AT_Classification of Matter Lesson

Classification of Matter 

Chemistry is the study of matter. So, let's begin by classifying matter into two major categories, pure substances and mixtures. Elements and compounds make up a category of matter known as pure substances. These pure substances have a constant composition. Although there are millions of pure substances, finding them in nature is rare. Most of the time, compounds and elements are found as a part of a mixture. Mixtures do not have constant composition, their composition varies. The composition can appear consistent, as is the case with homogeneous mixtures. Heterogeneous mixtures occur when the mixture does not appear consistent. A mixture that is homogeneous is also called a solution.

Study the charge below and answer the questions underneath.  

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Properties of Matter

Properties of substances are very important in chemistry and can be classified several ways. All properties are either intensive or extensive. An intensive property does not depend on the amount of sample that you assessing. An example of an intensive property is boiling point. It does not matter if you have 1 liter or 1 swimming pool of water, the boiling point will be 100°C. Boiling point is an intensive property. A property that does depend on the amount of sample is called an extensive property. The mass of water is an extensive property. The mass of 1 liter of water would be vastly different from the mass of a swimming pool of water.

Chemical and Physical Properties and Changes

Another way that properties are classified depends on how much the substance changes when measuring the property. Physical properties are measured while the chemical composition of the sample remains intact. Examples of physical properties are color, texture, and whether or not something will dissolve. Chemical properties >are those where the chemical composition of the substance will be permanently altered when the property is measured. Flammability, reactivity, and radioactivity are all examples of chemical properties.

So, the next question on your mind should be, what are elements made of? The answer is atoms. But, what is an atom? This might sound like a simple question, but it is quite complex. To better understand the atom, let's look at it from a historical perspective. 

Remember to work on the module practice problems as you complete each section of content.

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