Drill: What is the big number used to balance equations?

Objective: The student will be able to: Complete Types of Chemical Reactions lab in order to identify and classify chemical reactions based on five general categories.

SAT/HSA Enrichment: Equations must be balanced in order to obey… a. Dalton’s Atomic Theory b. Law of Conservation of Energy c. Law of Conservation of Mass d. Law of Definite Composition e. Law of Multiple Proportions

Engagement: Quiz: Word equations and Balancing Chemical Equations (5 min)

Types of Chemical Reactions How many are there?

Types of Chemical Reactions The heat and smoke of burning charcoal are the products of a combustion reaction. Combustion is one of the five general types of chemical reactions. If you can recognize a reaction as being a particular type, you may be able to predict the products of the reaction.

Classifying Reactions The five general types of reaction are combination, decomposition, single-replacement, double-replacement, and combustion.

Classifying Reactions Combination Reactions A combination reaction is a chemical change in which two or more substances react to form a single new substance. When ignited, magnesium ribbon reacts with oxygen in the surrounding air to form magnesium oxide, a white solid. This is a combination reaction. Observing Why do you think this reaction was once used in flashbulbs for photography?

Classifying Reactions Decomposition Reactions A decomposition reaction is a chemical change in which a single compound breaks down into two or more simpler products. When orange-colored mercury(II) oxide is heated, it decomposes into its constituent elements: liquid mercury and gaseous oxygen. Comparing and Contrasting How are the two reactions pictured so far similar? How are they different?

Classifying Reactions Single-Replacement Reactions A single-replacement reaction is a chemical change in which one element replaces a second element in a compound. The alkali metal potassium displaces hydrogen from water and forms a solution of potassium hydroxide in a single-replacement reaction. The heat of the reaction is often sufficient to ignite the hydrogen. Inferring Why are alkali metals stored under mineral oil or kerosene?

Classifying Reactions The activity series of metals lists metals in order of decreasing reactivity.

Classifying Reactions Double-Replacement Reactions A double-replacement reaction is a chemical change involving an exchange of positive ions between two compounds. Aqueous solutions of potassium carbonate and barium chloride react in a double-replacement reaction to form the white precipitate barium carbonate. Potassium chloride, the other product of the reaction, remains in solution.

Classifying Reactions Combustion Reactions A combustion reaction is a chemical change in which an element or a compound reacts with oxygen, often producing energy in the form of heat and light. Methane gas reacts with oxygen from the surrounding air in a combustion reaction to produce carbon dioxide and water. Inferring What else is produced in this reaction?

Predicting the Products of a Chemical Reaction The number of elements and/or compounds reacting is a good indicator of possible reaction type and thus possible products.

Predicting the Products of a Chemical Reaction The five types of chemical reactions discussed in this chapter are summarized here.

Predicting the Products of a Chemical Reaction The five types of chemical reactions discussed in this chapter are summarized here.

Predicting the Products of a Chemical Reaction The five types of chemical reactions discussed in this chapter are summarized here.

Predicting the Products of a Chemical Reaction

Predicting the Products of a Chemical Reaction The five types of chemical reactions discussed in this chapter are summarized here.

Section Quiz 1. What type of reaction is described by the following equation? 6Li + N2  2Li3N combination reaction decomposition reaction single-replacement reaction combustion reaction

Section Quiz 2. Balance the following equation and indicate whether it represents a combustion, combination, or decomposition reaction. H2SO4  H2O2 + SO2 H2SO4  H2O2 + SO2, combination reaction H2SO4  H2O2 + SO2, decomposition reaction H2SO4  2H2O2 + SO2, combination reaction H2SO4  2H2O2 + SO2, decomposition reaction

Section Quiz 3. Predict the missing product in the following unbalanced equation. Pb(NO3)2 + KOH  KNO3 + ____________ PbOH2 Pb(OH)4 Pb(OH)2 PbOH

Lab 50 min Types of Reactions Purpose: To identify and classify chemical reactions based on five general categories. 50 min

Homework Assignment: Classification of Chemical Reactions

Summary Questions: Did we accomplish the objective? Explain. How many different types of reactions are there? What are the different types of reactions? What type of compounds are usually reactants in combustion reactions? What two compounds are the products of combustion reactions? What is a combination reaction?