1 / 25

ENTHALPY

ENTHALPY. OBJECTIVES. Exothermic changes cause heat to be released to the surroundings Endothermic changes cause absorption of heat from the surroundings. A potential energy diagram can be used to show the energy pathway for a reaction.

rbland
Download Presentation

ENTHALPY

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. ENTHALPY

  2. OBJECTIVES • Exothermic changes cause heat to be released to the surroundings • Endothermic changes cause absorption of heat from the surroundings. • A potential energy diagram can be used to show the energy pathway for a reaction. • The enthalpy change is the energy difference between products and reactants.

  3. Enthalpy Diagrams Exothermic reactions energy course of reaction

  4. Energy Level Diagrams Exothermic reactions energy reactants course of reaction

  5. Energy Level Diagrams Exothermic reactions energy reactants products course of reaction

  6. Energy Level Diagrams Exothermic reactions energy given out ∆H is negative energy reactants products course of reaction

  7. Energy Level Diagrams Endothermic reactions energy course of reaction

  8. Energy Level Diagrams Endothermic reactions energy reactants course of reaction

  9. Energy Level Diagrams Endothermic reactions energy products reactants course of reaction

  10. Energy Level Diagrams Endothermic reactions energy products energy taken in ∆H is positive reactants course of reaction

  11. Summary Table

  12. Summary Table

  13. Summary Table

  14. Summary Table

  15. ∆H How much energy is given out or taken in? • Energy is needed to break chemical bonds • Energy is given out when bonds are made ∆H is the differencebetween the energy needed to break the bonds in the reactants, and the energy given out when new bonds are made in the products

  16. C H H H H O O O O

  17. C H H H H O O O O Energy absorbed to break bonds

  18. C H H H H O O O O

  19. C H H H H O O O O Energy released when new bonds are made

  20. Overall energy change = Energy released on making new bonds - Energy taken in to break old bonds

  21. Energy Level Diagrams Exothermic reactions energy methane + oxygen carbon dioxide + water course of reaction

  22. Test tube Reaction mixture

  23. EXOTHERMIC Heat given out to surroundings

  24. ENDOTHERMIC Heat taken in from surroundings

  25. TASK • Draw energy level diagrams for the following reactions: • Photosynthesis • Calcium with sulphuric acid • Dissolving ammonium nitrate

More Related