Chemistry: Unit 2 Review Lesson 16

Notes A paper copy of the review will be available on line if you would like me to post one. Please look through all of your notes. We have had 15 lessons. Each one has been labelled with the code U2-L#. If you are missing any please ask me for a copy so that I have time to get them to you.

How to study and get a very good mark Read through all of your notes Read through the review and highlight areas that you are unsure about, including key terms. Write out all of the key terms Answer all of the questions given and study old quizzes.

Chemical Changes Lessons (1-11)

Key Concepts •Properties Chemical change • Ions and molecules • Ionic and molecular compounds • Law of conservation of mass • Balanced chemical equations

Summary • During a chemical reaction, new substances are formed that have different properties from the reactants. • Metallic atoms form positive ions; non-metallic atoms form negative ions. • Polyatomic ions are charged groups of atoms. • Ionic compounds form between metals and non-metals.

Summary • Molecular compounds form between non-metals and non-metals. • The reactant(s) in a chemical reaction undergo chemical change(s). The product(s) of a chemical reaction have different properties than the reactant(s). • The law of conservation of mass states that mass will remain constant during any chemical reaction. • A word equation describes a chemical reaction using words.

Key Terms Read each one and then try to define it, if you do not know the meaning of it look it up in your notes and write it down.

Chemical Reactions Lessons (12-13)

Key Concepts • General chemical equations • Types of chemical equations: • Synthesis • Decomposition • Combustion • Single displacement • Double displacement

Summary • A general chemical equation (GCE) is an equation that uses letters of the alphabet (A, B, C, D, X), as well as some element symbols, to represent different chemical reactions. • In a synthesis reaction, two or more elements combine to produce at least one new substance. • In a decomposition reaction, a single compound is broken down into its elements.

Summary • A combustion reaction always involves oxygen as a reactant and carbon dioxide and water are often products. • In a single displacement reaction, a reactive metallic element can replace a less reactive metallic element in a compound. • In a double displacement reaction between two ionic compounds, the positive or negative ions switch places.

Key Terms Read each one and then try to define it, if you do not know the meaning of it look it up in your notes and write it down.

Acids and Bases Lessons (14-15)

Key Concepts • Properties of acids and bases • pH scale • Measuring pH • Neutralization

Summary • The pH of liquids can be determined using pH indicators. • An acid has a pH less than 7, a base has a pH greater than 7, and a neutral liquid has a pH equal to 7. • Neutralization is a chemical reaction between an acid and a base that produces water and a salt. • Neutralization reactions can be used to help solve chemical contamination problems in the environment.

Key Terms Read each one and then try to define it, if you do not know the meaning of it look it up in your notes and write it down.

Questions Please do as many of the questions as possible.