AN INTRODUCTION To Chemical Reactions

Types of Chemical Reactions

Parts of a Chemical Reaction Reactants = Chemical Ingredients of the Reaction Products = New Substances Formed During the Reaction

In all chemical reactions, there is a change in energy. Exothermic Chemical Reaction Endothermic Chemical Reaction

Chemical reactions are often classified into 5 categories.

Lab: “Black” Sugar?

Sugar = Sugar Charcoal & Steam Lab: Black Sugar? Sugar = Sugar Charcoal & Steam C12 H 24 O11 = C + H2O

Decomposition Reaction A single compound breaks down into two or more substances.

Rules for Product Determination All binary compounds will break down into their elements. Remember the “Lucky 7” N2 O2 F2 Cl2 Br2 I2

Rules for Product Determination All binary compounds will break down into their elements. All carbonates (CO3) break down to carbon dioxide (CO2) and an oxide!

Rules for Product Determination All binary compounds will break down into their elements. All carbonates (CO3) break down to carbon dioxide (CO2) and an oxide! All chlorates (ClO3) break down to oxygen (O2) and a binary salt.

Rules for Product Determination Acids containing oxygen will break down into water (H2O) and a metal oxide.

Rules for Product Determination Acids containing oxygen will break down into water (H2O) and a metal oxide. Bases will break down into water (H2O) and a nonmetal oxide.

Two or more substances combine forming a new substance. Synthesis Reaction Two or more substances combine forming a new substance.

Lab: Limewater Production

Building Muscle

Rules for Product Determination Direct union of two elements will produce a binary compound.

Rules for Product Determination Direct union of two elements will produce a binary compound. Metallic oxides and carbon dioxide (CO2) react to form carbonates (CO3)!

Rules for Product Determination Direct union of two elements will produce a binary compound. Metallic oxides and carbon dioxide (CO2) react to form carbonates (CO3). Binary salts and oxygen react to produce a chlorate (ClO3).

Rules for Product Determination A nonmetallic oxide plus water (H2O) will produce an acid.

Rules for Product Determination A nonmetallic oxide plus water (H2O) will produce an acid. A metallic oxide plus water (H2O) will produce a base.

Rules for Product Determination Direct union of two elements will produce a binary compound. Metallic oxides and carbon dioxide (CO2) react to form carbonates (CO3). Binary salts and oxygen react to produce a chlorate (ClO3).

Lab: Single Replacement Reaction

Lab: Metals in Aqueous Solution Interactive

Rules for Product Determination Determine if the reactant element is normally positive or negative. O2 = negative 2

Rules for Product Determination Determine if the reactant element is normally positive or negative. Identify the opposite charged portion of the compound and it’s valence number. Zn = +2

Rules for Product Determination Determine if the reactant element is normally positive or negative. Identify the opposite charged portion of the compound and it’s valence number. Write the correct formula of the new compound. ZnS + O2 = ZnO

Rules for Product Determination Determine if the reactant element is normally positive or negative. Identify the opposite charged portion of the compound and it’s valence number. Write the correct formula of the new compound. Write the left over element as the second product, ZnS + O2 = ZnO + S

Double Replacement Reactions A reaction in which the elements in two compounds are exchanged.

Double Replacement Reactions

Precipitate Reactions (↓)

Lab: Double Exchange

Lab: Double Replacement

Combustion

Combustion Reaction

Lab: Combustion Reaction

Writing Chemical Equations

Writing Chemical Equations Step 1: Identify the type of chemical reaction.

Mr. G.’s Reaction Checklist

Mr. G.’s Reaction Checklist Follow this series of questions to identify which a type of chemical reaction. When you answer “yes” to a question… Follow this series of questions. When you can answer "yes" to a question, then stop! 1)  Does your reaction have oxygen as one of it's reactants and carbon dioxide and water as products? If yes, then it's a combustion reaction 2)  Does your reaction have two (or more) chemicals combining to form one chemical? If yes, then it's a synthesis reaction 3)  Does your reaction have one large molecule falling apart to make several small ones? If yes, then it's a decomposition reaction 4)  Does your reaction have any molecules that contain only one element? If yes, then it's a single displacement reaction 5)  Does your reaction have water as one of the products? If yes, then it's an acid-base reaction 6)  If you haven't answered "yes" to any of the questions above, then you've got a double displacement reaction

Mr. G.’s Reaction Checklist Does your reaction have oxygen (O2) one of it’s reactants and carbon dioxide (CO2)and water (H2O) as products? If the answer is “yes”, it is a COMBUSTION reaction!

Mr. G.’s Reaction Checklist Does your reaction have 2 or more reactants and only 1 product? If the answer is “yes”, it is a SYNTHESIS reaction!

Mr. G.’s Reaction Checklist Does your reaction have only 1 reactant but 2 or more products? If the answer is “yes”, it is a DECOMPOSITION reaction!

Mr. G.’s Reaction Checklist Does your reaction have a single element as a reactant and as a product? If the answer is “yes”, it is a SINGLE REPLACEMENT reaction! 6)  If you haven't answered "yes" to any of the questions above, then you've got a double displacement reaction

Mr. G.’s Reaction Checklist If you haven’t answered yes to any of the questions it is a DOUBLE REPLACEMENT reaction!

Writing Chemical Equations Step 1: Identify the type of chemical reaction. Step 2: Predict the product(s) formed in the reaction.

Lab: Predicting Products Interactive

Writing Chemical Equations Step 1: Identify the type of chemical reaction. Step 2: Predict the product(s) formed in the reaction. Step 3: