Chapter 03 – Mass Relationships in Chemical Reactions
92. What is the coefficient of O2 when the following equation is properly balanced?
___ CH3OH + ___ O2 → ___ CO2 + ___ H2O
93. Balance the following equation and list the coefficients in order from left to right.
__ SF4 + __ H2O → __ H2SO3 + __ HF
Chapter 03 – Mass Relationships in Chemical Reactions
94. Balance the following and list the coefficients in order from left to right.
___ Cr + ___ H2SO4 → ___ Cr2(SO4)3 + ___ H2
95. Lithium metal reacts with nitrogen gas to form lithium nitride. Identify the balanced
reaction that describes this process.
Chapter 03 – Mass Relationships in Chemical Reactions
96. Ammonia reacts with hydrochloric acid to produce ammonium chloride. Identify the
balanced reaction that describes this process.
97. Iron metal reacts with hydrochloric acid to produce iron (II) chloride and hydrogen gas.
Identify the balanced reaction that describes this process.
Chapter 03 – Mass Relationships in Chemical Reactions
98. Aluminum metal reacts with nitric acid to produce aluminum nitrate and hydrogen gas.
Identify the balanced reaction that describes this process.
99. Ammonia reacts with oxygen to form nitric oxide and water vapor:
4NH3 + 5O2 → 4NO + 6H2O
When 40.0 g NH3 and 50.0 g O2 are allowed to react, which is the limiting reagent?
Chapter 03 – Mass Relationships in Chemical Reactions
100. Ammonia reacts with oxygen to form nitric oxide and water vapor:
4NH3 + 5O2 → 4NO + 6H2O
When 20.0 g NH3 and 50.0 g O2 are allowed to react, which is the limiting reagent?
101. When 22.0 g NaCl and 21.0 g H2SO4 are mixed and react according to the equation
below, which is the limiting reagent?
2NaCl + H2SO4 → Na2SO4 + 2HCl
Chapter 03 – Mass Relationships in Chemical Reactions
102. Vanadium(V) oxide reacts with calcium according to the chemical equation below.
When 10.0 moles of V2O5 are mixed with 10.0 moles of Ca, which is the limiting reagent?
V2O5(s) + 5Ca(l) → 2V(l) + 5CaO(s)
103. Chlorine gas can be made from the reaction of manganese dioxide with hydrochloric
acid.
MnO2(s) + 4HCl(aq) → MnCl2(aq) + 2H2O(l) + Cl2(g)
According to the above reaction, determine the limiting reactant when 5.6 moles of MnO2 are
reacted with 7.5 moles of HCl.
Chapter 03 – Mass Relationships in Chemical Reactions
104. Sulfur dioxide gas reacts with oxygen gas and water according to the chemical reaction
below. When 4.5 g of SO2 are mixed with excess O2 and H2O, how many grams of H2SO4 are
produced?
2SO2(g) + O2(g) + 2H2O(l) → 2H2SO4(l)
105. Chlorine gas reacts with phosphorus to produce phosphorus pentachloride. How many
grams of PCl5 are produced from 3.5 g of Cl2 and excess P?
5Cl2(g) + 2P(s) → 2PCl5(s)
Chapter 03 – Mass Relationships in Chemical Reactions
106. Phosphorus pentachloride reacts with water to form hydrochloric acid and phosphoric
acid. How many total moles of acid are formed when starting with 4.5 g of PCl5 and excess
H2O?
PCl5 + 4H2O → 5HCl + H3PO4
107. How many grams of Cl2 can be prepared from the reaction of 16.0 g of MnO2 and 30.0 g
of HCl according to the following chemical equation?
MnO2 + 4HCl → MnCl2 + Cl2 + 2H2O
Chapter 03 – Mass Relationships in Chemical Reactions
108. A sample of aluminum metal is placed in a graduated cylinder. It is noted that 5.50 mL
of water is displaced by the aluminum. The aluminum is then reacted with excess nitric acid
to produce aluminum nitrate and hydrogen gas. Given the density for aluminum is 2.702
g/mL, how many grams of aluminum nitrate are produced in the reaction?
2Al(s) + 6HNO3(aq) → 2Al(NO3)3(aq) + 3H2(g)
109. A sample of iron metal is placed in a graduated cylinder. It is noted that 10.4 mL of
water is displaced by the iron. The iron is then reacted with excess hydrochloric acid to
produce iron (II) chloride and hydrogen gas. Given the density for iron is 7.86 g/mL, how
many grams of iron (II) chloride are produced in the reaction?
Fe(s) + 2HCl(aq) → FeCl2(aq) + H2(g)
Chapter 03 – Mass Relationships in Chemical Reactions
110. Hydrogen chloride gas can be prepared by the following reaction:
2NaCl(s) + H2SO4(aq) → 2HCl(g) + Na2SO4(s)
How many grams of HCl can be prepared from 2.00 mol H2SO4 and 2.56 mol NaCl?
111. Calculate the mass of FeS formed when 9.42 g of iron reacts with 8.50 g of sulfur
according to the following reaction.
Fe(s) + S(s) → FeS(s)
Chapter 03 – Mass Relationships in Chemical Reactions
112. What is the theoretical yield of chromium that can be produced by the reaction of 40.0 g
of Cr2O3 with 8.00 g of aluminum according to the chemical equation below?
2Al + Cr2O3 → Al2O3 + 2Cr
113. Calculate the mass of excess reagent remaining at the end of the reaction in which 90.0 g
of SO2 are mixed with 100.0 g of O2.
2SO2 + O2 → 2SO3
Chapter 03 – Mass Relationships in Chemical Reactions
114. What is the theoretical yield of ammonia that can be obtained from the reaction of 10.0 g
of H2 and excess N2?
N2 + 3H2 → 2NH3
115. What is the theoretical yield of H2O that can be obtained from the reaction of 4.5 g H2
and excess O2?
2H2(g) + O2(g) → 2H2O(g)
Chapter 03 – Mass Relationships in Chemical Reactions
116. Ammonia reacts with oxygen to form nitric oxide and water vapor:
4NH3 + 5O2 → 4NO + 6H2O
What is the theoretical yield of water, in moles, when 40.0 g NH3 and 50.0 g O2 are mixed
and allowed to react?
117. What is the theoretical yield of vanadium, in moles, that can be produced by the reaction
of 2.0 moles of V2O5 with 6.0 moles of calcium based on the chemical reaction below?
V2O5(s) + 5Ca(l) → 2V(l) + 5CaO(s)
Chapter 03 – Mass Relationships in Chemical Reactions
118. What is the theoretical yield of vanadium, in moles, that can be produced by the reaction
of 1.0 mole of V2O5 with 4.0 moles of calcium based on the following chemical reaction?
V2O5(s) + 5Ca(l) → 2V(l) + 5CaO(s)
119. What is the theoretical yield of vanadium that can be produced by the reaction of 40.0 g
of V2O5 with 40.0 g of calcium based on the following chemical reaction?
V2O5(s) + 5Ca(l) → 2V(l) + 5CaO(s)
Chapter 03 – Mass Relationships in Chemical Reactions
120. The reaction of 44.1 g of Cr2O3 with 35.0 g of Al produced 25.6 g of Cr. What is the
percent yield for this reaction?
2Al + Cr2O3 → Al2O3 + 2Cr
121. The reaction of 60.0 g of aluminum oxide with 30.0 g of carbon produced 22.5 g of
aluminum. What is the percent yield for this reaction?
Al2O3 + 3C → 2Al + 3CO
Chapter 03 – Mass Relationships in Chemical Reactions
122. A 1.375 g sample of mannitol, a sugar found in seaweed, is burned completely in oxygen
to give 1.993 g of carbon dioxide and 0.9519 g of water. The empirical formula of mannitol
is
123. A 0.8715 g sample of sorbic acid, a compound first obtained from the berries of a certain
ash tree, is burned completely in oxygen to give 2.053 g of carbon dioxide and 0.5601 g of
water. The empirical formula of sorbic acid is
Chapter 03 – Mass Relationships in Chemical Reactions
124. Washing soda is a hydrate of sodium carbonate. Elemental analysis of a sample of
washing soda gave 4.20% C and 7.05% H. What is the formula for washing soda?
125. The first step in the Ostwald process for producing nitric acid is
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g).
If the reaction of 150. g of ammonia with 150. g of oxygen gas yields 87. g of nitric oxide
(NO), what is the percent yield of this reaction?
Chapter 03 – Mass Relationships in Chemical Reactions
126. One way of obtaining pure sodium carbonate is through the decomposition of the mineral
trona, Na 3(CO3)(HCO3)2H2O, as shown in the following reaction:
2Na3(CO3)(HCO3)2H2O(s) → 3Na2CO3(s) + CO2(g) + 5H2O(g)
When 15 metric tons (1 103 kg) of trona is decomposed, 11 metric tons of Na2CO3 is
recovered. What is the percent yield of this reaction? (1 metric ton = 103 kg)
127. When octane (C8H18) is burned in a particular internal combustion engine, the yield of
products (carbon dioxide and water) is 93%. What mass of carbon dioxide will be produced in
this engine when 15.0 g of octane is burned with 15.0 g of oxygen gas?
Chapter 03 – Mass Relationships in Chemical Reactions
128. The Hall process for the production of aluminum involves the reaction of aluminum
oxide with elemental carbon to give aluminum metal and carbon monoxide. If the yield of this
reaction is 75%, what mass of aluminum metal can be produced from the reaction of 1.65
106 g of aluminum oxide with 1.50 106 g of carbon?
129. The Hall process for the production of aluminum involves the reaction of aluminum
oxide with elemental carbon to give aluminum metal and carbon monoxide. If the percent
yield of this reaction is 82% and aluminum ore is 71% by mass aluminum oxide, what mass
of aluminum ore must be mined in order to produce 1.0 103 kg (1 metric ton) of aluminum
metal by the Hall process?
Chapter 03 – Mass Relationships in Chemical Reactions
130. A method for producing pure copper metal involves the reaction of copper(I) sulfide with
oxygen gas to give copper metal and sulfur dioxide. Suppose the yield of this reaction is 87%.
What mass of a copper ore consisting of 46% copper(I) sulfide must be mined in order to
produce 1.0 103 kg (1.0 metric ton) of copper metal?
131. Aluminum hydroxide reacts with nitric acid to form aluminum nitrate and water. What
mass of water can be formed by the reaction of 15.0 g of aluminum hydroxide with excess
nitric acid?