Exploring Physical and Chemical Changes in Cooking with Chemistry

1. Physical vs. Chemical Changes

2. Warm-up 2 January 2020 From the “Cooking with Chemistry” activity, describe how did you use phase change to complete the final task of separating the salt from the solution? http://whatscookingamerica.net/Foto4/BoilingWater.bmp

3. Standard 2 January 2020 5.a. I know reactant atoms and molecules interact to form products with different chemical properties.

5. What’s the Difference? • Matter can change • Examples: Freeze, cut, burn, etc. • 2 types of changes • Physical changes • Chemical changes

6. Physical Property • Characteristic of matter that does not change the substance (using senses)

7. Physical Changes • Matter changes form WITHOUT becoming something new • You start and end with same thing (see below) • Examples: cutting, freezing, melting, etc.

8. Molecules in Physical Changes

9. Chemical Property • Describes matter on its ability to change into new matter • Flammability: ability of substance to burn • Reactivity: ability of substance to change into new substance

10. Chemical Changes • Matter changes, becomes NEW substance • Start and end with different things • Usually irreversible (can’t change back) • Examples: burning, rusting, milk going sour

12. Physical Size Shape Texture Chemical Temperature Color Bubbles/fizzing Smoke Smell Signs of Change

13. Chemical Change = _________________ In chemical changes, atoms and molecules re-arrange to form new substances.

14. The atoms arrange to make a new substance Molecules in Chemical Changes

15. Products: the resulting solutions in a reaction Mixing Things Up: Chemical Change Demos Observations of Reactants: Chemical Change = Reaction • Observations during the demonstration: • Reactants: starting solutions in a reaction

16. Products: the resulting solutions in a reaction Chemical Change = Reaction • Reactants: starting solutions in a reaction

17. Products: the resulting solutions in a reaction Chemical Change = Reaction Chemical reactions have formulas just like molecules and compounds. As a class, we will write the chemical equation below and label the reactants and the products. Chemical Formula In words • Reactants: starting solutions in a reaction

18. Chemical Reaction Demo • NaHCO3 NaOOCCH3 + HOOCCH3 + H2O + CO2 Sodium Bicarbonate and Acetic Acid Sodium Acetate, water, and carbon dioxide

19. Products: the resulting solutions in a reaction Chemical Change = Reaction Summary: • How can you tell if a chemical reaction happened? • What are evidences to support that chemical reaction happened? • After a chemical reaction will it be possible to bring back the reactants to their original form (state and properties)? • How is chemical reaction related to chemical change? • Reactants: starting solutions in a reaction

20. Signs of Chemical Change Fizzing/gas formation Flash/light smoke Change in temperature Change in color Smell/odor

21. Warm-up 2 January 2020 Give an example of a physical change and a chemical change, and then describe how they are different from the other. Explain your answer in 2-3 sentences.

22. Warm-up 2 January 2020 Why is cooking/baking similar to science? Explain your answer.

23. Physical Change vs. Chemical Change

24. Products: the resulting solutions in a reaction Chemical Change = Reaction Observations: • Reactants: starting solutions in a reaction

25. Products: the resulting solutions in a reaction Chemical Change = Reaction Observations: • Reactants: starting solutions in a reaction

26. Products: the resulting solutions in a reaction Chemical Change = Reaction Observations: • Reactants: starting solutions in a reaction

27. Products: the resulting solutions in a reaction Chemical Change = Reaction Observations: • Reactants: starting solutions in a reaction

28. Products: the resulting solutions in a reaction Chemical Change = Reaction Observations: • Reactants: starting solutions in a reaction

29. Products: the resulting solutions in a reaction Chemical Change = Reaction Observations: • Reactants: starting solutions in a reaction

30. Products: the resulting solutions in a reaction Chemical Change = Reaction Observations: • Reactants: starting solutions in a reaction

31. Products: the resulting solutions in a reaction Chemical Change = Reaction Discussion/Summary: • How will you know if an object underwent a chemical or physical change? • Can changes happen outside of the science classroom or laboratory? • Reactants: starting solutions in a reaction

32. Physical Change v. Chemical Change Make a Venn Diagram to compare the 2 types of changes

33. Is it a chemical or physical change? • Sugar dissolving in tea • Chemical Change • Physical Change

34. OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

35. Correct!

36. Is it a chemical or physical change? • Logs burning • Chemical Change • Physical Change

37. OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

38. Correct!

39. Is it a chemical or physical change? • Breaking water up by separating it into hydrogen and oxygen • Chemical Change • Physical Change

40. OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

41. Correct!

42. Is it a chemical or physical change? • Cutting paper • Chemical Change • Physical Change

43. OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

44. Correct!

45. Is it a chemical or physical change? • Crushing an aspirin • Chemical Change • Physical Change

46. OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

47. Correct!

48. Is it a chemical or physical change? • Metal rusting • Chemical Change • Physical Change

49. OOPS! Did it change size, color, shape (Physical Change)? or Did it become different matter (Chemical Change)?

50. Correct!