CHM 1025C Name: _________________
Module Five III Homework Packet

Module Five Part III: Chemical Equations & Stoichiometry (Chapter 9)

I.______(10) Mole-Mole Problems Sections 9.1-9.2 Answers ij

J._____ (10) Mass-Mass Stoichiometric Problems-Sections 9.3 & 9.4 Answers ij

K._____(05) Excess/Limiting Reagent Problems-Section 9.7-9.8 Answers kl

L._____ (05) Per Cent Yield Problems/Impure Reagents-Section 9.9

______(30) Total

Module Five III Chapter 9 Sections 9.1-9.2
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 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 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 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

Module 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?

 

 

 

 

 

 

Module 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?