Three States of Matter For Chemistry or Physics

Performance Objective / Content StandardsContent Standards Chemistry 4a, 4b 4f, 4g; Physics 3c Students relate macroscopic properties of matter (is it solid, liquid, or gas) to its microscopic properties (kinetic energy of the molecules, random motion of molecules). Students understand how changing the temp (and pressure) of matter changes its microscopic properties and therefore changes its macroscopic properties. Students understand what a temperature of absolute zero means, and that there is no temperature lower than 0 Kelvin Students are introduced to the phase diagram as an easy way to predict the state of a given material at a particular T and P Students understand that diffusion is caused by random motion of molecules

States of Matter There are three states (phases) of matter: solid, liquid, and gas. The top picture shows the macroscopic (large scope or how we perceive it) view of the different phases. The lower picture shows the microscopic (small scope or the molecular level) view of the different phases. The behaviors on the macroscopic scale are directly related to properties of the microscopic scale. microscopic scale

Heat Energy We know from everyday experience that changing temperature can change the state of matter. The kinetic energy of the individual molecules that we saw is directly related to heat energy. The more heat energy a molecule has the faster it moves. Absolute zero is defined as the temperature at which there is no molecular movement, or where there is a lack of heat energy. Heat energy is also used to overcome intermolecular forces that hold both solids and liquids together.

Phase Diagram

Molecule Movement Add a couple drops of food coloring to the container of water in front of you. What do you observe is happening? How does what we know of liquid explain this? Diffusion can be explained through Brownian motion. Brownian motion