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Thursday 2-21-13. WU List 3 physical properties of a tree. List 2 chemical properties of a tree. Go over Force & Motion CBA Physical/Chemical properties & changes Worksheet. Physical Properties of a tree. Solid, hard, with rings indicating age Density is less than water (floats)
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Thursday 2-21-13 • WU • List 3 physical properties of a tree. • List 2 chemical properties of a tree. • Go over Force & Motion CBA • Physical/Chemical properties & changes • Worksheet
Physical Properties of a tree • Solid, hard, with rings indicating age • Density is less than water (floats) • Brown trunk, green leaves, opaque • Size & shape • Nonconductor, nonmetal • Not malleable or ductile
Chemical Properties of a tree • Ability to: • Photosynthesis • Flammable • Rot, Decay • Grow
Physical Properties • Quality that can be observed or measured without changing chemical composition • Color, odor, taste, texture, state • melting point, boiling point, solubility, conductivity, density, malleability, ductility,magnetism
Chemical Properties • Ability of a substance to react & form a new substance. • Oxidation – “react with oxygen” • Flammability • Corrosion –breakdown of a metal • Rusting – occurs on iron • Tarnish – dark spots on silver colored metals • Decay / rotting / fermentation / growth • Photosynthesis/Respiration
Photosynthesis • Carbon Dioxide + Water Glucose + Oxygen • CO2 + H2O C6H12O6 + O2 Respiration • Glucose + Oxygen Carbon Dioxide + Water C6H12O6 + O2 CO2 + H2O
Signs of a chemical change 1. Color change due to reaction 2. Production of gas • Bubbles, smoke, change in odor 3. Change in energy due to reaction • Gets warm or cold • Emits sound • Emits light 4. Loss of identity • New & different physical & chemical properties form
Physical Changes • Keeps same chemical composition • Mixing or dissolving (Changing shape or size) • Solution – one substance dissolved in another • Alloy = 2 metals that were mixed when in liquid state, then allowed to harden • Brass, Bronze, Steel • Phase changes • Melting, freezing, evaporating, condensing, sublimating