WHAT IS MATTER?
• Objects that take up space and have mass are called matter.
• Everything around you is made up of matter.
STATES OF MATTER
• Most matter on earth can exist in three states.
• Solid- particles are packed together and cannot move.
• Liquid- particles are close together but they are not held together as tight as in q solid. Particles can move and slide past each other.
• Gas- particles are moving so fast that they don’t even stay close together. Gases expand to fill all the space available.
• Solid- has a definite shape and volume
• Liquid- no definite shape but has definite volume. Takes the shape of the container it is in.
• Gas- Has no definite shape or volume
PHASE CHANGES
• Matter can change from one state to another when thermal energy is absorbed or released.
SOLID-LIQUID CHANGES OF STATE
• Melting: The change of state from a solid to a liquid. Melting occurs when a solid absorbs thermal energy.
• Melting point: Temperature at which solid becomes a liquid.
• Freezing: The change of state from a liquid to a solid. Freezing occurs when matter releases thermal energy.
• Freezing point: The temperature at which liquid becomes a solid.
LIQUID-GAS CHANGES OF STATE
• Vaporization- process in which matter changes from a liquid to a gas.
• Evaporation- vaporization taking place at the surface of a liquid.
• Boiling: vaporization taking place below the surface of a liquid.
• Boiling point- Temperature at which a liquid becomes a gas.
-Outward observable characteristics of matter, which include:
-color -size/shape
-smell -texture
-mass -weight
-volume -density
Physical properties:
Chemical properties:
- How matter changes into other new matter
- Flammability: ability of an object to burn.
- Reactivity: ability to react with other matter.
PHYSICAL CHANGES AND
CHEMICAL CHANGES
PHYSICAL CHANGES
• A physical change does not produce a new substance. Changes in state or phase (melting, freezing, vaporization, condensation, sublimation) are physical changes. Examples of physical changes include crushing a can, melting an ice cube, and breaking a bottle.
CHEMICAL CHANGES
• Chemical changes take place on the molecular level (when the molecules change). A chemical change produces a new substance. Examples of chemical changes include combustion (burning), cooking an egg, and rusting of an iron pan
How to Tell Chemical & Physical Changes Apart
• A chemical change makes a substance that wasn't there before. There may be clues that a chemical reaction took place, such as light, heat, color change, gas production, odor, or sound. The starting and ending materials of a physical change are the same, even though they may look different.