How do you observe when you just look at the picture
How can you describe what you see so that others can understand results of careful observation?
These are the questions you will explore in taking a closer look at matter!
Science applies the same skills you use to interpret the picture to make increasingly presice observationand detailed interences. Detailed observation takes so much time and effort that it is necessary to speciallize.
Chemists specialize in matter; what it is, how one kind differs from another, what differencekinds have in common, how one kind can be changed to another, and even how mateer can be kept the same.
2-1 What You Know about Matter
By living in a world of matter, you have learned a tremendous amout about the subject. (ex. water normally exists as a liquid) A variety changes can be understood using a few powrful ideas may be even more amazing to you now. To see how a few ideas can explain a lots of observation, you will learn to specialize, you will look carefully at a few familiar substances , classify them, and make generalizations about them based on the reqularities you see.
Property
- characteristic of matter
- describe matter specifically and can be used to identify matter
- ex. colour, tast, boiling point
- part of the study of science is the accumulation of such information
- another part is using the information you have to make sense of the world by decribing it with increasingly greater precision
Mixture - Matter that is easily separated into component parts. It is impure.
Classifying matter into pure forms and mixtures is one step toward understanding matter and developing a language to describe that understanding. It is based on experience. Chemists derive the idea of mixture and pure substance to describe matter.
People purify water by adding alum and lime to the water, and a gelatinous material is produced. As this gelatinous material settles out or is removed by filtering through beds of sand, small particles suspended in the water stick to the gelatinous material and are removed.
Scattering cannot be used as a test of whether a material is pure. Mixtures like salt water or sugar water that look unifrom throughout and do scatter light are called solutions.
Salt water cna sugar water can be separated into their component parts using a procedure called destillation.
Although most mistures containing water can be separated by distillation, some cannot.
ex. household ammonia, whisky
Many mistures are difficult to separate . Such mixtures may be considered pure for many years until someone invents a new procedure or a better instrument for analyzing and separation. Many environmental conerns have come about because new and better techniques have been found to detect thier impurities.
Video: Classifying Matter and Pure Substances
Video: Solution and Classifying Matter
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