Using the graph, determine the half-life of Bismuth-210. • 5 days • 10 days • 15 days • 30 days

  8. 2. A total of 125 grams of polonium - 210 remain from a sample that once contained 1000 grams. For how long did this sample decay? The half-life of polonium - 210 is 5 days.

  9. 2. A total of 125 grams of polonium - 210 remain from a sample that once contained 1000 grams. For how long did this sample decay? The half-life of polonium - 210 is 5 days.

  10. 2. A total of 125 grams of polonium - 210 remain from a sample that once contained 1000 grams. For how long did this sample decay? The half-life of polonium - 210 is 5 days.

  11. 2. A total of 125 grams of polonium - 210 remain from a sample that once contained 1000 grams. For how long did this sample decay? The half-life of polonium - 210 is 5 days.

  12. 2. A total of 125 grams of polonium - 210 remain from a sample that once contained 1000 grams. For how long did this sample decay? The half-life of polonium - 210 is 5 days.

  13. The halogen astatine is useful for the treating cancer of the thyroid gland. If a sample containing 0.1 mg is given to a person at 9:00 AM one morning, how much will remain in his body at 9:00 AM the next morning? Astatine’s half-life is 8 hours. (Completed chart on next page)

  14. The halogen astatine is useful for the treating cancer of the thyroid gland. If a sample containing 0.1 mg is given to a person at 9:00 AM one morning, how much will remain in his body at 9:00 AM the next morning? Astatine’s half-life is 8 hours.

  15. 4. After 80 minutes, 5 grams of an 80 gram sample of bismuth-214 remain. What is the half-life of bismuth-214? (Answer on next page)

  16. After 80 minutes, 5 grams of an 80 gram sample of bismuth-214 remain. What is the half-life of bismuth-214?

  17. What is the difference between fission and fusion? • Fission means to split apart. • The nuclei of certain atoms can be split apart.

  18. Fusion involves joining smaller nuclei to make a larger nucleus. • The sun uses nuclear fusion of hydrogen atoms into helium atoms.

  19. II. Energy • Potential energy is stored energy or energy of position. Examples: Magnetic, gravity, chemical, elastic, and nuclear B. Kinetic energy is energy of motion or energy in action. Examples: light, electricity, heat, and sound Video Clip

  20. Transformation of Energy • Energy is never lost. It is used or changed into different forms. • Example: If the energy of water transforms into mechanical energy, you might "lose" some energy by creating heat energy in the form of friction. Video Clip

  21. What energy transformations are these? • Turning on a lamp electrical energy to light energy (and heat energy) Chemical energy to electrical energy Nuclear energy (fusion) to solar energy (light and heat)

  22. III. Heat Energy and Temperature • Heat is the transfer of thermal energy between two bodies that are at different temperatures. • Heat energy moves from areas of higher temperature to areas of lower temperature. • The amount of heat that a substance releases or absorbs is dependent on the mass of the material, the change in the temperature, and the nature of the material itself. Video Clip

  23. Temperature • Temperature is the amount of heat energy possessed by an object. • Temperature is not energy, but a measure of it. Heat is energy. • higher temperature = particles move faster and farther apart 4. lower temperature = particles move slower and closer together

  24. Calculating Heat Capacity • The amount of heat energy necessary to raise a given mass of a substance by a specific unit of temperature is called the specific heat. • This equation will allow you to calculate heat gained or lost. • q = c X m XT

  25. q = c X m XT q = heat (joules) c= specific heat (J/g-oC) m = mass (g) DT = change in temperature (oC)

  26. Problem1 How much heat is given off if a 250 g cup of coffee (water) cools down from 70 0C to room temperature (23 0C)? q = c X m XT q= 4.2 J/g-oC x 250 g x (23 - 70 0C) q= -49350 Joules

  27. Problem 2 How much heat energy (Joules) is required to raise the temperature of 155 g of water from 20 0C to 50 0C? q = c X m XT q = 4.2 J/g-oC x 155 g x 30 0C q = 19530 J

More Related