420 likes | 639 Views
What’s the MATTER: Classify Changes of Matter. Matter, Classify Changes of Matter At the conclusion of our time together, you should be able to:. Characterize various changes of matter Recognize that a change of state in matter is a physical change. Interesting Signs:.
E N D
Matter, Classify Changes of Matter At the conclusion of our time together, you should be able to: Characterize various changes of matter Recognize that a change of state in matter is a physical change
Physical Change Physical • A change in matter from one form to another without changing its chemical properties • (most can be reversed) • No change in atoms/molecules
Physical Change • Examples = • Change in state or phase change • Dissolving • Compressing • Light emission/absorption • Electrons passing through metals
Physical Change More Examples = • boiling of a liquid • melting of a solid • dissolving a solid in a liquid to give a homogeneous mixture • making a solution
2 1 Chemical Change Chemical • Bonds are made / broken • Change in oxidation states Li +1 Cl-1 Cl-1
Examples of Chemical Change • Chemical change or chemical reaction — transformation of one or more atoms or molecules into one or more different molecules. • Burning hydrogen (H2) in oxygen (O2) gives H2O.
Sure Signs of a Chemical Change“Chemists Get Practice Trying Labs” • Color Change • Gas Produced (not from boiling!) • Precipitate – a solid formed by mixing two liquids together • Temperature Change • Light
Remember the Law of Conservation of Mass • In a physical change or a chemical reaction, mass is neither created or destroyed (Antoine Lavoisier)
Matter, Classify Changes of Matter Let’s see if you can: Characterize various changes of matter Recognize that a change of state in matter is a physical change
Physical vs. Chemical Change • physical • chemical • physical • physical • chemical • Examples: • melting • flame produced • paper cut • dissolving salt in water • tarnishes in air
Physical vs. Chemical Change • chemical • physical • chemical • physical • physical • Examples: • rusting iron • mixing mud and water • burning a log • freezing water • grinding spices
A difference between physical change and chemical change is that • chemical change involves energy while physical change does not. • physical change involves energy while chemical change does not. • different kinds of molecules are present after a physical change but not after a chemical change. • different kinds of molecules are present after a chemical change but not after a physical change
In making a pizza, which process involves a chemical change? Mixing spices for the sauce Slicing pepperoni for the topping Spreading cheese on the pizza Baking the dough to form the crust
All You Really Need To Know You Can Learn From Noah's Ark • Remember that the ark was built by amateurs; the Titanic was built by professionals. • Remember that woodpeckers inside are a larger threat than the storm outside.
Matter, Properties of MatterAt the conclusion of our time together, you should be able to: Explain the difference between the extensive and intensive properties and other types of properties Distinguish between a physical property and chemical property
The Nature of Matter Chemists are interested in the nature of matter and how this is related to its atoms and molecules. Gold Mercury
Chemistry & Matter • We can explore the MACROSCOPIC world — what we can see — • to understand the PARTICULATE worlds we cannot see. • We write SYMBOLS to describe these worlds.
A Chemist’s View Macroscopic 2 H2(g) + O2 (g) --> 2 H2O(g) Symbolic Particulate
Properties of Matter • 2 Types: • Extensive – depend on the amount of the sample • Always involves a number with unit • Examples = volume mass length
Properties of Matter (cont.) • Intensive – does not depend on the amount of the sample • Usually does not involve a number • Examples = density melting, boiling point malleability ductility color odor
Properties • Every substance has a unique set of properties (characteristics that identify that substance) • Physical Properties- • Properties that can be measured without changing the identity and composition of the substance
Physical Property Examples- • Color • Odor • Density • Melting Point • Boiling Point • Hardness • Solubility
List Some Physical Properties of: Graphite — this layer structure of carbon atoms reflects its physical properties.
Chemical Properties • Properties that describe the way a substance may change to form other substances • Only observed when a chemical reaction takes place
Chemical Property Examples • Combustible • Reactive with water or acid • Flammable • Corrosive • Decomposes in air
Physical vs. Chemical Properties • Physical Properties- • Properties that can be measured without changing the identity and composition of the substance • Chemical Properties- • Properties that can be measured by changing the identity and composition of the substance
Matter, Properties of MatterLet’s see if you can: Explain the difference between the extensive and intensive properties and other types of properties Distinguish between a physical property and chemical property
Properties of Matter • 2 Types: • Extensive – • depends on the amount of the sample • Intensive – • does not depend on the amount of the sample
Physical vs. Chemical Properties • Physical Properties- • Properties that can be measured without changing the identity and composition of the substance • Chemical Properties- • Properties that can be measured by changing the identity and composition of the substance
Physical vs. Chemical Property • physical • chemical • physical • physical • chemical • Examples: • melts at 55oF • flammable • will tear easily • will dissolve in water • will tarnish
Physical vs. Chemical Properties • chemical • physical • chemical • physical • physical • Examples: • will rust • mixture can be separated by boiling • burns • freezes at -20oC • can be crushed
Familiar Saying A rotating lithoidal fragment never accrues lichen. A rolling stone gathers no moss!!