2SolidHas a definite shape and volume. Particles that make up a solid are packed together in relatively fixed positions and are held together by strong attractive forces between them.
3LiquidHas a definite volume but an indefinite shape (it assumes the shape of its container). Particles are close together but can move past one another. They move more rapidly than in a solid. This allows them to temporarily overcome the attractive forces and allows liquid to flow
4GasHas neither a definite shape or volume. It will fill its container. Particles move very rapidly and are at great distances from each other. Attractive forces become very weak.
5Physical PropertiesCharacteristics that can be observed or measured without changing the identity of the substance. They describe the substance.Ex: Boiling point, Melting point
6Physical ChangeIt does not involve a change in the identity of the substance.Ex: Grinding, cutting, melting, boiling
7Chemical PropertiesRelates to a substance’s ability to undergo changes that transform it into different substances.Easiest to see when substances react to form new substances.Ex: Iron’s ability to rust, silver can tarnish when combined with sulfur
8Chemical Change Also known as a chemical reaction A change in which one or more substances are converted into different substances.
9Drawing of Physical Change Solid CO2 -> gaseous CO2
11DensityDensity depends on how tightly the atoms/molecules are packed together
12Gas – low densityThe molecules are far apart; therefore, lots of volume
13Liquid – higher density Molecules are closer together, so density is higher
14Solutions – higher density Water molecules have other molecules “fitting” into spaces, increasing the mass for the same volumeThis is why sugar and salt water are more dense than pure water
15Phase Changes Melting – changing from a solid to a liquid Freezing – changing from a liquid to a solidEvaporating – changing from a liquid to a gasCondensing – changing from a gas to a liquidSublimation – changing from a solid to a gasDeposition – changing from a gas to solid