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1、MATTER IS THE STUFF AROUND YOU Not very clear, but its true. Anything that takes up space or has a mass of any kind is matter. Everything you can touch is made of matter. If it is made of anything, that anything is matter. Everything you will learn about chemistry will all be based on how matter rea
2、cts and combines. Matter has many properties. It can have PHYSICAL properties like different densities, melting points, boiling points, freezing points, color or smells. There are also CHEMICAL properties that define matter. A good example of chemical properties is the way elements combine with each
3、 other in reactions. The big thing to remember. Matter can change in two major ways, physically and chemically. If we are to understand how matter is behaving we must understand what is happening at matters most basic level-the smallest particle of matter involved in the change (aka atoms and molecu
4、les).Matter in MotionMotion is a common characteristic of large scale samples of matter that are given suitable pushes and pulls (also known as forces). Tennis balls, automobiles, rain drops, popcorn, and dust particles in a ray of sunlight can all be easily visualized in states of motion. But we wi
5、ll learn that even large scale objects seemingly at rest are still in motion! To develop such a view we will examine the behavior of matter more closely-specifically GASES.Recall that there are three main states of matter (with a fourth state that is not too common): SOLIDS, LIQUIDS, GASES, and PLAS
6、MAS. These states can also be called “PHASES”. We already know that matter is made of combinations of elements and compounds and (according to Dalton) ultimately-ATOMS!The phase of a substance describes a physical property of matter. The key word here is physical and not chemical because matter will
7、 move from one phase to another by physical means. By adding heat or taking heat away, we change the temperature of the substance and its physical state, but the chemical composition and chemical properties of the substance stay the same (usually). Melting is a good example of a change of state. We
8、can proceed from a solid state of matter to a liquid state of matter to a gas. Depending on certain conditions (like temperature and pressure), many different types of matter can exist in all three states. The colder a sample is the more likely it is to be a solid; the hotter it is, the more likely
9、it is a gas. We will discover that PRESSURE as well as temperature can have a strong influence on the behavior of a gas.To understand states of matter and the changes of state more fully, we need to add a new theory to our knowledge. This scientific theory is known as the KINETIC MOLECULAR THEORY (K
10、MT). With any scientific theory, there must be model that can be used to explain it. The scientists model is a simple description or representation of a real system or phenomenon that can be used to study the important aspects and events. By analyzing the structure and behavior of the model, the sci
11、entist hopes to develop a clear picture of what is actually going on. In other words, the model provides a test for the original concept or idea. Models can help reveal strengths and weaknesses in any theory.As an example, lets look at a game of football. If a football coach has enough players for t
12、wo teams, the second team is used as a model for the opposing team in preparation for the next game (also known as “giving the first team a look”). The second team tries to run the same plays the opponents are likely to use in the real game. By running offensive plays against the teams first defense
13、, the model “tests” that defense. The second team is a “model”. It has the same number of players as the opposing team and it runs the same plays. The coach just hopes the opponents arent much better than the second team. Model building and theorizing are common human activities; such activities all
14、ow us to simplify and organize all of the data and information that we take in though our senses everyday of our lives. The search for patterns or regularities from our observations often leads to a theory or model that can be used to challenge our current beliefs or better understand the events aro
15、und us.Kinetic Molecular TheoryAround 1860 (after Dalton), Ludwig Boltzman and James Maxwell (from the Einstein video and electromagnetism fame with Faraday), both in different countries, each proposed a model to explain the properties of gases. Imagine a gas in a balloon-it exhibits some behaviors
16、much different than solids or liquids. Think about air pressure and how it affects our ability to breathe and what might happen when a planes door opens at 35, 000 feet versus sea level. The word kinetic comes from the Greek, “to move”, the study of kinesiology is the study of human motion. Something in motion whether it is a football or a snail has kinetic energy. The KMT makes several predictions about the behaviors of gases which w
