CHM 1025C Name: _________________
Module Five III Homework Packet
Module Five Part III: Chemical Equations & Stoichiometry (Chapter 9)
L._____ (05) Per Cent Yield Problems/Impure Reagents-Section 9.9
Module Five III Chapter 9 Sections
see worked Example 9.2 page 253
additional Suggested Problems: Pages 273-274 #7-12
Part I Mole-Mole Stoichiometry 10 points
Homework #1: Tungsten occurs in the important mineral sheelite (Calcium tungstate), which is converted to tungstic acid. Tungsten is then extracted from tungstic acid by the following (unbalanced) reaction:
H2 + H2WO4 à W + H2O
How moles of hydrogen is needed to prepare 6 moles of elemental tungsten?
Homework #2: Phosphoric acid can be made by the following (unbalanced) reacti
H2O + P4O10 à H3PO4
How many moles of Phosphoric acid can be prepared from the combination of 5 moles of Tetraphosphorus decoxide with excess water?
Module Five III Chapter 9 Sections 9.4
see worked Examples 9.4 page 256 and 9.5 page 257
additional Suggested Problems: Page 274 #19-28
Part J Mass-Mass Stoichiometry 10 points
Homework #3: Toluene and nitric acid are used in the production of trinitrotoluene (TNT), an explosive:
C7H8 + HNO3 à C7H5N3O6 + H2O (Unbalanced)
Calculate the mass of TNT that can be made from 192 g of C7H8 (toluene).
Homework #4: What mass of carbon dioxide is produced from the combustion of 176 grams of propane gas , C3H8 , in excess oxygen gas, O2. Water is the only other product.
Skip Sections 9.5 and 9.6 until Module 6
Five III Chapter 9 Sections 9.7-9.8
see worked Examples 9.9 page 265 and 9.10 page 267
additional Suggested Problems: Page 275-6 Concept #49-58-Problems #59-74
Part K Excess-Limiting Reagent Problem 5 points
Homework #5: How many grams of Calcium phosphate can be made according to the reaction (unbalanced):
CaCl2 + K3PO4 ----> Ca3(PO4)2 + KCl
by mixing a solution of 5.00 grams of CaCl2 with another containing 8.00 grams of Potassium phosphate?
Five III Chapter 9 Sections 9.9
see worked Examples 9.12 page 270-271
additional Suggested Problems: Page 276-7 #75-78
Part L Impure Reagents/Percent Yield Problem 5 points
Homework #6: A laboratory manual calls for 13.0 grams of butanol reactant in excess sodium bromide and sulfuric acid as reactants in this reaction:
C4H9OH + NaBr + H2SO4 ------> C4H9Br + NaHSO4 + H2O
A student following these directions obtains 16.8 grams of butyl bromide (C4H9Br). What is the theoretical yield and the percent yield of this reaction?