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Do now;

Do now; . Turn in safety lab New Seats Put Everything away. Separations; Physical or Chemical Change?. Mixture  Pure substance? Compound  Elements?. Watch and think…. What is happening to the mass? What is happening in terms of energy?. Take out the graphic organizer.

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Do now;

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  1. Do now; • Turn in safety lab • New Seats • Put Everything away

  2. Separations; Physical or Chemical Change? • Mixture  Pure substance? • Compound  Elements?

  3. Watch and think… • What is happening to the mass? • What is happening in terms of energy?

  4. Take out the graphic organizer • You will be taking notes in it as I lecture

  5. Laws of Conservation of Matter • Matter can not be created or destroyed, only converted from one form to another • Then what happened to the mass in the paper? • Became CO2 and H2O and released into the air! CO2 + H2O

  6. Conservation of Matter • If we started with 2 grams of paper and burnt it completely, what is the mass of CO2 and H2O released into the air? • 2 grams • If 40 grams of substance A reacts with 20 grams of substance B, how many grams of substance C will be formed? • 60 Grams

  7. Law of the Conservation of Energy • Energy cannot be created or destroyed by physical or chemical change, only converted from one form to another • Where did the energy come from? • Where did it go? • What is energy?

  8. What is Energy • The ability to do work (using force to move an object a distance) • 2 Types of energy • Kinetic • Potential

  9. Kinetic Energy • The energy of Motion • Anything that moves has kinetic energy

  10. Kinetic Energy; Temperature • Temperature is the measure of the average kinetic energy • Atoms, molecules and other particles are all moving and have kinetic energy • Higher the Temp, the more kinetic energy

  11. Kinetic Energy; Temperature Scales; • Celsius; Based on the freezing and boiling points of water • 0 = freezing • 100 = boiling

  12. Kinetic Energy; Temperature Scales; • *Kelvin; Reset the Celsius scale so that there were no negative numbers • 1 kelvin increase = 1 degree C increase • 0 degrees kelvin = -273 degrees C • At 0 kelvins EVERYTHING STOPS MOVING!!

  13. Converting from Celsius to Kelvin • Freezing point of water • 0 celsius K? • 273 kelvin • Boiling Point of water • 100 Celsius  K? • 373 Kelvin • 293 kelvin  Celsius? • 20 degrees celsius • 35 Celsius  Kelvin? • 308

  14. Potential Energy • Stored Energy • Isn’t doing work right now but has the ability to if released • This climber has a lot of potential energy…she’s so high up!

  15. Potential Energy • Food has potential energy (that’s why we need to eat it!) • Stored in the chemical bonds in the molecules that make up the food

  16. Potential Energy • Coiled springs • Batteries • Objects at a height • Magnetism…

  17. Potential Energy: Measurement • Can not be directly measured • Must be converted to Kinetic energy and measured using a calorimeter • Units: Joule (or Kilojoule)

  18. Understanding check;‘What’s my rule?’ A • A boulder resting at the top of a hill • A pulled back bow B • A comet plummeting towards earth • An arrow flying through the air

  19. Back to the paper… • Did it absorb or release energy? • Where did the energy come from? • Where did the energy go? • How much energy was released in the reaction?

  20. Heat of Reaction (ΔH) • Δ= change (Δt would be change in time…) • H = heat • Heat always flows from where its hot to where its not

  21. Heat of reaction ΔH • During a reaction, energy can change from potential to kinetic or vice versa • We have specific vocabulary to describe each • Exothermic and Endothermic

  22. Exothermic • Exothermic • Exo = outside • Therm= energy/heat • Energy is being released to the outside environment • What would happen to the temperature of the outside environment • Increase

  23. Exothermic • Heat is being lost…so would ΔH be positive or negative? - ΔH

  24. Exothermic - ΔH • Examples; • Burning paper • Heat pack

  25. Endothermic • Endo = internal/inside • Therm= energy/heat • Heat is flowing from the outside  in • What would happen to the temperature of the outside? • It would decrease

  26. Endothermic • Energy is being gained, so would ΔH be positive or negative? + ΔH

  27. Endothermic + ΔH • Examples: • Cold packs • Melting ice (the ice is absorbing the heat) • Cooking an egg

  28. Put simply… • Potential energy  Kinetic energy = Exothermic • Negative ∆H • Kinetic Energy  Potential Energy = Endothermic • Positive ∆H

  29. What’s my rule? • Battery • Stretched rubber band • Food • Someone at the top of the stairs • A projectile flying through the air • A spinning yo-yo • Someone falling down the stairs

  30. What’s my rule? • A camp fire burning • Thermite reaction • An instant cold pack • Food cooking Sort; Freezing Water, Evaporating water

  31. Practice • A reaction occurs where the reactants have 70kJ of energy and the products have 50kJ. • Was this reaction exothermic or endothermic? • Positive or Negative ΔH? • If this occurred in water would the temperature increase or decrease? • What is the change in energy for this reaction?

  32. Topic 2: Energy Graphic Organizer • Lets take a look…

  33. Do now; • P 13-14 of the homework packet (and anything before it that may not be finished) • Read p8-10 in the notes packet and fill in Topic 3 graphic organizer

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