States of Matter Review Ch. 3

States of Matter Solid Liquid Gas Plasma These are PHYSICAL states of matter – the matter/molecules and atoms are not changing, just their level of ENERGY and temperature.

What is temperature? The AVERAGE kinetic energy (energy of motion) of the molecules or atoms in a sample of matter. = sum of energy of all atoms and molecules number of atoms and molecules

Solids Particles close together; cannot change position, so the volume and shape remain constant; only vibrating movement Liquids Particles still close together; can move around and slide over each other; volume stays constant, but liquids take the shape of the container

Gases Particles farther apart; higher energy, moving around and bumping into each other; spread out around whatever space given so volume changes, as well as shape Plasma Similar to a gas, plasma particles are free-moving, but these are in a higher energy state and some become electrically charged which makes this phase different

Changing Phases Vocab

Freezing – changing from a liquid to a solid Melting – changing from a solid to a liquid Freezing/Melting Point – the TEMPERATURE at which freezing or melting occurs Vaporizing – changing from a liquid to a gas Condensing – changing from a gas to a liquid Boiling Point – the TEMPERATURE at which vaporizing or condensing occurs

How is evaporation different from vaporization? Evaporation occurs on the surface of a liquid, when those molecules acquire enough energy to change phase; doesn’t have to be at the boiling temperature Vaporization occurs when the substance is at its boiling temperature, and the phase change is occurring with all of the particles

Thermal Expansion/Contraction Solids at warmer temperatures have particles with more energy; the particles then move around a bit more – so they take up a little more space. Examples???

It takes a change in energy for a phase change to occur: Heat of Fusion the amount of energy that needs to be added or taken away for melting/freezing; this is different for different substances Heat of Vaporization the amount of energy that needs to be added or taken away for vaporization/condensation

Heat Calculations Specific heat: The specific heat is the amount of energy per unit mass required to raise the temperature of a substance by one degree Celsius. The specific heat of water is 1 calorie/gram °C = 4.186 joule/gram °C which is higher than any other common substance. As a result, water plays a very important role in temperature regulation. The specific heat per gram for water is much higher than that for a metal.