Changes in Matter Chapter 2 Section 3

Physical Change Any change that alters the form or appearance of matter but does NOT make any substance in the matter into a different substance. Examples: Sand Castles Crushing a Can Dissolving Sugar in Water

Changes of State Matter Occurs in 3 States Solid Liquid Gas These are all physical changes

Physical Change Is there a physical change when you dissolve a teaspoon of sugar in water? What could you do separate the sugar from the water? YES! Other examples of physical change: ~ Bending ~ Crushing ~ Chopping

Chemical Change Change in matter that produces one or more new substances is a chemical change (reaction). Example: What happens when you pour hydrogen peroxide on a cut it breaks down into water and oxygen gas.

Chemical Change Two or more substances can also combine to form different substances. A chemical change produces new substances with properties different from those of the original substances. What do iron metal and oxygen make when they combine? iron oxide (rust)

Law of Conservation of Mass Matter is not created or destroyed in any chemical or physical change. Mass measures the amount of matter. Atoms are not lost or gained, only rearranged.

Matter and Thermal Energy Energy is the ability to do work or cause change. Every chemical or physical change in matter includes a change in energy.

Temperature and Thermal Energy Temperature is a measure of the average energy of random motion of particles of matter. Warm air outside particles of gas have greater average energy of motion that the particles of air in a cool building. Thermal energy is the total energy of all the particles in an object.

Thermal Energy and Changes in Matter When matter changes, the most common form of energy released or absorbed is thermal energy. Melting of Ice: ENDOTHERMIC CHANGE (energy taken in by ice) Warming hands by a fire: EXOTHERMIC CHANGE (energy released by wood fire)

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