FinalExamStudyGuide_Part1

FinalExamStudyGuide_Part1 - Study Guide for Final Exam...

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Study Guide for Final Exam Chapters 21 and 23 I. Elements of Chemistry You need to know: 1) Physical properties are the properties that describe the look or feel of a substance, such as color, hardness, texture, and phase. 2) Chemical properties are the properties that describe how one substance reacts with others or how a substance transforms. 3) Any change in a substance that involves a rearrangement of the way its atoms are bonded is called a chemical reaction . During a chemical reaction atoms rearrange to create one or more new compounds. 4) Reacting substances are called reactants. The products of chemical reaction are newly formed substances. 5) The Law of Mass Conservation : Matter is neither created nor destroyed during chemical reactions. 6) A compound is represented by its chemical formula . A chemical compound is a substance consisting of two or more elements chemically bonded together in a fixed proportion by mass. An index in chemical formula shows the number of same element in a chemical compound. 7) A chemical equation is balanced if number of times each element appears as a reactant is equal to the number of times it appears as a product. 8) You can balance unbalanced equation by adding or changing coefficients to produce correct ratios following the following rules: Step 1. Balance one element at a time. Modify the coefficients to make this element appear the same number of times on both sides of arrow. Start with the reactant having the most complex formula and finish with the reactant having the simplest formula. Step 2 . If you incidentally unbalance an element that you worked with previously, leave it alone and come back to it only after you have worked with all other elements. Step 3. After you have worked with each element, make another pass through the equation, changing coefficients as needed Step 4 . Repeat Step 3 until all elements are balanced. Step 5. If necessary, minimize the coefficients by dividing by the lowest common denominator. YOU SHOULD BE ABLE TO BALANCE CHEMICAL REACTIONS ! Practice! 9 ) A chemical bond is the attraction between two atoms that holds them together in molecule. 1
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10) There are two types of chemical bonds: Ionic bonds result from a transfer of valence electrons. Ionic bonds do not share electrons. Covalent bon ds result from a sharing of valence electrons. The outer shells of two atoms that are covalently bonded are overlapped. 11 ) Definition of a molecule : A molecule is any group of atoms held together by covalent bonds. 12) Molecular Polarity results from an uneven distribution of electrons. For example, a water molecule H 2 O is a polar molecule Chapter 33 II. Earth 1. 1. Earth Architecture Earth Architecture The study of seismic waves (Chapter 32) reveals the Earth's architecture. The study of seismic waves (Chapter 32) reveals the Earth's architecture. From the Earth’s center to the Earth’s surface:
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FinalExamStudyGuide_Part1 - Study Guide for Final Exam...

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