Question 1

Consider the reaction between hydrogen and oxygen gases to form water: 2H2(g)  + O2(g)   →\rightarrow→   2H2O(l)  Which of the following is not conserved in this reaction?

Accepted Answer

A)  atoms
B)  moles of atoms
C)  moles of molecules
D)  mass E) B) and C)
F) A) and D)

Question 2

Which of the following equations is balanced?

Accepted Answer

A)  P4(s)  + 10O2(g)   →\rightarrow→  P4O10(s) 
B)  ZnS(s)  + 3O2(g)   →\rightarrow→ ZnO(s)  + 2SO2(g) 
C)  NH3(g)  + O2(g)   →\rightarrow→ NO2(g)  + H2O(g) 
D)  4KBrO3(s)   →\rightarrow→  3KBrO4(s)  + KBr(s) 
E)  2Na(s)  + P(s)  →\rightarrow→  Na3P(s)  F) B) and D)
G) All of the above

Question 3

When mixed, solutions of silver nitrate, AgNO3, and sodium phosphate, Na3PO4, will form a precipitate of silver phosphate, Ag3PO4.The balanced equation is 3AgNO3(aq)  + Na3PO4(aq)   →\rightarrow→  Ag3PO4(s)  + 3NaNO3(aq)  Which of the following statements regarding this reaction is incorrect?

Accepted Answer

A)  6 moles of AgNO3 will react with 2 moles of Na3PO4.
B)  9 moles of AgNO3 should react to form 2 moles of Ag3PO4, given sufficient Na3PO4.
C)  1.5 moles of NaNO3 should form when 0.5 mole of Na3PO4 reacts with sufficient AgNO3.
D)  3 moles of Ag3PO4 should form when 3 moles of Na3PO4 react with sufficient AgNO3.
E)  2 moles of Na3PO4 will react with 6 moles of AgNO3. F) A) and B)
G) A) and D)

Question 4

When ethanol, C2H5OH, a component in some gasoline mixtures, is burned in air, one molecule of ethanol combines with three oxygen molecules to form two CO2 molecules and three H2O molecules.Select the statement below that is incorrect in regard to this reaction.

Accepted Answer

A)  The balanced equation for the reaction is C2H5OH + 3O2  →\rightarrow→  2CO2 + 3H2O.
B)  If 4 ethanol molecules react, 8 CO2 molecules should form.
C)  If 12 H2O molecules are formed, then 9 O2 molecules must have reacted.
D)  If 15 ethanol molecules react, then 45 oxygen molecules must also react.
E)  If 12 CO2 molecules are formed, then 18 H2O molecules should also form. F) A) and B)
G) C) and E)

Question 5

When copper reacts with sulfur at high temperature, copper(I)  sulfide is formed. 2Cu(s)  + S(s)   →\rightarrow→  Cu2S(s)  If the mass of the Cu2S formed is 1.17 g, what mass of copper should have reacted?

Accepted Answer

A)  0.934 g
B)  not enough information
C)  0.78 g
D)  2.34 g
E)  0.467 g F) A) and E)
G) C) and E)

Question 6

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the following equation: ___P4(s)  + ___Cl2(g)  →\rightarrow→ ___PCl3(l)  (unbalanced)  Balance the equation and determine how many grams of chlorine would be required to react with 21.2 g of phosphorus.

Accepted Answer

A)  12.1 g
B)  48.6 g
C)  37.0 g
D)  148 g
E)  72.8 g F) B) and D)
G) A) and E)

Question 7

When magnesium is heated in air, it reacts with oxygen to form magnesium oxide: 2Mg(s)  + O2(g)   →\rightarrow→   2MgO(s)  If the mass of the magnesium solid increases by 0.335 g, what mass of magnesium metal should have reacted?

Accepted Answer

A)  0.882 g
B)  0.441 g
C)  0.509 g
D)  1.02 g
E)  not enough information F) C) and E)
G) C) and D)

Question 8

Consider the following reaction: Cr2O3(s)  + 3CCl4(l)   →\rightarrow→ 2CrCl3(s)  + 3COCl2(g)  green colorless purple colorless solid liquid solid gas When the green solid is mixed with the colorless liquid, the mixture starts to bubble and fume.When all action has stopped, a wet purple solid remains.Which substance is the limiting reactant?

Accepted Answer

A)  Cr2O3 
B)  CCl4 
C)  CrCl3 
D)  COCl2 
E)  there is no limiting reactant F) A) and B)
G) C) and D)

Question 9

When mixed, solutions of copper(II)  nitrate, Cu(NO3) 2, and sodium phosphate, Na3PO4, will form a precipitate of copper phosphate, Cu3(PO4) 2.The balanced equation is 3Cu(NO3) 2(aq)   + 2Na3PO4(aq)   →\rightarrow→  Cu3(PO4) 2(s)  + 6NaNO3(aq)  Which of the following statements regarding this reaction is incorrect?

Accepted Answer

A)  8 moles of Na3PO4 will react with 12 moles of Cu(NO3) 2.
B)  1 mole of NaNO3 should form when 0.5 mole of Cu(NO3) 2 reacts with sufficient Na3PO4.
C)  12 moles of Cu3(PO4) 2 should form when 36 moles of Cu(NO3) 2 reacts with sufficient Na3PO4.
D)  If 10 moles of Na3PO4 react with sufficient Cu(NO3) 2, 4 moles of Cu3(PO4) 2 should form.
E)  If 5 moles of Cu3(PO4) 2 are needed, it would require the combination of 15 moles of Cu(NO3) 2 and 10 moles of  Na3PO4. F) B) and C)
G) A) and E)

Question 10

A 3.50 g sample of rice was burned in a bomb calorimeter containing 1980 g of water.The temperature of the water increased from 22.75  °\degree° C to 28.88  °\degree° C.How much heat, in joules, did the rice sample release when it burned? [Cwater = 4.184 J/(g  °\degree° C) ]

Accepted Answer

A)  1.88 x 105 J
B)  2.39 x 105 J
C)  5.08 x 104 J
D)  3.33 x 102 J
E)  4.22 x 102 J F) A) and B)
G) C) and D)

Question 11

When one molecule of propane, C3H8, burns in a gas grill, it combines with five oxygen molecules to form three CO2 molecules and four H2O molecules.Select the statement below that is incorrect in regard to this reaction.

Accepted Answer

A)  The balanced equation for the reaction is C3H8 + 5O2  →\rightarrow→ 3CO2 + 4H2O.
B)  If 5 propane molecules react, 15 CO2 molecules should form.
C)  If 5 propane molecules react, 25 O2 molecules must also react.
D)  If 15 O2 molecules react, 9 H2O molecules should form.
E)  If 12 CO2 molecules are formed, then 4 propane molecules must have reacted. F) A) and B)
G) B) and E)

Question 12

Iron metal reacts with hydrochloric acid as follows: 2Fe(s)  + 6HCl(aq)   →\rightarrow→  2FeCl3(aq)  + 3H2(g)  If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl3 are collected, what is the percent yield of Al2(SO4) 3?

Accepted Answer

A)  65.0%
B)  109%
C)  91.4%
D)  73.0%
E)  not enough information given F) B) and E)
G) A) and B) C

Question 13

Small amounts of oxygen gas can be produced for laboratory use by heating potassium chlorate, which causes it to decompose by the following reaction: ___KClO3(s)   →\rightarrow→  ____KCl(s)  + ___O2(g)    (unbalanced)  Balance the equation, and determine the mass of oxygen that should be formed if 15.0 g of potassium chlorate decomposes.

Accepted Answer

A)  11.7 g
B)  57.5 g
C)  173 g
D)  5.88 g
E)  86.1 g F) B) and E)
G) B) and D) D

Question 14

Consider the reaction between acetylene, C2H2, and oxygen in a welding torch: 2C2H2(g)  + 5O2(g)   →\rightarrow→ 4CO2(g)  + 2H2O(g)  Which of the following is not conserved in this reaction?

Accepted Answer

A)  atoms
B)  moles of atoms
C)  moles of molecules
D)  mass E) A) and D)
F) A) and C)

Question 15

Given that 4NH3(g)  + 5O2(g)   →\rightarrow→  4NO(g)  + 6H2O(g) , if 4.5 moles of NH3 react with sufficient oxygen, how many moles of H2O should form?

Accepted Answer

A)  4.0
B)  4.5
C)  6.0
D)  6.8
E)  5.5 F) A) and C)
G) None of the above

Question 16

The limiting reactant in a chemical reaction is always the reactant which is present in the least amount in terms of mass.

Accepted Answer

A) True 
 B)False

Question 17

In a bomb calorimeter, the bomb itself, the water surrounding it, and the thermometer would be considered part of the "system."

Accepted Answer

A) True 
 B)False

Question 18

When 5.0 g CaCl2 is dissolved in water, how many moles of ions are in solution?

Accepted Answer

A)  0.135 mole
B)  0.045 mole
C)  5.0 moles
D)  15.0 moles
E)  1660 molesF) A) and E)
G) D) and E) A

Question 19

Consider the reaction N2(g)  + O2(g)   →\rightarrow→  2NO(g) .The molecular image represents a mixture of N2(g)  and O2(g)  just before reaction occurs.What is the limiting reactant, and how much of the excess reactant remains after the reaction is complete? The image contains 2 N2 molecules and 4 O2 molecules. 2(g)  + O2(g)   \rightarrow  2NO(g) .The molecular image represents a mixture of N2(g)  and O2(g)  just before reaction occurs.What is the limiting reactant, and how much of the excess reactant remains after the reaction is complete? The image contains 2 N2 molecules and 4 O2 molecules.   A) N2(g) , 1 O2(g)  B) N2(g) , 2 O2(g)  C) N2(g) , 3 O2(g)  D) O2(g) , 1 N2(g)  E) N2(g) , 0 O2(g)  " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  N2(g) , 1 O2(g) 
B)  N2(g) , 2 O2(g) 
C)  N2(g) , 3 O2(g) 
D)  O2(g) , 1 N2(g) 
E)  N2(g) , 0 O2(g)  F) D) and E)
G) A) and E)

Question 20

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: ___P4(s)  + ___Cl2(g)    →\rightarrow→  ___PCl3(l)  (unbalanced)  Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Accepted Answer

A)  6.07 g
B)  24.3 g
C)  36.4 g
D)  18.5 g
E)  74.1 g F) All of the above
G) C) and D)

Exam 6: Quantities in Chemical Reactions

Consider the reaction between hydrogen and oxygen gases to form water: 2H₂(g) + O₂(g) $\rightarrow$ 2H₂O(l) Which of the following is not conserved in this reaction?

Correct Answer
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Which of the following equations is balanced?

Correct Answer
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Correct Answer
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When ethanol, C₂H₅OH, a component in some gasoline mixtures, is burned in air, one molecule of ethanol combines with three oxygen molecules to form two CO₂ molecules and three H₂O molecules.Select the statement below that is incorrect in regard to this reaction.

Correct Answer
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When copper reacts with sulfur at high temperature, copper(I) sulfide is formed. 2Cu(s) + S(s) $\rightarrow$ Cu₂S(s) If the mass of the Cu₂S formed is 1.17 g, what mass of copper should have reacted?

Correct Answer
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When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the following equation: _P₄(s) + _Cl₂(g) $\rightarrow$ ___PCl₃(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 21.2 g of phosphorus.

Correct Answer
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When magnesium is heated in air, it reacts with oxygen to form magnesium oxide: 2Mg(s) + O₂(g) $\rightarrow$ 2MgO(s) If the mass of the magnesium solid increases by 0.335 g, what mass of magnesium metal should have reacted?

Correct Answer
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Correct Answer
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Correct Answer
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A 3.50 g sample of rice was burned in a bomb calorimeter containing 1980 g of water.The temperature of the water increased from 22.75 $\degree$ C to 28.88 $\degree$ C.How much heat, in joules, did the rice sample release when it burned? [C_water = 4.184 J/(g $\degree$ C) ]

Correct Answer
verified

When one molecule of propane, C₃H₈, burns in a gas grill, it combines with five oxygen molecules to form three CO₂ molecules and four H₂O molecules.Select the statement below that is incorrect in regard to this reaction.

Correct Answer
verified

Iron metal reacts with hydrochloric acid as follows: 2Fe(s) + 6HCl(aq) $\rightarrow$ 2FeCl₃(aq) + 3H₂(g) If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl₃ are collected, what is the percent yield of Al₂(SO₄) ₃?

Correct Answer
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C

Correct Answer
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D

Consider the reaction between acetylene, C₂H₂, and oxygen in a welding torch: 2C₂H₂(g) + 5O₂(g) $\rightarrow$ 4CO₂(g) + 2H₂O(g) Which of the following is not conserved in this reaction?

Correct Answer
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Given that 4NH₃(g) + 5O₂(g) $\rightarrow$ 4NO(g) + 6H₂O(g) , if 4.5 moles of NH₃react with sufficient oxygen, how many moles of H₂O should form?

Correct Answer
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The limiting reactant in a chemical reaction is always the reactant which is present in the least amount in terms of mass.

Correct Answer
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In a bomb calorimeter, the bomb itself, the water surrounding it, and the thermometer would be considered part of the "system."

Correct Answer
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When 5.0 g CaCl₂ is dissolved in water, how many moles of ions are in solution?

Correct Answer
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A

Correct Answer
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When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: _P₄(s) + _Cl₂(g) $\rightarrow$ ___PCl₃(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Correct Answer
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Exam 6: Quantities in Chemical Reactions

Consider the reaction between hydrogen and oxygen gases to form water: 2H2(g) + O2(g) →\rightarrow→ 2H2O(l) Which of the following is not conserved in this reaction?

Correct AnswerverifiedShow Answer

Which of the following equations is balanced?

Correct AnswerverifiedShow Answer

When mixed, solutions of silver nitrate, AgNO3, and sodium phosphate, Na3PO4, will form a precipitate of silver phosphate, Ag3PO4.The balanced equation is 3AgNO3(aq) + Na3PO4(aq) →\rightarrow→ Ag3PO4(s) + 3NaNO3(aq) Which of the following statements regarding this reaction is incorrect?

Correct AnswerverifiedShow Answer

When ethanol, C2H5OH, a component in some gasoline mixtures, is burned in air, one molecule of ethanol combines with three oxygen molecules to form two CO2 molecules and three H2O molecules.Select the statement below that is incorrect in regard to this reaction.

Correct AnswerverifiedShow Answer

When copper reacts with sulfur at high temperature, copper(I) sulfide is formed. 2Cu(s) + S(s) →\rightarrow→ Cu2S(s) If the mass of the Cu2S formed is 1.17 g, what mass of copper should have reacted?

Correct AnswerverifiedShow Answer

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the following equation: ___P4(s) + ___Cl2(g) →\rightarrow→ ___PCl3(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 21.2 g of phosphorus.

Correct AnswerverifiedShow Answer

When magnesium is heated in air, it reacts with oxygen to form magnesium oxide: 2Mg(s) + O2(g) →\rightarrow→ 2MgO(s) If the mass of the magnesium solid increases by 0.335 g, what mass of magnesium metal should have reacted?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A 3.50 g sample of rice was burned in a bomb calorimeter containing 1980 g of water.The temperature of the water increased from 22.75 °\degree° C to 28.88 °\degree° C.How much heat, in joules, did the rice sample release when it burned? [Cwater = 4.184 J/(g °\degree° C) ]

Correct AnswerverifiedShow Answer

When one molecule of propane, C3H8, burns in a gas grill, it combines with five oxygen molecules to form three CO2 molecules and four H2O molecules.Select the statement below that is incorrect in regard to this reaction.

Correct AnswerverifiedShow Answer

Iron metal reacts with hydrochloric acid as follows: 2Fe(s) + 6HCl(aq) →\rightarrow→ 2FeCl3(aq) + 3H2(g) If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl3 are collected, what is the percent yield of Al2(SO4) 3?

Correct AnswerverifiedC

Correct AnswerverifiedD

Consider the reaction between acetylene, C2H2, and oxygen in a welding torch: 2C2H2(g) + 5O2(g) →\rightarrow→ 4CO2(g) + 2H2O(g) Which of the following is not conserved in this reaction?

Correct AnswerverifiedShow Answer

Given that 4NH3(g) + 5O2(g) →\rightarrow→ 4NO(g) + 6H2O(g) , if 4.5 moles of NH3 react with sufficient oxygen, how many moles of H2O should form?

Correct AnswerverifiedShow Answer

The limiting reactant in a chemical reaction is always the reactant which is present in the least amount in terms of mass.

Correct AnswerverifiedShow Answer

In a bomb calorimeter, the bomb itself, the water surrounding it, and the thermometer would be considered part of the "system."

Correct AnswerverifiedShow Answer

When 5.0 g CaCl2 is dissolved in water, how many moles of ions are in solution?

Correct AnswerverifiedA

Correct AnswerverifiedShow Answer

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: ___P4(s) + ___Cl2(g) →\rightarrow→ ___PCl3(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Correct AnswerverifiedShow Answer

Consider the reaction between hydrogen and oxygen gases to form water: 2H₂(g) + O₂(g) $\rightarrow$ 2H₂O(l) Which of the following is not conserved in this reaction?

Correct Answer
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Correct Answer
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Correct Answer
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When ethanol, C₂H₅OH, a component in some gasoline mixtures, is burned in air, one molecule of ethanol combines with three oxygen molecules to form two CO₂ molecules and three H₂O molecules.Select the statement below that is incorrect in regard to this reaction.

Correct Answer
verified

When copper reacts with sulfur at high temperature, copper(I) sulfide is formed. 2Cu(s) + S(s) $\rightarrow$ Cu₂S(s) If the mass of the Cu₂S formed is 1.17 g, what mass of copper should have reacted?

Correct Answer
verified

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the following equation: _P₄(s) + _Cl₂(g) $\rightarrow$ ___PCl₃(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 21.2 g of phosphorus.

Correct Answer
verified

When magnesium is heated in air, it reacts with oxygen to form magnesium oxide: 2Mg(s) + O₂(g) $\rightarrow$ 2MgO(s) If the mass of the magnesium solid increases by 0.335 g, what mass of magnesium metal should have reacted?

Correct Answer
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Correct Answer
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Correct Answer
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A 3.50 g sample of rice was burned in a bomb calorimeter containing 1980 g of water.The temperature of the water increased from 22.75 $\degree$ C to 28.88 $\degree$ C.How much heat, in joules, did the rice sample release when it burned? [C_water = 4.184 J/(g $\degree$ C) ]

Correct Answer
verified

When one molecule of propane, C₃H₈, burns in a gas grill, it combines with five oxygen molecules to form three CO₂ molecules and four H₂O molecules.Select the statement below that is incorrect in regard to this reaction.

Correct Answer
verified

Iron metal reacts with hydrochloric acid as follows: 2Fe(s) + 6HCl(aq) $\rightarrow$ 2FeCl₃(aq) + 3H₂(g) If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl₃ are collected, what is the percent yield of Al₂(SO₄) ₃?

Correct Answer
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C

Correct Answer
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D

Consider the reaction between acetylene, C₂H₂, and oxygen in a welding torch: 2C₂H₂(g) + 5O₂(g) $\rightarrow$ 4CO₂(g) + 2H₂O(g) Which of the following is not conserved in this reaction?

Correct Answer
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Given that 4NH₃(g) + 5O₂(g) $\rightarrow$ 4NO(g) + 6H₂O(g) , if 4.5 moles of NH₃react with sufficient oxygen, how many moles of H₂O should form?

Correct Answer
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Correct Answer
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Correct Answer
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When 5.0 g CaCl₂ is dissolved in water, how many moles of ions are in solution?

Correct Answer
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A

Correct Answer
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When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: _P₄(s) + _Cl₂(g) $\rightarrow$ ___PCl₃(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Correct Answer
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