Presentation on theme: "What Happened in Activity 3? Solid Aluminum was added to a solution of Copper (II) chloride Al (s) + CuCl 2(aq) → ? Name a physical change that occurred???"— Presentation transcript:
What Happened in Activity 3? Solid Aluminum was added to a solution of Copper (II) chloride Al (s) + CuCl 2(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???
Activity Series of Metals Li K Ba Sr Ca Na Mg Al Mn Zn Al (s) + CuCl 2(aq) → AlCl 3(aq) + Cu (s) Fe Cd Co Ni Sn Pb H Cu Ag Hg Au Decreasing Activity
Law of Conservation of Matter Matter can not be created or destroyed! Matter can only change forms!
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.
Melting bronze into a liquid Physical Change You still have bronze!
Physical Change Ripping Paper But this one can’t be undone so easily.
Origami The form/shape may change, but you still have paper
Cracking an Egg Beating an Egg Another example of an irreversible physical change.
Hammering Metal Malleable: the ability to be hammered, pressed or rolled into thin sheets without breaking is a physical change. Malleability is a physical property of metals.
Ghost Crystals (crosslinked polyacrylamide) + water Physical change!! Given time the water will evaporate away and leave the crystals
Sodium Polyacrylate Theses crystals are found in the "super absorbent layer" in most disposable diapers. It can absorb 200 to 300 times its weight in tap water If left to dry long enough, it would return to its original state or appearance.
Physical Change Review 1.Only the state of matter changes 2.All Phase changes are physical changes (Solid---Liquid---Gas)! 3.NO new substances are formed! 4.Not all physical changes are reversible (crushing a rock).
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.
Car with rust = Chemical Change! Rust is a new substance! (color change)
PHOTOSYNTHESIS 6 CO 2 + 6 H 2 O → 6(CH 2 O) + 6 O 2 sugar
Evidence of a Chemical Change Color Change Bubbling (formation of a gas) Light given off Temperature change Precipitate formed.
Chemical Reaction! Formation of a Precipitate lead iodide (PbI 2 ), forms from the mixture of two clear liquids, potassium iodide (KI) and lead nitrate (Pb(NO 3 ) 2 ).
Chemical Change Review 1.A chemical reaction occurs 2.New substance(s) are formed with NEW properties 3.It can not be reversed!
Macroscopic Definition Microscopic Definition Physical Change The matter is the same. The original matter can be recovered. The particles of the substance are broken apart, and the atoms are rearranged. Chemical Change The matter is different. The old matter is no longer present. The original matter cannot be recovered. The particles of the substance are broken apart, and the atoms are rearranged into new particles, forming a new substance.
Physical vs. Chemical Examples: –melting point –flammable –density –magnetic –tarnishes in air physical chemical physical chemical