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Chapter 2, Section 1 pages 58-67. Describing Matter. What’s Chemistry?. Chemistry is the study of properties of matter and how matter changes. What is Matter?. Anything that has mass and takes up space. All the stuff around you is matter.
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Chapter 2, Section 1pages 58-67. Describing Matter
What’s Chemistry? Chemistry is the study of properties of matter and how matter changes.
What is Matter? • Anything that has mass and takes up space. • All the stuff around you is matter. • Air, plastic, wood, glass, paper and cloth are all examples of matter. • Every form of matter has two kinds of properties-Physical and Chemical.
Properties of Matter • Matter can have many different properties, or characteristics. • Materials can be hard or soft, rough or smooth, hot or cold, liquid, solid or gas.
What is a Substance? • A single kind of matter that is pure, meaning it always has a specific kind of make-up. • Elements are the simplest substances. • Table salt and Sugar are examples of pure substances. • Figure 1, page 59.
Physical Properties of Matter • A physical property is a characteristic of a pure substance that can be observed without changing it into another substance. • Two physical properties of metals are luster (how shiny they are) and the ability to conduct (carry) heat and electricity. • Figure 2, page 60.
Chemical Properties of Matter • A chemical property is a characteristic of a pure substance that describes it’s ability to change into different substances. • A chemical property of methane is it can catch fire and burn in air. • Figure 3, page 61
What is an Element? • An element is a pure substance that cannot be broken down into any other substance by chemical or physical means. • Elements are the simplest substances. • Each element can be identified by it’s specific physical and chemical properties. • Figure 4, page 62.
What is an Atom? • The basic particle from which all elements are made. • Figure 5, page 63.
Chemical Bond • Chemical Bonds are formed when atoms combine. • This is caused by a force of attraction between two atoms. • Chemical bonds form Molecules. • Molecules are two or more atoms held together by chemical bonds. • Figure 6, page 63.
Compounds!!! • A pure substance made of two or more elements chemically combined in a set ratio. • Salt is a compound! • Figure 7, page 64. • When elements chemically combine, they form compounds having properties that are different from those of the uncombined elements.
Compound (Continue) • A compound may be represented by a chemical formula. • A chemical formula shows the elements in a compound and the ratio of the atoms. • Example-> Calcium Carbonate is a compound. It is written as CaCO3.
Mixtures • A mixture is made up of two or more substances, but are not chemically combined. • Heterogeneous mixture: You can see the different parts. • Homogeneous mixture: So evenly mixed you can’t see the different parts.
Solution • A solution is an example of a homogeneous mixture. • Air is a solution of Nitrogen gas (N2) and Oxygen gas (O2). • Brass is a solution of Copper and Zinc. • Figures 8 and 9, page 65.
Separating Mixtures • A compound is difficult to separate into it’s elements. • A mixture is easy to separate into it’s components because each component keeps it’s own properties. • Figure 10, pages 66-67.
