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Physical and Chemical Properties 1. Lesson 3 September 24 th , 2010. Physical Properties of Water. All life on Earth depends on water. Our bodies are about 70 percent water. Some plants are 95 percent water. . Physical Properties of Water.
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Physical and Chemical Properties 1 Lesson 3 September 24th, 2010
Physical Properties of Water • All life on Earth depends on water. • Our bodies are about 70 percent water. • Some plants are 95 percent water.
Physical Properties of Water • A characteristic of water is that it sticks to itself, a property that is known ascohesion. • Due to cohesion, water forms beads on non-absorbent surfaces, such as glass. • Water also sticks to other substances, a property known asadhesion
Physical Properties • -A physical property describes a characteristic of a substance that can be observed or measured without changing the composition of matter. • Example: Melting Point, Boiling Point
When water freezes it expands due to a special bonding between water molecules. • Larger volume with the same mass = Less dense • This is why ice floats
Physical Change • In a physical change, the substance involved remains the same (chemically). The substance may change form or state, however. All changes of state are physical changes. • Examples: Dissolving a substance in a liquid, breaking something. • NOTE: Most physical changes can be reversed.
Observing Chemical Properties • A chemical property describes the ability of a substance to change into a new substance or substances. • In order to view a chemical property a chemical changemust occur. • Chemical change - the formation of a new substance or substances with new properties. • A chemical reaction is a process in which a chemical change occurs.
Chemical Properties 1. Combustibility is the ability of a substance to burn. In order to burn a substance requires Oxygen
Chemical Properties • Light sensitivity is a chemical property of that can cause new substances to form when light hits it.
Chemical Properties 3. Reacting with an acid is a chemical property where when acid is poured on a substance it produces a gas and bubbles.
MSIP • Work on the practice questions • Work on Questions from yesterdays note • Hand in work from last unit.