8 Chemical Equations Flames and sparks result when aluminum foil is dropped into liquid bromine. Foundations of College Chemistry, 14th Ed. Morris Hein and Susan Arena Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

© 2014 John Wiley & Sons, Inc. All rights reserved. Chapter Outline 8.1 The Chemical Equation 8.2 Writing and Balancing Chemical Equations 8.3 Types of Chemical Equations 8.4 Heat in Chemical Reactions 8.5 Global Warming: The Greenhouse Effects © 2014 John Wiley & Sons, Inc. All rights reserved.

Chemical Equations Chemical Equations: shorthand notation for chemical changes or reactions. Chemists use chemical equations to: Summarize a chemical reaction by displaying the substances reacting and forming. Indicate specific amounts of materials consumed or produced during the reaction. Reactants: substances consumed during the reaction. Products: substances formed during the reaction. a A + b B c C + d D Atom balance must be maintained in all chemical reactions. All atoms from reactants must appear as part of products. © 2014 John Wiley & Sons, Inc. All rights reserved.

General Structure of Chemical Equations: 1. Reactants and products are separated by an arrow. Reactants are on the left side of the arrow, products are on the right. a A + b B c C + d D Reactants Products 2. Whole number coefficients are placed in front of substances to balance the atoms in the equation. The numbers indicate the units of the substance reacted or formed during the reaction. The coefficient 1 is not written in a balanced equation. © 2014 John Wiley & Sons, Inc. All rights reserved.

Chemical Equations General Structure of Chemical Equations: 3. Information about the reaction (temperature, time) may be placed above or below the reaction arrow. a A + b B c C + d D Δ Δ indicates heat 4. The physical state is written in brackets after the formula of the substance. (g) for gas, (l) for liquid, (s) for solid, (aq) for aqueous a A (s) + b B (l) c C (g) + d D (s) © 2014 John Wiley & Sons, Inc. All rights reserved.

© 2014 John Wiley & Sons, Inc. All rights reserved. Chemical Equations Symbol Summary Symbol Significance Produces (points towards products) (s) Solid (written after substance) (l) Liquid (written after substance) (g) Gas (written after substance) (aq) Substance dissolved in an aqueous solution Heat is added (above or below reaction arrow) Δ © 2014 John Wiley & Sons, Inc. All rights reserved.

Law of Conservation of Mass the total mass of substances in a chemical reaction must remain constant. water hydrogen + oxygen 100.0 g 11.2 g 88.8 g reactants 100.0 g total of products In any chemical reaction: Mass of reactants = Mass of products © 2014 John Wiley & Sons, Inc. All rights reserved.

Writing and Balancing Chemical Equations Balanced chemical equations: contain the same number of each kind of atom on both sides of the equation. General Method for Writing and Balancing Chemical Equations 1. Identify the Reaction. Write a word equation for the reaction. mercury(II) oxide mercury + oxygen Δ 2. Write the unbalanced (skeleton) equation. Write the correct formula for each substance HgO Hg + O2 Δ © 2014 John Wiley & Sons, Inc. All rights reserved.

Writing and Balancing Chemical Equations General Method for Writing and Balancing Chemical Equations 3. Balance the equation. a. Count the number of each atom on the reactants and products side and determine what requires balancing. HgO Hg + O2 Δ Hg: 1 O: 1 Hg: 1 O: 2 Oxygen atoms need balancing on the reactants side. © 2014 John Wiley & Sons, Inc. All rights reserved.

Writing and Balancing Chemical Equations General Method for Writing and Balancing Chemical Equations b. Balance each element sequentially, using whole numbers. It is often best to balance metals first. 2 HgO Hg + O2 Δ Hg: 2 O: 2 Hg: 1 O: 2 Now Hg atoms need balancing on the products side. c. Check after adding coefficients that all atoms still balance. Adjust as needed (a 2 is needed in front of Hg). © 2014 John Wiley & Sons, Inc. All rights reserved.

Writing and Balancing Chemical Equations General Method for Writing and Balancing Chemical Equations d. Do a final check to make sure all atoms now balance on both sides of the equation. 2 HgO 2 Hg + O2 Δ Hg: 2 O: 2 Hg: 2 O: 2 Note: always use the smallest whole numbers! 4 HgO 4 Hg + 2 O2 Δ Balanced but incorrect form! © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for when magnesium metal undergoes combustion to produce magnesium oxide. 1. Identify the Reaction. Write a word equation for the reaction. magnesium + oxygen magnesium oxide 2. Write the unbalanced (skeleton) equation. Write the correct formula for each substance Mg + O2 MgO © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for when magnesium metal undergoes combustion to produce magnesium oxide. 3. Balance the equation. a. Count the number of each atom on the reactants and products side and determine what requires balancing. Mg + O2 MgO Mg: 1 O: 2 Mg: 1 O: 1 Oxygen needs balancing on the products side. © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for when magnesium metal undergoes combustion to produce magnesium oxide. b. Balance each element sequentially, using whole numbers. It is often best to balance metals first. Mg + O2 2 MgO Mg: 1 O: 2 Mg: 2 O: 2 Mg now needs balancing on the reactants side. © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for when magnesium metal undergoes combustion to produce magnesium oxide. c. Check after adding coefficients that all atoms still balance. Adjust as needed (a 2 is needed in front of Mg). 2 Mg + O2 2 MgO Mg: 2 O: 2 Mg: 2 O: 2 d. Do a final check to make sure all atoms now balance on both sides of the equation. © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the decomposition of potassium chlorate upon heating to give oxygen and potassium chloride. 1. Identify the Reaction. Write a word equation for the reaction. Potassium chlorate potassium chloride + oxygen 2. Write the unbalanced (skeleton) equation. Write the correct formula for each substance KClO3 KCl + O2 Δ © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the decomposition of potassium chlorate upon heating to give oxygen and potassium chloride. 3. Balance the equation. a. Count the number of each atom on the reactants and products side and determine what requires balancing. KClO3 KCl + O2 Δ K: 1 Cl: 1 O: 3 K: 1 Cl: 1 O: 2 Oxygen needs balancing on both sides of the equation. © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the decomposition of potassium chlorate upon heating to give oxygen and potassium chloride. b. Balance each element sequentially, using whole numbers. It is often best to balance metals first. 2 KClO3 KCl + 3 O2 Δ K: 2 Cl: 2 O: 6 K: 1 Cl: 1 O: 6 The lowest common multiple of 2 and 3 is 6. Add coefficients as appropriate to make 6 O atoms. © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the decomposition of potassium chlorate upon heating to give oxygen and potassium chloride. c. Check after adding coefficients that all atoms still balance. Adjust as needed (a 2 is needed in front of KCl). 2 KClO3 2 KCl + 3 O2 Δ K: 2 Cl: 2 O: 6 K: 2 Cl: 2 O: 6 d. Do a final check to make sure all atoms now balance on both sides of the equation. © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the reaction of silver nitrate with hydrogen sulfide to produce silver sulfide and nitric acid. 1. Identify the Reaction. Write a word equation for the reaction. silver nitrate + hydrogen sulfide silver sulfide + nitric acid 2. Write the unbalanced (skeleton) equation. Write the correct formula for each substance AgNO3 + H2S Ag2S + HNO3 © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the reaction of silver nitrate with hydrogen sulfide to produce silver sulfide and nitric acid. 3. Balance the equation. a. Count the number of each atom on the reactants and products side and determine what requires balancing. AgNO3 + H2S Ag2S + HNO3 Ag: 1 H: 2 S: 1 NO3: 1 Ag: 2 H: 1 S: 1 NO3: 1 Note: If polyatomic ions do not change, they can be balanced as a “unit”. © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the reaction of silver nitrate with hydrogen sulfide to produce silver sulfide and nitric acid. b. Balance each element sequentially, using whole numbers. It is often best to balance metals first. 2 AgNO3 + H2S Ag2S + HNO3 Ag: 2 H: 2 S: 1 NO3: 2 Ag: 2 H: 1 S: 1 NO3: 1 H and NO3 are now unbalanced. © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice c. Check after adding coefficients that all atoms still balance. Adjust as needed (a 2 is needed in front of HNO3). 2 AgNO3 + H2S Ag2S + 2 HNO3 Ag: 2 H: 2 S: 1 NO3: 2 Ag: 2 H: 2 S: 1 NO3: 2 H and NO3 are now balanced. d. Do a final check to make sure all atoms now balance on both sides of the equation. © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the combustion of butane (C4H10) gas, where carbon dioxide and water are the only products. a. C4H10 + 5 O2 4 CO2 + 5 H2O b. C4H10 + O2 CO2 + H2O c. 2 C4H10 + 13 O2 8 CO2 + 10 H2O d. C4H10 + 6.5 O2 4 CO2 + 5 H2O 1. Identify the Reaction. butane + oxygen carbon dioxide + water 2. Write the unbalanced (skeleton) equation. C4H10 + O2 CO2 + H2O © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the combustion of butane (C4H10) gas, where carbon dioxide and water are the only products. 3. Balance the equation. C4H10 + 6.5 O2 4 CO2 + 5 H2O C: 4 H: 10 O: 13 C: 4 H: 10 O: 13 Atoms balance, but all coefficients must be whole numbers. Multiply equation by 2. 2 C4H10 + 13 O2 8 CO2 + 10 H2O © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the reaction of magnesium hydroxide and phosphoric acid to form magnesium phosphate and water. a. 3 Mg(OH)2 + 2 H3PO4 Mg3(PO4)2 + H2O b. Mg(OH)2 + H3PO4 Mg3(PO4)2 + H2O c. 3 Mg(OH)2 + H3PO4 Mg3(PO4)2 + H2O d. 3 Mg(OH)2 + 2 H3PO4 Mg3(PO4)2 + 6 H2O 1. Identify the Reaction. magnesium hydroxide + phosphoric acid magnesium phosphate + water 2. Write the unbalanced (skeleton) equation. Mg(OH)2 + H3PO4 Mg3(PO4)2 + H2O © 2014 John Wiley & Sons, Inc. All rights reserved.

Balancing Chemical Equations Practice Write the balanced chemical equation for the reaction of magnesium hydroxide and phosphoric acid to form magnesium phosphate and water. 3. Balance the equation. 3 Mg(OH)2 + 2 H3PO4 Mg3(PO4)2 + H2O Mg: 3 H: 12 O: 6 PO4: 2 Mg: 3 H: 2 O: 1 PO4: 2 To balance water, add a coefficient of six. 3 Mg(OH)2 + 2 H3PO4 Mg3(PO4)2 + 6 H2O © 2014 John Wiley & Sons, Inc. All rights reserved.

Information in a Chemical Equation © 2014 John Wiley & Sons, Inc. All rights reserved.

Information from a Chemical Equation From the chemical equation below, how many moles of HF can be produced from 2 moles of hydrogen gas? H2 (g) + F2 (g) 2 HF (g) For every 1 mol of H2, 2 mol of HF can be produced. Two moles of H2 could then produce 4 moles of HF. © 2014 John Wiley & Sons, Inc. All rights reserved.

Information from a Chemical Equation From the chemical equation below, how many moles of oxygen are needed to burn 2 molecules of propane (C3H8)? C3H8 + 5 O2 3 CO2 + 4 H2O a. 5 molecules of oxygen b. 6 molecules of oxygen c. 10 molecules of oxygen d. 15 molecules of oxygen For every 1 molecule of propane, 5 molecules of O2 are needed to fully react. Two molecules of propane would then require 2 x 5 = 10 molecules of oxygen. © 2014 John Wiley & Sons, Inc. All rights reserved.

Types of Chemical Equations Reactions are classified into subtypes to aide in predicting the products of chemical reactions. Reactions are classified into five major categories: 1. Combination reactions 2. Decomposition reactions 3. Single displacement reactions 4. Double displacement reactions 5. Oxidation-reduction (redox) reactions (Chapter 17) © 2014 John Wiley & Sons, Inc. All rights reserved.

Combination Reactions Two reactants combine to give a single product. A + B AB where A or B are elements/compounds and AB is a compound. Representative Examples metal + nonmetal salt 2 Na (s) + Cl2 (g) 2 NaCl (s) metal oxide + water metal hydroxide CaO (s) + H2O (l) Ca(OH)2 (aq) Violent reaction occurs when Al and Br2 react to form AlBr3. 2 Al (s) + 3 Br2 (l) 2 AlBr3 (s) © 2014 John Wiley & Sons, Inc. All rights reserved.

Decomposition Reactions A single reactant breaks down (decomposes) into two or more products . AB A + B Representative Examples 2 PbO2 (s) 2 PbO(s) + O2 (g) Δ Metal oxides often decompose when heated. Carbonates form CO2 when heated. CaCO3 (s) CaO (s) + CO2 (g) H2O2 decomposes to steam (H2O (g)) and O2. 2 H2O2 (l) 2 H2O (g) + O2 (g) © 2014 John Wiley & Sons, Inc. All rights reserved.

Single Displacement Reactions One element (A) reacts with a compound (BC) to replace one element in the compound, giving a new element (B) and a different compound (AC). A + BC B + AC where A and B are metals and A is more reactive. or A + BC C + AB where A and C are halogens and A is more reactive. Example Zn reacts with HCl, resulting in H2 gas evolution. Zn (s) + 2 HCl (aq) ZnCl2 (aq) + H2 (g) © 2014 John Wiley & Sons, Inc. All rights reserved.

Activity Series Table listing in order of decreasing reactivity of various elements. More reactive elements replace less reactive ones. 2 Al (s) + 3 CuCl2 (s) 2 AlCl3 (aq) + 3 Cu (s) 2 Ag (s) + 3 CuSO4 (s) No Reaction © 2014 John Wiley & Sons, Inc. All rights reserved.

General Types of Single Displacement Reactions Where A and B are metals and A is more reactive: Metal + acid hydrogen + salt 2 Al (s) + 3 H2SO4 (aq) Al2(SO4)3 (aq) + 3 H2 (g) Metal + water hydrogen + metal hydroxide/oxide 2 Na (s) + 2 H2O (l) 2 NaOH (aq) + H2 (g) Metal (or halogen) + salt metal (or halogen) + salt Fe (s) + CuSO4 (aq) Cu (s) + FeSO4 (aq) Cl2 (g) + 2 KI (aq) I2 (s) + 2 KCl (aq) © 2014 John Wiley & Sons, Inc. All rights reserved.

Single Displacement Reactions Will a reaction occur between Ni and HCl? If so, write the balanced chemical equation. Based on the reactivity series, Ni is more reactive than hydrogen, so a reaction occurs. Ni (s) + HCl (aq) H2 (g) + NiCl2 (aq) Will a reaction occur between Sn and AlCl3? If so, write the balanced chemical equation. Based on the reactivity series, Sn is less reactive than Al, so no reaction occurs. Sn (s) + AlCl3 (aq) No Reaction © 2014 John Wiley & Sons, Inc. All rights reserved.

Single Displacement Reactions Write the reaction (if it occurs) between the following substances: Iron metal and a solution of magnesium chloride a. Fe (s) + MgCl2 (aq) No Reaction b. Fe (s) + MgCl2 (aq) FeCl2 (aq) + Mg (s) Iron is less reactive than Mg, so no reaction occurs. © 2014 John Wiley & Sons, Inc. All rights reserved.

Double Displacement Reactions Two compounds exchange partners with one another to yield two new compounds. AB + CD AD + CB Physical evidence for a double displacement reaction include: heat evolution, formation of a precipitate or gas production. PbI2 precipitates from the reaction of Pb(NO3)2 with KI. Pb(NO3)2 (aq) + 2 KI (aq) PbI2 (s) + 2KNO3 (aq) © 2014 John Wiley & Sons, Inc. All rights reserved.

General Types of Double Displacement Reactions Acid/Base Neutralization acid + base salt + water + heat HCl (aq) + NaOH (aq) NaCl (aq) + H2O (l) + heat Metal Oxide (base) + Acid Metal oxide + acid salt + water + heat CuO (s) + 2 HNO3 (aq) Cu(NO3)2 (aq) + H2O (l) + heat © 2014 John Wiley & Sons, Inc. All rights reserved.

General Types of Double Displacement Reactions Formation of a Precipitate Product solubilities are based on the table in Appendix V Insoluble products are indicated by (s) BaCl2 (aq) + 2 AgNO3 (aq) 2 AgCl (s) + 2 KNO3 (aq) Gas Formation H2SO4 (l) + NaCl (s) NaHSO4 (aq) + HCl (g) A gas can also form from a secondary reaction after displacement 2 HCl (aq) + Na2CO3 (aq) 2 NaCl (aq) + H2CO3 (aq) H2CO3 (aq) H2O (l) + CO2 (g) © 2014 John Wiley & Sons, Inc. All rights reserved.

Writing Reaction Equations Practice Write the reaction equation between aqueous solution of hydroiodic acid and sodium hydroxide. First convert names to chemical formulas and determine the type of reaction. HI (acid)/NaOH(base) Neutralization Reaction acid + base salt + water HI (aq) + NaOH (aq) NaI (aq) + H2O (l) Salt formula must charge balance (Na+ and I–) © 2014 John Wiley & Sons, Inc. All rights reserved.

Writing Reaction Equations Practice Write the balanced reaction equation between aqueous barium chloride and magnesium sulfate. First convert names to chemical formulas and determine the type of reaction. BaCl2/MgSO4 Both compounds are ionic, but not acids or bases. The reaction is likely a double displacement. BaCl2 (aq) + MgSO4 (aq) BaSO4 (s) + MgCl2 (aq) Based on Appendix V, BaSO4 will precipitate, providing a driving force for the reaction. © 2014 John Wiley & Sons, Inc. All rights reserved.

Writing Reaction Equations Practice Write the balanced reaction equation between aqueous potassium phosphate and barium chloride. 1. Convert names to formulas K3PO4/BaCl2 Both compounds are ionic, but not acids or bases. The reaction is likely a double displacement. Based on Appendix V, Ba3(PO4)2 will precipitate, providing a driving force for the reaction a. K3PO4 (aq) + BaCl2 (aq) No Reaction b. K3PO4 (aq) + BaCl2 (aq) KCl (aq) + Ba3(PO4)2 (aq) c. 2 K3PO4 (aq) + 3 BaCl2 (aq) 6 KCl (aq) + Ba3(PO4)2 (s) d. 2 K3PO4 (aq) + 3 BaCl2 (aq) 6 KCl (s) + Ba3(PO4)2 (aq) © 2014 John Wiley & Sons, Inc. All rights reserved.

Writing Reaction Equations Practice Write the balanced reaction equation between aqueous ammonium chloride and sodium nitrate. 1. Convert names to formulas NH4Cl/NaNO3 Both compounds are ionic. The reaction is likely a double displacement. Based on Appendix V, neither compound will precipitate. a. NH4Cl (aq) + NaNO3 (aq) No Reaction b. NH4Cl (aq) + NaNO3 (aq) NH4NO3 (aq) + NaCl (aq) c. NH4Cl (aq) + NaNO3 (aq) NH4NO3(s) + NaCl (aq) d. NH4Cl (aq) + NaNO3 (aq) NH4NO3 (aq) + NaCl (s) © 2014 John Wiley & Sons, Inc. All rights reserved.

Heat in Chemical Reactions Terminology Energy transfer and changes accompany any chemical reaction. Heat of reaction: quantity of heat actually produced during a chemical reaction. Units: kilojoules (kJ) or kilocalories (kcal) Exothermic reactions: release heat H2 (g) + Cl2 (g) 2 HCl (g) + 185 kJ Heat can be treated as a product Endothermic reactions: absorb heat N2 (g) + O2 (g) + 181 kJ 2 NO (g) Heat can be treated as a reactant © 2014 John Wiley & Sons, Inc. All rights reserved.

Heat in Chemical Reactions Terminology Energy transfer and changes accompany any chemical reaction. Heat of reaction: quantity of heat actually produced during a chemical reaction. Units: kilojoules (kJ) or kilocalories (kcal) C (s) + O2 (g) CO2 (g) + 393 kJ 1 mol of C reacts with 1 mol of O2 to provide 1 mol of CO2 and 393 kJ of heat are released. © 2014 John Wiley & Sons, Inc. All rights reserved.

Heat in Chemical Reactions Practice In the reaction: H2 (g) + I2 (s) + 12.6 kJ 2 HI (g) When 4 moles of HI are produced: a. 12.6 kJ of energy is absorbed b. 25.2 kJ of energy is absorbed c. 12.6 kJ of energy is released d. 25.2 kJ of energy is released 12.6 kJ are absorbed to form 2 mol of HI. 2 x 12.6 kJ are needed to produce 4 mol of HI. © 2014 John Wiley & Sons, Inc. All rights reserved.

Heat as an Energy Transfer Vehicle in Nature Photosynthesis: converts energy in the form of light from the sun into chemical energy (bonds in glucose). 6 CO2 (g) + 6 H2O (l) + 2519 kJ C6H12O6 + 6 O2 (g) glucose Photosynthesis is endothermic: the needed energy is supplied by sunlight. © 2014 John Wiley & Sons, Inc. All rights reserved.

Heat as an Energy Transfer Vehicle in Nature Fossil Fuels: petroleum, coal, and natural gas all release significant amounts of energy during combustion. CH4 (g) + 2 O2 (g) CO2 (g) + 2 H2O (g) + 890 kJ Combustion does not occur at normal temperatures without a spark. Activation energy: Amount of energy needed to initiate a chemical reaction. © 2014 John Wiley & Sons, Inc. All rights reserved.

Graphical Representations of Endothermic Reactions Reaction Coordinate Diagram Activation energy: Amount of energy needed to initiate a chemical reaction. Products are at a higher potential energy than reactants. © 2014 John Wiley & Sons, Inc. All rights reserved.

Graphical Representations of Exothermic Reactions Reaction Coordinate Diagram Products are at a lower potential energy than reactants. Activation energy: Amount of energy needed to initiate a chemical reaction. © 2014 John Wiley & Sons, Inc. All rights reserved.

Global Warming: The Greenhouse Effect Fossil fuels produce CO2 during combustion. 50 billion tons of CO2 are released into the atmosphere annually. Concentration of CO2 in the atmosphere. The average global temperature has risen by 0.74 ºC over the past century. © 2014 John Wiley & Sons, Inc. All rights reserved.

Global Warming: The Greenhouse Effect Other greenhouse gases also affect the atmosphere. Methane (CH4) is a very potent greenhouse gas. Levels of methane have increased over the past century due to coal mining, agricultural development and cows! © 2014 John Wiley & Sons, Inc. All rights reserved.

Global Warming: The Greenhouse Effect How do greenhouse gases warm the atmosphere? Greenhouse gases trap heat near Earth’s surface. Solar radiation warms the Earth’s surface. Greenhouse gases absorb some of this heat, which warms the atmosphere. Greenhouses operate in a similar fashion, allowing sunlight in but not the outflow of heat produced. © 2014 John Wiley & Sons, Inc. All rights reserved.

Learning Objectives 8.1 The Chemical Equation Describe the information present in a chemical equation. 8.2 Writing and Balancing Chemical Equations Write and balance chemical equations. 8.3 Types of Chemical Equations Give examples of the following types of reactions: combination, decomposition, single displacement and double displacement. © 2014 John Wiley & Sons, Inc. All rights reserved.

Learning Objectives 8.4 Heat in Chemical Reactions Explain the following terms as they relate to a chemical reaction: exothermic, endothermic, heat of a reaction and activation energy. 8.5 Global Warming: The Greenhouse Effect Recognize CO2 levels are increasing and the effect greenhouse gases have on warming the atmosphere near the Earth’s surface. © 2014 John Wiley & Sons, Inc. All rights reserved.