Chemistry for Engineering Students
3rd Edition
ISBN: 9781285199023
Author: Lawrence S. Brown, Tom Holme
Publisher: Cengage Learning
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Chapter 4, Problem 4.38PAE
4.36 Sometimes students in chemistry labs determine percentage yields greater than 100%. Assuming there is no calculation error, how could this happen?
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The concepts of stoichiometry are similar to those in a cooking recipe. For example, suppose we use the following pizza recipe:
1 crust + 5 ounces tomato sauce + 2 cups cheese --> 1 pizza
The recipe contains the numerical relationship between the pizza ingredients. It says that if we have 2 cups of cheese -- and enough of everything else -- we can make 1 pizza. We can write this relationship as a ratio between the cheese and the pizza.
2 cups cheese : 1 pizza
1) How many pizzas can we make if we have 6 cups of cheese? Assuming that we have enough of everything else. Show work by using the ratio as a conversion factor to calculate the number of pizzas.
2) Suppose that we have 4 crusts, 15 ounces of tomato sauce, and 10 cups of cheese theoretically. How many pizzas can we make?
3) Which one of three ingredients in the above case can give the least amount of pizzas?
4) If this were a chemical reaction, what is the theoretical yield in…
Now we will examine a more complex system. Watch the animation portraying the combustion of propane. The unbalanced chemical equation is
given below.
_C;Hg(g) + _O2(g) → _CO2(g) + _H,O(E)
Begin by balancing an element that appears in the fewest different formulas. What coefficient must be added to the CO2 to balance the element C?
Balance the following chemical equation and determine the number of moles of Fe(s) produced when 1 moles of Fe203(s) react
with excess C(s) to produce Fe(s) and CO2(g).
Fe203(s) + C(s) → Fe(s) + CO2(g)
O Respond with the correct number of significant figures in scientific notation (Use E notation and only 1 digit before decimal e.g. 2.5E5 for 2.5 x 105)
Chapter 4 Solutions
Chemistry for Engineering Students
Ch. 4 - Describe the chemical composition of gasoline.Ch. 4 - Write balanced chemical equations for the...Ch. 4 - Prob. 3COCh. 4 - Calculate the amounts of reactants needed in a...Ch. 4 - Prob. 5COCh. 4 - Prob. 6COCh. 4 - Prob. 7COCh. 4 - 4.1 List at least two factors that make it...Ch. 4 - 4.2 What is an alkane?Ch. 4 - 4.3 Explain the difference between complete and...
Ch. 4 - 4.4 Automobile exhaust often contains traces of...Ch. 4 - 4.5 Methane, ethane, and propane are also...Ch. 4 - 4.6 Use the web to research prices of gasoline at...Ch. 4 - For the following reactions, write the ratios that...Ch. 4 - 4.8 In an experiment carried out at very low...Ch. 4 - 4.9 Sulfur, S8, combines with oxygen at elevated...Ch. 4 - 4.10 How many moles of oxygen can be obtained by...Ch. 4 - 4.11 MTBE, C5H12O, is one of the additives that...Ch. 4 - 4.12 In petroleum refining, hydrocarbons are often...Ch. 4 - 4.13 For the following reactions, determine the...Ch. 4 - 4.14 The combustion of liquid chloroethylene,...Ch. 4 - 4.15 What mass of the unknown compound is formed...Ch. 4 - 4.16 Many metals react with halogens to give metal...Ch. 4 - 4.17 Phosgene is a highly toxic gas that has been...Ch. 4 - Prob. 4.18PAECh. 4 - 4.19 How many metric tons of carbon are required...Ch. 4 - 4.20 Assuming a charcoal briquette is composed...Ch. 4 - 4.21 Ammonium nitrate, NH4NO3, will decompose...Ch. 4 - If 3.4 mol Al and 6.2 mol Fe2O3 are mixed, what is...Ch. 4 - If 8.4 moles of disilane, Si2H6, is combined with...Ch. 4 - 4.22 Generally, an excess of O2 is needed for the...Ch. 4 - 4.23 In the reaction of arsenic with bromine,...Ch. 4 - 4.24 Ammonia gas can be prepared by the reaction...Ch. 4 - 4.25 When octane is combusted with inadequate...Ch. 4 - 4.26 The equation for one of the reactions in the...Ch. 4 - 4.27 Copper reacts with sulfuric acid according to...Ch. 4 - 4.28 One of the steps in the manufacture of nitric...Ch. 4 - 4.29 When Al(OH)3 reacts with sulfuric acid, the...Ch. 4 - 4.30 Copper reacts with nitric acid via the...Ch. 4 - 4.31 How much HNO3 can be formed in the following...Ch. 4 - 4.32 Hydrogen and oxygen are reacted and the water...Ch. 4 - 4.33 Silicon carbide, an abrasive, is made by the...Ch. 4 - Prob. 4.36PAECh. 4 - Prob. 4.37PAECh. 4 - 4.36 Sometimes students in chemistry labs...Ch. 4 - 4.37 The theoretical yield and the actual yield...Ch. 4 - 4.38 A reaction that produced 4.8 mg of taxol, an...Ch. 4 - Methanol, CH3OH, is used in racing cars because it...Ch. 4 - 4.40 When iron and steam react at high...Ch. 4 - 4.41 The percentage yield of the following...Ch. 4 - 4.42 Sulfur hexafluoride is a very stable gas...Ch. 4 - 4.43 Magnesium nitride forms in a side reaction...Ch. 4 - 4.44 Industrial production of hydrogen gas uses...Ch. 4 - 4.45 If 21 g of H2S is mixed with 38 g of O2 and...Ch. 4 - 4.46 A mixture of 10.0 g of NO and 14.0 g of NO2...Ch. 4 - 4.47 Silicon carbide is, an abrasive used in the...Ch. 4 - 4.48 Elemental phosphorous is used in the...Ch. 4 - 4.49 Small quantities of hydrogen gas can be...Ch. 4 - Prob. 4.52PAECh. 4 - 4.51 What is the role of an indicator in a...Ch. 4 - 4.52 What volume of 0.812 M HCl, in milliliters,...Ch. 4 - Prob. 4.55PAECh. 4 - Prob. 4.56PAECh. 4 - Hydrazine, N2H4, is a weak base and can react with...Ch. 4 - Prob. 4.58PAECh. 4 - Prob. 4.59PAECh. 4 - Prob. 4.60PAECh. 4 - 4.59 Aluminum dissolves in HCI according to the...Ch. 4 - 4.60 Why are fuel additives used?Ch. 4 - 4.61 What is actually measured by the octane...Ch. 4 - Prob. 4.64PAECh. 4 - Prob. 4.65PAECh. 4 - 4.64 Using the web, find information about the...Ch. 4 - 4.65 Using the web, find out how lead “poisons”...Ch. 4 - Prob. 4.68PAECh. 4 - You have 0.954 g of an unknown acid, H2A, which...Ch. 4 - Prob. 4.70PAECh. 4 - 4.79 Phosphoric add (H3PO4) is important in the...Ch. 4 - 4.80 The reaction shown below is used to destroy...Ch. 4 - Prob. 4.73PAECh. 4 - One way of determining blood alcohol levels is by...Ch. 4 - Prob. 4.75PAECh. 4 - The pictures below show a molecular-scale view of...Ch. 4 - The pictures below show a molecular-scale view of...Ch. 4 - 4.84 Aluminum chloride (AlCl3) is used as a...Ch. 4 - 4.85 In the cold vulcanization of rubber, disulfur...Ch. 4 - Prob. 4.80PAECh. 4 - Prob. 4.81PAECh. 4 - 4.88 A quality control technician needs to...Ch. 4 - Prob. 4.83PAECh. 4 - 4.90 Iron metal can be refined (rom the mineral...Ch. 4 - Prob. 4.85PAECh. 4 - Prob. 4.86PAECh. 4 - 4.93 A mixture of methane (CH4) and propane (C3H8)...Ch. 4 - Prob. 4.88PAECh. 4 - Prob. 4.89PAECh. 4 - Prob. 4.90PAECh. 4 - Prob. 4.91PAECh. 4 - Prob. 4.92PAECh. 4 - Prob. 4.93PAECh. 4 - Prob. 4.94PAECh. 4 - Prob. 4.95PAECh. 4 - Prob. 4.96PAECh. 4 - Prob. 4.97PAECh. 4 - 4.104 When 2.750 g of the oxide Pb3O4 is heated to...Ch. 4 - Prob. 4.99PAECh. 4 - 4.106 An ore sample with a mass of 670 kg contains...Ch. 4 - 4.107 Existing stockpiles of the refrigerant...Ch. 4 - 4.108 Elemental analysis is sometimes carried out...Ch. 4 - Prob. 4.103PAECh. 4 - 4.110 Write the balanced chemical equation lot the...Ch. 4 - 4.111 Aluminum metal reacts with sulfuric acid to...Ch. 4 - 4.112 A metallurgical firm wishes to dispose of...
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