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Matter : Physical vs. Chemical. Properties of Matter. Characteristics that enable us to distinguish one kind of matter from another. How can we distinguish hydrochloric acid from water?. Types of Properties. Extensive Depends on the amount of matter
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Properties of Matter • Characteristics that enable us to distinguish one kind of matter from another. • How can we distinguish hydrochloric acid from water?
Types of Properties • Extensive • Depends on the amount of matter • e.g., volume, mass, amount of energy (cal) • Intensive • Does not depend on the amount of matter • e.g., melting point, boiling point, density, conductivity
Physical Property Can be observed or measured without changing a substance’s composition. Physical & Chemical Properties
Physical Properties BoilingPoint Melting Point Color Density Malleability Conductivity Magnetism Hardness Ability to transmit light
Physical & Chemical Properties • Chemical Property • Can only be observed by changing the composition of the material • Changes its identity
Chemical Properties The ability of a substance to… Rust Decay Burn Ferment React with acid, base, or water
Properties of Water • Water expands as it freezes. (Physical) • Hydrogen peroxide, H2O2 can decompose to produce water. (Chemical) • Water boils quicker in Denver, CO than at the beach. (Physical) • When an electrical current is passed through water, elemental hydrogen and oxygen are produced. (Chemical) • Salt can dissolve in water. (Physical)
Physical Change Will change the visible appearance, without changing the composition of the material Changes that effect only physicalproperties. Does not change the composition! Physical & Chemical Changes
Physical Changes • Boil • Melt • Freeze • Distillation • Sublimation • Expand • Crush • Diffuse • Condense • Osmosis • Cut • Split • Crack Physical changes are usually reversible
Physical & Chemical Changes • Chemical Change • Changes that involve a change in the composition of the substance. • New matter is formed
Chemical Changes • Ferment • Decay/Decompose • React with acid, base, or water • Neutralize • Rust • Digest • Tarnish • Explode / Burn • Ignite • Cook Chemical Changes are usually NOT reversible
2H2O2H2 + O2 Reactants the stuff you start with • Products- what you make Arrow points from the reactants to the new products • The products will have NEW PROPERTIES different from the reactants you started with
Indicators of Chemical Change • Color Change • Gas produced • Temperature change • Light produced • Precipitate forms • Irreversibility • Not easily reversed!
Indicators of Chemical Change • Color Change • Very hard to reverse • Think about cooking an egg
Indicators of Chemical Change • Gas produced • Bubbles are produced • Careful there are examples of bubbles that are not chemical – boiling water bubbles • Physical change Water vapor starts to form inside the liquid in the form of bubbles
Indicators of Chemical Change • Temperature change • Heat given off- Exothermic • Feels hot • Feel someone after they workout they’re hot • Heat absorbed- Endothermic • Feels cool • Sweating while working out
Indicators of Chemical Change • Light produced • Striking a match flame produced • Fireworks
Indicators of Chemical Change • Precipitate forms • 2 liquids solid + liquid
Law of Conservation of Matter • In any physical or chemical change, matter is neither created nor destroyed. • During any chemical reaction, the mass of the products is always equal to the mass of the reactants
Law of Conservation of Matter • All the mass can be accounted for!! • Burning of wood results in products that appear to have less mass as ashes. • Where is the rest??