Phases of Matter

1. Phases of Matter and the Kinetic Molecular Theory (KMT) 11/1/10 1

2. Phases of Matter & the KMT • What is Matter? • matter = anything that has mass and takes up space (has volume). • YES = water, charcoal, glass, people, etc. • NO = light, sound, electricity • chemistry = the study of matter and how it changes. • matter can be broken down into categories: • element = a substance that cannot be broken down into simpler substances • YES = copper wire, charcoal, diamond • NO = water, sugar, salt, plastic • atom = the smallest particle that has the properties of an element. • compound = a substance made of atoms of more than one type of element, bound together with chemical bonds. Examples = see “NO” under element (above). 2

3. Phases of Matter & the KMT—con’t. • The KMT and Phases • kinetic theory of matter = explains the properties of matter • All matter is made of atoms and molecules that act like tiny particles. • These tiny particles are always in motion. The higher the temperature, the faster the particles move. • At the same temperature, more massive particles move slower than less massive particles. • There are three main phases (states) of matter: (Note: Plasmas don’t behave normally in chemical reactions, so we will not spend too much time on them.) 3

4. Solid Phases of Matter & the KMT—con’t. Gas Liquid Microscopic Views of Each Phase 4

5. Phase Changes • energy = the ability to change or move matter. Required to change the phases of matter from one to another. • there are six different phase changes: melting = change in phase from solid to liquid (ex: ice turning into water) evaporation = liquid to gas (ex: puddles disappearing as temps. heat up) sublimation = solid directly to gas (no liquid) (ex: ice cubes shrinking over time, dry ice) • the three phase changes listed above are endothermic because energy (in the form of heat) is absorbed into the substance during the change. Phases of Matter & the KMT—con’t. 5

6. • the other three phase changes: freezing = liquid to solid (ex: hot candle wax cooling and solidifying) condensation = gas to liquid (ex: a cold drink “sweating”) deposition = gas directly to solid (no liquid) (ex: frost forming on cold surface, like early-morning grass) • the three phase changes listed above are exothermic because energy (in the form of heat) is released from the substance during the change. • important to remember: just because energy is absorbed/released doesn’t mean the temperature of a substance changes during the phase change. In fact, it stays the same! (more on this later) Phases of Matter & the KMT—con’t. 6

7. Graphic Organizer Instructions • Choose 3 main colors: • one color for the matter you will draw in the beakers • another color for the exothermic phase change arrows • and a last color for the endothermic phase change arrows • Draw a picture representing the arrangement of particles of matter of a solid in one beaker (it doesn’t matter which one you start at). Write “Solid” on the label. • Choose another beaker and draw a picture representing the arrangement of particles of matter of a liquid in that beaker (it doesn’t matter which one you pick here either). Write “Liquid” on the beaker’s label. • Go to the remaining beaker and draw a picture representing the arrangement of particles of matter of a gas in that beaker. Write “Gas” on the beaker’s label. • Label the arrows with the correct phase changes that take place between the two phases represented in each pair of beakers. Be careful—use the correct terms! • Color all the exothermic phase change arrows the same color, including the key arrow under the title. • Color all the endothermic phase change arrows the same color, including the key arrow under the title (must be different from the exothermic arrows). • Write a description of each phase on the lines closest to the beaker you are describing. Be brief, but detailed. • Write your name, date, and period on the bottom of the page in the area provided. • Turn it in!