CHAPTER 3 – STOICHIOMETRY OF EQUATION
Part II: Section 3.4
1.
2.
3.
4.
5.
6.
Define chemical reaction, and list the reactants and products in a given reaction.
Use the correct symbols for the physical state of each substance involved in a chemical equation.
Distinguish subscripts and coefficients and write a balanced equation given names and /or
formulas for reactants and products.
Use a balanced equation to relate the numbers of moles or grams of reactants and products.
Given the numbers of moles or grams of each reactant, determine the limiting reactant and
calculate the theoretical yield of product.
Relate the actual yield of product to the theoretical yield and percent yield.
WRITTEN ASSIGNMENTS:
TOPIC
Balancing equations
Mass relations in Reactions
Unclassified and Conceptual
PAGE #
QUESTION(S) #
79
79
81
48-52
54-60; 64-68 all even
74, 78, 80
Packet: as assigned.
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CHAPTER 3 – STOICHIOMETRY OF EQUATION
Begin each problem by sketching a diagram that outlines the steps in the solution to the problem.
Show all work.
1.
Given the following balanced equation: P4(s) + 5O2(g) ------ > P4O10(g)
Find:
a. the number of atoms of phosphorus that will combine with 200 molecules of O2.
b. the number of molecules of P4O10 that will form from 2 x 108 molecules of O2 and sufficient P4.
2.
Given the following balanced equation 2NO(g) + O2(g) ---- > 2NO2(g)
Find
b. How many moles of NO2 are formed from 0.25 mole of NO and sufficient O2.
c. How many moles of O2 are left over if 80 moles of NO is mixed with 200 moles of O2 and the
mxture reacts?
3.
Given the following balanced eqaution C3H8(g) + 5O2(g) ----- > 3CO2(g) + 4H2O(g)
Find:
a. How many liters of oxygen, O2, are needed to produce 600 liters of carbon dioxide, CO2 at
STP?
b. How many milliliters of propane, C3H8, will react with 280 milliliters of oxygen, O2?
4.
Given the following equation, Mg(s) + 2HCl(aq) ----- > MgCl2(aq) + H2(g). Find
a. How many grams of magnesium, Mg, are needed to produce 100 grams of hydrogen, H2(g)?
b. How many grams of hydrogen chloride, HCl, is needed to produce 200 grams of hydrogen,
H2?
5.
One of the steps in the production of iron utilizes the following chemical reaction:
3CO(g) + Fe2O3(s) ----- > 2Fe(s) + 3CO2(g)
a. W hat mass of Fe2O3 would react with 500 liters of CO at STP?
b. W hat volume of CO2 at STP is produced from 1000 grams of Fe2O3?
c. W hat mass if iron is produced when 300 mL of CO2 is produced at STP?
1. a. 160 atoms; b. 4x107 molec
4. a. 1.20x103 g; b. 7.23x103 g
2 . b . 0 .2 5 m o l ; c . 1 6 0 m o l
3. a. 1.00x103 L; b. 56.0 mL
3
5 . a . 1 .1 9 x 1 0 g ; b . 4 2 0 L ; c . 0 .4 9 8 g
Limiting Reactant
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CHAPTER 3 – STOICHIOMETRY OF EQUATION
1.
For each of these balanced equations, identify the limiting reagent for the given combination of
reactants:
a.
O2(g) → 2H2O
2.3 mol
2H2(g) +
5.0 mol
b. 4P
+
7.0 mol
5O2 → 2P2O5
8.0 mol
c. 2Al
+ 3Cl2 → 2AlCl3
5.4 mol
8.0 mol
d.
2P2O5
7.5 mol
+
6H2O →4H3PO4
3.9 mol
2.
Acetylene, C2H2, will burn in the presence of oxygen. 2C2H2(g) + 5O2(g) → 4CO2(g) +
2H2O(l)
How many grams of water can be produced by the reaction of 4.80 mol of C2H2 with 14.8 mol of
O2?
3.
Sodium chloride can be prepared by the reaction of sodium metal with chlorine gas.
2Na(s) + Cl2(g) → 2NaCl(s)
W hen 6.70 mol of Na reacts with 3.20 mol of Cl2:
a. W hat is the limiting reactant?
b. How many moles of NaCl are produced?
c. How much of the excess reagent will react?
d. How much of the excess reactant will remain imtack after the reaction?
4.
Copper reacts with sulfur to form copper(I) sulfide.
a. W hat is the limiting reactant when 80.0 g of Cu reacts with 25.0 g of S?
b. How many grams of Cu2S can be formed in the above reaction?
c. How much of the excess reactant did react?
d. How much of the excess reactant remained after the reaction?
5.
Hydrogen gas can be produced in the laboratory by the reaction of magnesium metal with
hydrochloric acid.
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
a. How many grams of hydrogen can be produced when 4.00 g of HCl is added to 3.00 g of Mg?
b. How many grams of the excess reactant will remain after the reaction?
1. a)O2; b) O2; c) Cl2; d) H2O
3. a) Cl2, b) 6.40 mol of NaCl, c) 6.40 mol Na; d) 0.30 mol Na
4. a) Cu; b) 100. G Cu2S; c) 20.2 g S; d) 4.85 g S
2. 86.4 g H2O
5. A) 0.110g H2; b) 1.68 g Mg
Limiting Reactant (Extra Practice)
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CHAPTER 3 – STOICHIOMETRY OF EQUATION
Begin each problem by sketching a diagram that outlines the steps in the solution to the problem.
Show all work.
1.
If 2.50 mol of copper and 5.50 mol silver nitrate are available to react by single replacement,
a. write a balanced equation for the reaction
b. identify the limiting reactant
c. determine the number of moles of each product formed
d. determine the number of moles of excess reactant remaining
e. determine the theoretical yield, in grams, of each product formed.
2.
A gaseous mixture containing 7.50 mol H2(g) and 9.0 mol Cl2(g) reacts to form hydrogen chloride
gas.
a. W rite a balanced equation for the reaction.
b. W hich reactant is limiting?
c. If all the limiting reactant are consumed, how many moles of hydrogen chloride are formed?
d. How many moles of excess reactant remain unchanged?
d. Calculate the mass of the limiting reactant that reacted.
3.
Sodium reacts with water to form sodium hydroxide and hydrogen gas.
a. If 90.0 grams of sodium is dropped into 80.0 g of water, how many liters of hydrogen at STP
could be produced?
b. W hich reactant is in excess and how much of it is left over?
4.
The coating you see on a corroded iron object that has been left in moist soil is black iron oxide,
Fe3O4. This substance can also be made by:
3Fe(s) + 4 H2O(l) -----> Fe3O4 (s) + 4H2(g)
a. Balance the equation
b. W hen 36.0 g of H2O reacts with 167 g of Fe, which is the limiting reactant?
c. How much of the excess reactant is not used when the reaction is completed?
d. W hat is the theoretical yield of black iron oxide?
1. Cu, 2.50 mol Cu(NO3)2, 5 mol silver, 0.5 mol of AgNO3, 473.25 Cu(NO3)2, 540 Ag.
2. H2, 15 mol HCl, 1.,5 mol H2,
3. 43.8 L, H2O, 9.6 g excess
4. H2O; 83.3 g, 116 g.
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CHAPTER 3 – STOICHIOMETRY OF EQUATION
Percent Yield
Begin each problem by sketching a diagram that outlines the steps in the solution to the
problem. Show all work.
1.
Methanol can be produced through the reaction of CO and H2 in the presence of a catalyst
CO(g) + H2(g) → CH3OH(l)
If 75.0 g of CO reacts to produce 68.4 g CH3OH, what is the percent yield of CH3OH?
2.
Aluminum reacts with excess CuSO4. If 1.85 g Al react and the percent yield of Cu is 56.6%,
what mass of Cu is produced?
3.
Quicklime, CaO, can be prepared by the reaction CaCO3 ----> CaO + CO2.
W hen 2.00 x 103 g of CaCO3 are heated, the actual yield of CaO is 1.0 x 103 g. W hat is the
percent yield?
4.
The Ostwald Process for producing nitric acid from ammonia consists of the following steps:
4NH3 + 5O2 -→ 4NO + 6H2O
2NO + O2 → 2NO2
3NO2 + H2O → 2HNO3 + NO
If the yield in each step is 80%, how many grams of nitric acid can be produced from 5.00 kg of
ammonia?
1 . 7 9 .8 %
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2 . 3 .7 0 g
3 . 8 9 .3 %
4. 6.32 x 103g HNO3
5
CHAPTER 3 – STOICHIOMETRY OF EQUATION
Equation Stoichiometry – Review(1)
1.
An excess of sulfuric acid reacts with 165 g of barium peroxide. (a) How many moles of hydrogen
peroxide are produced? (b) How many moles of barium sulfate?
2.
A mass of 134 g of zinc was added to a solution containing 100. g HCl. After the reaction ceased, 41 g of
zinc remained. How many moles of hydrogen were produced?
3.
A mixture of 10.0 g of powdered iron and 10.0 g of sulfur is heated to its reaction temperature in an open
crucible. (a) How many grams of iron(II) sulfide are formed? (b) The reactant in excess is oxidized How
many grams of its oxide are formed?
4.
How many grams of air are required to complete the combustion of 93 g of phophorus to diphosporus
pentoxide, assuming the air to be 23% oxygen by mass?
5.
(a) What mass of H2SO4 in grams is required in a reaction with an excess of aluminum to produce 0.50
mole of aluminum sulfate? (b) How many moles of hydrogen are also produced?
6.
A certain rocket uses butane, C4H10, as fuel. How many kilograms of liquid oxygen should be carried for
the complete combustion of each 1.00 kg of butane to carbon dioxide and water vapor?
7.
Acetylene gas, C2H2, burns in oxygen and forms carbon dioxide and water vapor. (a) How many liters of
oxygen gas at STP are needed to burn 15.0 L of acetylene? (b) How many liters of carbon dioxide gas at
STP are formed? How many moles of water at STP are produced?
8.
Ethane gas, C2H6, burns in air and produces carbon dioxide and water vapor. (a) How many liters of
carbon dioxide gas are formed when 20.0 L of ethane is burned? (b) How many moles of water at STP are
formed?
9.
How many liters of air are required to furnish the oxygen gas to complete the reaction in Problem 8?
(Assume the air to be 20.9% oxygen by volume.)
10.
If 250. mL of hydrogen gas and 200 ml of oxygen gas are mixed and ignited, what volume of oxygen gas
remains uncombined?
11.
(a) How many liters of hydrogen gas at STP are required to convert 22.5 g of hot copper(II) oxide to
metallic copper?
(b) How many moles of water are formed under the same conditions?
12.
When 125 g of zinc reacts with 125 g of HCl, how many liters of hydrogen are formed? ( Note: Limiting
reactant?)
13.
How many liters of hydrogen gas at STP will be produced by the reaction of 15.0 g of calcium metal and
excess hydrochloric acid? Calcium chloride is the other product?
1. 0.975 mol H2O2 , 0.975 mol BaSO4
2. 1.37 mol H2
4. 520 g air
5. 150g HSO4, 1.5 mol H2O
7. 37.5 L O2, 30.0 L CO2, 0.670 mol H2O 8. 40.0 L CO2, 2.68 mol H2O
10. 75 mL uncombined
11. 6.33 L H2, 0.283 mol H2
1 3 . 8 . 3 8 L H2
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3. 15.8 g FeS, 5.79 g S, 8.4 g SO2
6. 3.59 kg O2
9. 335 L air
1 2 . 3 8 . 4 L H2
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CHAPTER 3 – STOICHIOMETRY OF EQUATION
Equation Stoichiometry - Review(2)
1. What mass in grams of calcium hydroxide can be produced from 1.20 kg of limestone, calcium carbonate?
(Decomposition of calcium carbonate with heat yields calcium oxide and carbon dioxide. Calcium
hydroxide is formed by the reaction of calcium oxide and water.)
2. How many metric tons of carbon dioxide can be produced from the combustion of 5.00 metric tons of coke
that is 85.5% carbon? 1 metric ton = 1000 kg
3. When a mass of 85 g of ethane gas, C2H6, is burned completely in air, carbon dioxide and water vapor are
formed. (a) How many moles of carbon dioxide are produced? (b) How many moles of water are
produced?
4.
(a) How many grams of sodium sulfate are produced in the reaction between 150. g of sulfuric acid and
excess of sodium chloride? (b) How many grams of sodium chloride are used? How many grams of
hydrogen chloride are also produced?
5. How many liters of hydrogen and nitrogen are required to produce 30. L of ammonia gas?
6. Carbon monoxide burns in oxygen and forms carbon dioxide. (a) How many liters of carbon dioxide are
produced when 25 L of carbon monoxide burns? (b) How many liters of oxygen are required?
[
7. Acetylene gas, C2H2, burns in oxygen and forms carbon dioxide and water vapor. (a) How many liters of
oxygen are needed to burn 15.0 L of acetylene? (b) How many liters of carbon dioxide are formed? c)
How many moles of water are produced?
8. How many grams of sodium are needed to release 1.5 L of hydrogen from water?
9. (a) How many liters of oxygen can be produced by the electrolysis of 75.0 g of water? (b) How many
liters of hydrogen are produced simultaneously?
10. How many grams of copper will be produced when hydrogen reacts with 50.0 g of hot copper(II) oxide?
(b) How many liters of hydrogen are required? © How many moles of water are formed
11. Zinc reacts with dilute sulfuric acid to form hydrogen and zinc sulfate in solution. If 8.00 g of zinc reacts
with excess sulfuric acid, (a) what volume of hydrogen is liberated? (b) What mass of zinc sulfate is
formed?
1.[ 888 g
2. 15.7 metric ton CO2 3. 5.7 mol CO2, 8.5 mol H2O
4. 217 g Na2SO4, 179 g NaCl, 112 g HCl 5. 15 L N2, 15 L NH3
6. 25 L CO2, 12.5 L O2
7. [ 37.5 L O2, 30.0 L CO2, 0.670 mol H2O
8. 3.1 g Na
9. 46.7 L O2, 93.3 L H2
12. 10. 39.9 g Cu, 14.1 L H2, 0.629 mol H2O
11. 2.74 L H2, 19.8 g ZnSO4
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CHAPTER 3 – STOICHIOMETRY OF EQUATION
Stoichiometry - Miscellaneous Problems
1.
CS2 + 3O2 →CO2 + 2SO2. How many cubic centimeters at STP of SO2 will be produced by burning
3.0 g of CS2?
2.
FeS + 2HCl → H2S + FeCl2. How many grams of FeS are needed to produce 100. g of H2S? W hat
volume does this H2S occupy at STP?
3.
2KClO3 →2KCl + 3O2. How many liters at STP of oxygen will be produced by decomposing 25 g of
KClO3?
4.
In the contact process for the production of sulfuric acid, the sulfur present in FeS2 is eventually converted
into H2SO4. Assuming that the conversion is complete, how many kilograms of H2SO4 may be made from
2.0 tons of FeS2?
5.
If the H2SO4 produced in the preceding problem has a density of 1.86 g/cm3 what volume will it occupy?
6.
2C4H10 + 13O2 →8CO2 + 10H2O. How many milliliters at STP of CO2 can be produced from 15 cm3
of liquid butane, C4H10? The density of liquid butane is 0.60 g/cm3.
7.
A CaCl2 solution with a mass of 50.0 grams contains 30.0% CaCl2. This solution reacts with 35.0 grams
of AgNO3, one of the products is the precipitate, AgCl. Calculate the following:
a. the excess material and the grams of excess material.
b. the moles of AgCl produced.
c. the grams of Ca(NO3)2 produced.
8.
In the reaction between hydrogen gas and nitrogen gas to produce ammonia, 50.0 dm3 of hydrogen (d=
0.0900 g/liter) react with 15.0 dm3 of nitrogen (d= 1.25 g/L). Calculate the grams of ammonia ( d= 0.759
g/L) produced if the yield is 35.0% of ammonia.
9.
A solution containig 20.0 grams of sodium sulfite reacts with 7.00 cm3 of phophoric acid (d=1.83 g/cm3).
Determine the following:
a. the excess reactant and its mass.
b. grams of water produced.
c. moles of sodium phosphate produced.
d. grams of sulfur dioxide produced.
e. cubic decimeters of sulfur dioxide at STP.
1.
6.
8.
c.
1.8 L 2. 258 g; 65.9L
3 . 6 .9 L 4 . 3 .3 x 1 0 6 g
5. 1.76 x 106 cm3
14 Liters
7. CaCl2; 3.51 g excess; 0.207 moles AgCl; 16.9 g Ca(NO3)2
22.8 g NH3(100%); 7.98 g (35%)
9. a H3PO4; 10.4 g reacted; 2.43 g excess; b. 2.86 g H2O
5.67 x 10-4 moles Na3PO4; d. 10.2 g SO2; e. 3.56 L SO2
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CHAPTER 3 – STOICHIOMETRY OF EQUATION
Challenge
Begin each problem by sketching a diagram that outlines the steps in the solution to the
problem. Show all work.
1.
Calculate the grams of air required for the complete combustion of 50.0 mL ethanol ( C2H5OH, density
0.789 g/mL). The products are water and carbon dioxide. Assume that the air contains 20.0% oxygen by
mass.
2.
How many grams of zinc chloride solution are required to react with 15.0 grams of aluminum metal? The
products are aluminum chloride and zinc metal. Assume that the zinc chloride solution contains 8.00% pure
zinc chloride by mass.
3.
From the overall reaction, determine the milliliters of sulfuric acid ( density 1.83 g/mL) consumed if 5.00
grams of lead(II) sulfate are formed during the discharging of an automobile lead cell storage battery.
Pb(s) + PbO2(s) + H2SO4(aq) → PbSO4(s) + H2O(l)
4.
A detergent, sodium dodecanesulfonate, C12H25OSO3Na, is made by the successive reactions of sulfuric
acid and sodium hydroxide on dodecanol, C12H25OH. If any manufacturer needs to produce 30.0 metric
tons of detergent daily, how many metric tons of dodecanol are needed? Assume the reaction is complete
and there is no waste. ( 1 metric ton = 1000 kg).
5.
Nitric acid is used to dissolve completely a 10.0 gram silver coin. Upon the addition of sodium chloride
solution, all the silver is precipitated as silver chloride. If 12.0 grams of AgCl are obtained, what is the
percentage of silver in the coin?
6.
Molten iron and carbon monoxide are produced in a blast furnace by the reaction of iron(III) oxide and coke
(carbon). If 25.0 kilograms of pure Fe2O3 are used, how many moles of iron can be produced?
7.
How much limestone must be decomposed by heating to produce 250.0 grams of lime, CaO? Assume that
the limestone contains 95.0% pure CaCO3.
8.
Ammonia gas produced as a by-product in an industrial reaction can react with sulfuric acid in order that the
gas does not escape into the atmosphere. The product, ammonium sulfate, can be used as a fertilizer.
Determine how many kilograms of acid are required to produce 1000.0 kilograms of (NH4)2SO4.
9.
Coal gasification is a process which is carried out industrially in a series of steps. However, the net reaction
involves coal, C, reacting with water to form methane, CH4, and carbon dioxide. How many kilograms of
methane can be produced from 1000.0 kilograms of coal?
10.
A source of “acid rain” is automobile exhaust. Nitrogen monoxide, formed in an internal combustion engine,
reacts with oxygen in the air to produce nitrogen dioxide. The NO2 reacts with water to form nitric acid. It is
determined that the average car produces 10.0 cubic meters of exhaust gas per mile driven. Assume that
the average concentration of NO in auto exhaust is 100.0 ug/m3 and that traffic surveys have shown an
average of 2.00 x 106 vehicle miles driven per day. From this data, determine the kilograms of nitric acid
which would be produced annually.
1. 411 g air
5. 90.2% AgCl
9. 667 kg coal
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2. 1420 g ZnCl2 solution
6. 313 mol
10. 766 kg HNO3
3. 0.884 mL
7. 469 g limestone
4. 19.4 metric tons
8. 742.24 kg H2SO4
9