Chapter 5 Chemical Reactions and Quantities

Chapter 5Chemical Reactions and Quantities Mole Relationships in Chemical Equations LecturePLUS Timberlake 99

Mole-Mole Factors • Show the mole-to-mole ratio between two of the substances in a balanced equation • Use the coefficients of two substances in the equation LecturePLUS Timberlake 99

Writing Mole Factors 4 Fe + 3 O2 2 Fe2O3 Fe and O2 4 mole Feand 3 mole O2 3 mole O24 mole Fe Fe and Fe2O34 mole Fe and 2 mole Fe2O3 2 mole Fe2O3 4 mole Fe O2 and Fe2O3 3 mole O2 and 2 mole Fe2O3 2 mole Fe2O3 3 mole O2 LecturePLUS Timberlake 99

Learning Check S1 3 H2(g) + N2(g) 2 NH3(g) A. A mole factor for H2 and N2 is 1) 3 mole N22) 1 mole N2 3) 1 mole N2 1 mole H2 3 mole H2 2 mole H2 B. A mole factor for NH3 and H2 is 1) 1 mole H2 2) 2 mole NH3 3) 3 mole N2 2 mole NH3 3 mole H2 2 mole NH3 LecturePLUS Timberlake 99

Solution S1 3 H2(g) + N2(g) 2 NH3(g) A. A mole factor for H2 and N2 is 2) 1 mole N2 3 mole H2 B. A mole factor for NH3 and H2 is 2) 2 mole NH3 3 mole H2 LecturePLUS Timberlake 99

Chemical Calculations 4 Fe + 3 O22 Fe2O3 How many moles of Fe2O3 are produced when 6.0 moles O2 react? 6.0 mole O2 x 2 mole Fe2O3 = 4.0 mole Fe2O3 3 mole O2 LecturePLUS Timberlake 99

Learning Check S2 4 Fe + 3 O2 2 Fe2O3 How many moles of Fe are needed to react with 12.0 mole of O2? 1) 3.00 mole Fe 2) 9.00 mole Fe 3) 16.0 mole Fe LecturePLUS Timberlake 99

Solution S2 4 Fe + 3 O2 2 Fe2O3 12.0 mole O2 x 4 mole Fe = 16.0 mole Fe 3 mole O2 LecturePLUS Timberlake 99

Learning Check S 3 4 Fe + 3 O2 2 Fe2O3 How many grams of O2 are needed to produce 0.400 mole of Fe2O3? 1) 38.4 g O2 2) 19.2 g O2 3) 1.90 g O2 LecturePLUS Timberlake 99

Solution S 3 2) 19.2 g O2 0.400 mole Fe2O3 x 3 mole O2 x 32.0 g O2 2 mole Fe2O3 1 mole O2 = 19.2 g O2 LecturePLUS Timberlake 99

Mass of A Reaction The reaction between H2 and O2 produces 13.1 g of water. How many grams of O2 reacted? Write the equation H2 (g) + O2 (g) H2O (g) Balance the equation 2 H2 (g) + O2 (g) 2 H2O (g) LecturePLUS Timberlake 99

Organize data mole bridge 2 H2 (g) + O2 (g) 2 H2O (g) ? g 13.1 g Plan g H2O mole H2O mole O2 O2 Setup 13.1 g H2O x 1 mole H2O x 1 mole O2 x 32.0 g O2 18.0 g H2O 2 mole H2O 1 mole O2 = 11.6 g O2 LecturePLUS Timberlake 99

Points to Remember 1. Read an equation in moles 2. Convert given amount to moles 3. Use mole factor to give desired moles 4. Convert moles to grams grams (given) grams (desired) moles (given) moles (desired) LecturePLUS Timberlake 99

Learning Check S 4 How many grams of O2 are need to react 50.0 grams of Na in the reaction 4 Na + O2 2 Na2O Complete the set up: 50.0 g Na x 1 mole Na x ________ x _______ 23.0 g Na LecturePLUS Timberlake 99

Solution S 4 4 Na + O2 2 Na2O 50.0 g Na x 1 mole Na x 1 mole O2 x 32.0 g 23.0 g Na 4 mole Na 1 mole O2 = g O2 LecturePLUS Timberlake 99

Learning Check S5 Acetylene gas C2H2 burns in the oxyactylene torch for welding. How many grams of C2H2 are burned if the reaction produces 75.0 g of CO2? 2 C2H2 + 5 O2 4 CO2 + 2 H2O LecturePLUS Timberlake 99

Solution S5 2 C2H2 + 5 O2 4 CO2 + 2 H2O 75.0 g CO2 x 1 mole CO2 x 2 mole C2H2 x 26.0 g C2H2 44.0 g CO2 4 mole CO2 1 mole C2H2 = 22.2 g C2H2 LecturePLUS Timberlake 99

Pathways for Problems Using Equations Given (A) Find (B) grams (A) grams (B) moles (A) moles (B) particles (A)particles (B) LecturePLUS Timberlake 99

Pathways for Problems Using Equations Given (A) Find (B) grams (A) grams (B) molar molar mass (A) mass (B) coefficients moles (A) moles (B) Avogadro's Avogradro’s number number particles (A)particles (B) LecturePLUS Timberlake 99

Chapter 5 Chemical Reactions and Quantities