Physical and Chemical Changes in Metals Experiment

1. Chapter 1 Activity 3: Physical and Chemical Changes

2. What Happened in Activity 3? Solid Aluminum was added to a solution of Copper (II) chloride Al(s) + CuCl2(aq) → ? Name a physical change that occurred??? How do you know it was a physical change??? Name a chemical change that occurred???? How do you know it was a chemical change???

3. Activity Series of Metals Decreasing Activity Li K Ba Sr Ca Na Mg Al Mn ZnAl(s) + CuCl2(aq) → AlCl3(aq) + Cu(s) Fe Cd Co Ni Sn Pb HCu Ag Hg Au

4. What do you see?

5. Law of Conservation of Matter Matter can not be created or destroyed! Matter can only change forms!

6. Physical change The material itself is the same before and after the change. The change can usually be “undone.” Ice melting: an example of a physical change.

7. Physical Change You still have bronze! Melting bronze into a liquid

8. Physical Change Ripping Paper But this one can’t be undone so easily.

9. Origami The form/shape may change, but you still have paper

10. Cracking an Egg Beating an Egg Another example of an irreversible physical change.

11. Ghost Crystals (crosslinked polyacrylamide) + water Physical change!! Given time the water will evaporate away and leave the crystals

12. Sodium Polyacrylate Theses crystals are found in the "super absorbent layer" in most disposable diapers. If left to dry long enough, it would return to its original state or appearance. It can absorb 200 to 300 times its weight in tap water

13. Physical Change Review • Only the state of matter changes • All Phase changes are physical changes (Solid---Liquid---Gas)! • NO new substances are formed! • Not all physical changes are reversible (crushing a rock).

14. Chemical Change The substances present at the beginning of the change are not present at the end; new substances are formed. The change cannot be “undone.” A nail rusting: an example of chemical change.

15. Raw Egg Fried Egg COOKING

16. Chemical Change! The proteins in the egg have changed! The cooked egg cannot change back to a raw egg.

18. Chemical Reaction!Your body chemically reacts with the food you eat to make nutrients and energy!

19. Burning

20. Chemical Change! Rust is a new substance! (color change) Car with rust =

21. PHOTOSYNTHESIS 6 CO2 + 6 H2O → 6(CH2O) + 6 O2 sugar

22. Evidence of a Chemical Change • Color Change • Bubbling (formation of a gas) • Light given off • Temperature change • Precipitate formed. • Sound

23. Chemical Reaction!Formation of a Precipitate lead iodide (PbI2), forms from the mixture of two clear liquids, potassium iodide (KI) and lead nitrate (Pb(NO3)2).

24. Chemical Change Review • A chemical reaction occurs • New substance(s) are formed with NEW properties • It can not be reversed!

27. Physical vs. Chemical • physical • chemical • physical • physical • chemical • Examples: • melting point • flammable • density • magnetic • tarnishes in air

28. Physical vs. Chemical • http://vital.cs.ohiou.edu/steamwebsite/downloads/ChangeLab.swf • http://www.quia.com/quiz/303980.html

29. Yellow & BlueSwitcheroo

30. Yellow & BlueSwitcheroo Oscillating Reaction Chemical! Color Change indicates the chemical properties of the indicator were changed! New product formed! Can’t be reversed!

31. Pour a Rainbow

32. Acids to a Base Reactions Color change & Polymerization A Chemical Change Occurs!! We have now made our own slime!

33. Old Foamy

34. Old Foamy

35. Chemical Change Old Foamy Hydrogen Peroxide & Sodium Iodide Solution With Dishwashing Detergent New product formed! Can’t be reversed!

36. Whoosh Bottle

37. Chemical Change Exothermic Reaction: O2 + Combustion CO2 & H2O Color & Heat released New product formed! Can’t be reversed!