Question 1

Exhibit 5-1 Consider the reaction of Magnesium with oxygen to form magnesium oxide and heat as shown below to answer the following problem(s) :
2 Mg (s)  + O2 (g) →2 MgO (s)  D H ° rxn = - 1204 kJ
-Refer to Exhibit 5-1. How much heat is released when 2.43 grams of Mg (s)  reacts at constant pressure?
Molar Mass(Mg)  = 24.3 g/mol

Accepted Answer

A)   - 602 kJ
B)   - 240.8 kJ
C)   - 120.4 kJ
D)   - 60.2 kJ
E)   None of theseF) C) and D)
G) All of the above

Question 2

How much heat is required to raise the temperature of 25.0 grams of water from 32.0 ° C to 87.0 ° C?
Specific Heat (H2O)  = 4.184 J/g × ° C

Accepted Answer

A)   9.20 J
B)   329 J
C)   3.35×103 J
D)   5.75×103 J
E)   1.05×104 JF) A) and E)
G) C) and D)

Question 3

What is the specific heat of an unknown substance if 25.0 grams of the substance absorbs 77.0 calories of heat and the temperature increases by 5.5 ° C?

Accepted Answer

A)   0.51 cal/g × ° C
B)   0.513 cal/g × ° C
C)   0.56 cal/g × ° C
D)   0.616 cal/g × ° C
E)   0.62 cal/g × ° CF) D) and E)
G) C) and E) C

Question 4

Consider the following reaction and its corresponding enthalpy:
2 Mg (s)  + O2 (g) →2 MgO (s)  D H ° rxn = - 1204 kJ/mol What amount of heat is exchanged when 5.00 grams of magnesium metal reacts at constant pressure?

Accepted Answer

A)   - 124 kJ
B)   - 248 kJ
C)   - 3.01×103 kJ
D)   7.32×104 kJ
E)   1.44×105 kJF) A) and B)
G) A) and C)

Question 5

The heat exchange of a certain exothermic reaction is measured in a solution calorimeter. The sign convention for the heat exchanged in this process would be a ____ value for the heat released in the reaction and a ____ value for the heat absorbed by the calorimeter.

Accepted Answer

A)   negative ( - ) , positive (+) 
B)   positive (+) , negative ( - ) 
C)   negative ( - ) , negative ( - ) 
D)   positive (+) , positive (+) E) B) and D)
F) B) and C)

Question 6

How many joules of heat are necessary to raise the temperature of a 1.42 kg block of copper from 25.0 ° C to 88.5 ° C?
(Specific heat of copper = 0.385 J/g × ° C)

Accepted Answer

A)   234000 J
B)   34700 J
C)   234 J
D)   34.7 J
E)   0.0347 JF) A) and E)
G) All of the above

Question 7

Given the following Thermodynamic data:
D H f (Fe2 O3 ; s)  = - 822 kJ/mol D H f (FeCl 3 ; s)  = - 400 kJ/mol D H f (H₂ O; g)  = - 242 kJ/mol D H f (H₂ O; 2 O3 ; s)  = - 822 kJ/mol D H f (FeCl 3 ; s)  = - 400 kJ/mol D H f (H₂ O; g)  = - 242 kJ/mol D H f (H₂ O;   )  = - 286 kJ/mol D H f (HCl; g)  = - 92 kJ/mol D H f (HCl; aq)  = - 167 kJ/mol What is the Standard Molar Enthalpy of Reaction D H rxn for the following reaction? Fe2 O3(s)  + 6 HCl (g)  2 FeCl 3 (s)  + 3 H₂ O (g)  D H rxn = ?? A)  - 1256 kJ/mol B)  - 284 kJ/mol C)  - 152 kJ/mol D)  272 kJ/mol E)  298 kJ/mol" class="answers-bank-image d-inline" rel="preload" > )  = - 286 kJ/mol D H f (HCl; g)  = - 92 kJ/mol D H f (HCl; aq)  = - 167 kJ/mol What is the Standard Molar Enthalpy of Reaction D H rxn for the following reaction?
Fe2 O3(s)  + 6 HCl (g)  2 FeCl 3 (s)  + 3 H₂ O (g)  D H rxn = ??

Accepted Answer

A)   - 1256 kJ/mol
B)   - 284 kJ/mol
C)   - 152 kJ/mol
D)   272 kJ/mol
E)   298 kJ/molF) A) and B)
G) B) and E)

Question 8

When a 83.0 g sample of a metal at 100.0 ° C is added tO45.0 g of water at 23.25 ° C, the final temperature of both the water and metal is 27.68 ° C. The specific heat of water is 4.184 J/g × K. What is the specific heat of the metal?

Accepted Answer

A)   10.0 J/g × K
B)   11.5 J/g × K
C)   0.100 J/g × K
D)   0.139 J/g × K
E)   none of theseF) A) and B)
G) A) and C)

Question 9

Given the data below, what is D H ° for the following reaction?
CH4 (g)  + 3 Cl2 (g) →CHCl3 (g)  + 3 HCl (g)  D H ° f [CH4 (g) ] = - 75 kJ/mol D H ° f [CHCl3 (g) ] = - 103 kJ/mol D H ° f [HCl (g) ] = - 92 kJ/mol

Accepted Answer

A)   - 304 kJ
B)   - 120 kJ
C)   +304 kJ
D)   +120 kJ
E)   none of theseF) A) and B)
G) C) and D)

Question 10

Which of the following reactions absorbs heat from the surroundings in order to proceed to completion?
I. CO (g)  + 1/2 O2 (g) →CO2 (g)  D H rxn = - 283.0 kJ
II. Al2O3 (s) →2 Al (s)  + 3/2 O2 (g)  (endothermic) 
III. SO3 (g)  + 99.2 kJ→S (s)  + 3/2 O2 (g)

Accepted Answer

A)   I only
B)   I and III
C)   I and II
D)   II and III
E)   All of theseF) A) and B)
G) A) and C)

Question 11

When a 50.0 g sample of a metal at 100.0 ° C is added tO60.0 g of water at 25.10 ° C, the final temperature of both the water and metal is 32.81 ° C. The specific heat of water is 4.184 J/g × K. What is the specific heat of the metal?

Accepted Answer

A)   0.576 J/g × K
B)   1.66 J/g × K
C)   45.0 J/g × K
D)   0.900 J/g × K
E)   none of theseF) A) and E)
G) A) and D) A

Question 12

The reaction of 8.00 g of SO2 (g)  burns in excess oxygen. 9.85 kJ of heat are released. What is D H for the following thermochemical equation?
2 SO2 (g)  + O2 (g) →2 SO3 (g)

Accepted Answer

A)   - 1.58×102 kJ
B)   - 78.8 kJ
C)   - 39.4 kJ
D)   +78.8 kJ
E)   none of theseF) A) and D)
G) D) and E)

Question 13

When a 2.00 g sample of ammonium nitrate (NH4NO3)  dissolves in 48.0 g of water the temperature changes from 26.57 ° C to 23.50 ° C. Assuming the specific heat of the solution is 4.184 J/g × K, what is the enthalpy change for dissolving 2.00 g of ammonium nitrate in water?

Accepted Answer

A)   +616 J
B)   +642 J
C)   - 642 J
D)   - 616 J
E)   none of theseF) A) and E)
G) A) and B)

Question 14

Which of the following substances is expected to have a standard molar enthalpy of formation D H ° f equal to zero?

Accepted Answer

A)   NaCl (s) 
B)   H2 (g) 
C)   HCl (aq) 
D)   N₂( f equal to zero? 
A)   NaCl (s)  
B)   H2 (g)  
C)   HCl (aq)  
D)   N₂(   )  
E)   CO2 (s) " class="answers-bank-image d-inline" rel="preload" > ) 
E)   CO2 (s) F) A) and E)
G) B) and D)

Question 15

How much heat must be removed from a 10.0 g sample of graphite (specific heat = 0.720 J/g × K)  to decrease its temperature from 55.00 ° C tO44.00 ° C?

Accepted Answer

A)   0.720 J
B)   7.20 J
C)   7.92 J
D)   79.2 J
E)   none of theseF) B) and C)
G) A) and C)

Question 16

What is the final temperature upon mixing 75.0 grams of water held at 45.0 ° C witH₂ 5.0 grams of water held at 90.0 ° C?

Accepted Answer

A)   11.3 ° C
B)   28.1 ° C
C)   56.3 ° C
D)   67.5 ° C
E)   78.8 ° CF) A) and E)
G) C) and D)

Question 17

A reaction of 3.44 g of H2 (g)  and 20.5 g of C (s)  yields C3H6 (g) , and the enthalphy change is - 11.6 kJ. What is D H for the following reaction?
3 H2 (g)  + 3 C (s) →C3H6 (g)

Accepted Answer

A)   - 20.4 kJ
B)   - 11.6 kJ
C)   - 31.7 kJ
D)   - 61.2 kJ
E)   none of theseF) A) and E)
G) A) and D)

Question 18

Which unit from those listed below would be the best choice as a unit for the heat capacity of a substance?

Accepted Answer

A)   J
B)   J/mol
C)   J/g
D)   J/ ° C
E)   J/g × ° CF) A) and E)
G) A) and B) D

Question 19

Which of the following defines the heat of formation of Fe2O3 (s) ?

Accepted Answer

A)   2 Fe (g)  + 3 O (g) → Fe2O3 (s) 
B)   2 Fe (s)  + 3/2 O2 (g) → Fe2O3 (s) 
C)   4 Fe (s)  + 2 O3 (g) → 2 Fe2O3 (s) 
D)   2 Fe (g)  + 3 O (g) → Fe2O3 (g) 
E)   none of theseF) B) and C)
G) B) and E)

Question 20

Given the equation below, what is D H for the reaction that converts 6.00 g of H₂ O (  )  into H₂ O₂ (  )  and H₂ (g) ?
2 H₂ O (  )  H₂ O₂ (  )  + H₂ (g)  D H = 384 kJ

Accepted Answer

A)   129 kJ
B)   64.0 kJ
C)   256 kJ
D)   384 kJ
E)   none of theseF) C) and D)
G) None of the above

Exam 5: Thermochemistry

Correct Answer
verified

How much heat is required to raise the temperature of 25.0 grams of water from 32.0 ° C to 87.0 ° C? Specific Heat (H₂O) = 4.184 J/g × ° C

Correct Answer
verified

What is the specific heat of an unknown substance if 25.0 grams of the substance absorbs 77.0 calories of heat and the temperature increases by 5.5 ° C?

Correct Answer
verified
C

Consider the following reaction and its corresponding enthalpy: 2 Mg (s) + O₂ (g) →2 MgO (s) D H ° _rxn= - 1204 kJ/mol What amount of heat is exchanged when 5.00 grams of magnesium metal reacts at constant pressure?

Correct Answer
verified

The heat exchange of a certain exothermic reaction is measured in a solution calorimeter. The sign convention for the heat exchanged in this process would be a value for the heat released in the reaction and a value for the heat absorbed by the calorimeter.

Correct Answer
verified

How many joules of heat are necessary to raise the temperature of a 1.42 kg block of copper from 25.0 ° C to 88.5 ° C? (Specific heat of copper = 0.385 J/g × ° C)

Correct Answer
verified

Correct Answer
verified

When a 83.0 g sample of a metal at 100.0 ° C is added tO₄5.0 g of water at 23.25 ° C, the final temperature of both the water and metal is 27.68 ° C. The specific heat of water is 4.184 J/g × K. What is the specific heat of the metal?

Correct Answer
verified

Given the data below, what is D H ° for the following reaction? CH₄ (g) + 3 Cl₂ (g) →CHCl₃ (g) + 3 HCl (g) D H ° _f [CH₄ (g) ] = - 75 kJ/mol D H ° _f [CHCl₃ (g) ] = - 103 kJ/mol D H ° _f [HCl (g) ] = - 92 kJ/mol

Correct Answer
verified

Which of the following reactions absorbs heat from the surroundings in order to proceed to completion? I. CO (g) + ¹/₂ O₂ (g) →CO₂ (g) D H _rxn = - 283.0 kJ II. Al₂O₃ (s) →2 Al (s) + ³/₂ O₂ (g) (endothermic) III. SO₃ (g) + 99.2 kJ→S (s) + ³/₂ O₂ (g)

Correct Answer
verified

When a 50.0 g sample of a metal at 100.0 ° C is added tO₆0.0 g of water at 25.10 ° C, the final temperature of both the water and metal is 32.81 ° C. The specific heat of water is 4.184 J/g × K. What is the specific heat of the metal?

Correct Answer
verified
A

The reaction of 8.00 g of SO₂ (g) burns in excess oxygen. 9.85 kJ of heat are released. What is D H for the following thermochemical equation? 2 SO₂ (g) + O₂ (g) →2 SO₃ (g)

Correct Answer
verified

When a 2.00 g sample of ammonium nitrate (NH₄NO₃) dissolves in 48.0 g of water the temperature changes from 26.57 ° C to 23.50 ° C. Assuming the specific heat of the solution is 4.184 J/g × K, what is the enthalpy change for dissolving 2.00 g of ammonium nitrate in water?

Correct Answer
verified

Which of the following substances is expected to have a standard molar enthalpy of formation D H ° _f equal to zero?

Correct Answer
verified

How much heat must be removed from a 10.0 g sample of graphite (specific heat = 0.720 J/g × K) to decrease its temperature from 55.00 ° C tO₄4.00 ° C?

Correct Answer
verified

What is the final temperature upon mixing 75.0 grams of water held at 45.0 ° C witH₂ 5.0 grams of water held at 90.0 ° C?

Correct Answer
verified

A reaction of 3.44 g of H₂ (g) and 20.5 g of C (s) yields C₃H₆ (g) , and the enthalphy change is - 11.6 kJ. What is D H for the following reaction? 3 H₂ (g) + 3 C (s) →C₃H₆ (g)

Correct Answer
verified

Which unit from those listed below would be the best choice as a unit for the heat capacity of a substance?

Correct Answer
verified
D

Which of the following defines the heat of formation of Fe₂O₃ (s) ?

Correct Answer
verified

Given the equation below, what is D H for the reaction that converts 6.00 g of H₂ O ( ) into H₂ O₂ ( ) and H₂ (g) ? 2 H₂ O ( ) H₂ O₂ ( ) + H₂ (g) D H = 384 kJ

Correct Answer
verified

Exam 5: Thermochemistry

Correct AnswerverifiedShow Answer

How much heat is required to raise the temperature of 25.0 grams of water from 32.0 ° C to 87.0 ° C? Specific Heat (H2O) = 4.184 J/g × ° C

Correct AnswerverifiedShow Answer

What is the specific heat of an unknown substance if 25.0 grams of the substance absorbs 77.0 calories of heat and the temperature increases by 5.5 ° C?

Correct AnswerverifiedC

Consider the following reaction and its corresponding enthalpy: 2 Mg (s) + O2 (g) →2 MgO (s) D H ° rxn = - 1204 kJ/mol What amount of heat is exchanged when 5.00 grams of magnesium metal reacts at constant pressure?

Correct AnswerverifiedShow Answer

The heat exchange of a certain exothermic reaction is measured in a solution calorimeter. The sign convention for the heat exchanged in this process would be a ____ value for the heat released in the reaction and a ____ value for the heat absorbed by the calorimeter.

Correct AnswerverifiedShow Answer

How many joules of heat are necessary to raise the temperature of a 1.42 kg block of copper from 25.0 ° C to 88.5 ° C? (Specific heat of copper = 0.385 J/g × ° C)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

When a 83.0 g sample of a metal at 100.0 ° C is added tO45.0 g of water at 23.25 ° C, the final temperature of both the water and metal is 27.68 ° C. The specific heat of water is 4.184 J/g × K. What is the specific heat of the metal?

Correct AnswerverifiedShow Answer

Given the data below, what is D H ° for the following reaction? CH4 (g) + 3 Cl2 (g) →CHCl3 (g) + 3 HCl (g) D H ° f [CH4 (g) ] = - 75 kJ/mol D H ° f [CHCl3 (g) ] = - 103 kJ/mol D H ° f [HCl (g) ] = - 92 kJ/mol

Correct AnswerverifiedShow Answer

Which of the following reactions absorbs heat from the surroundings in order to proceed to completion? I. CO (g) + 1/2 O2 (g) →CO2 (g) D H rxn = - 283.0 kJ II. Al2O3 (s) →2 Al (s) + 3/2 O2 (g) (endothermic) III. SO3 (g) + 99.2 kJ→S (s) + 3/2 O2 (g)

Correct AnswerverifiedShow Answer

When a 50.0 g sample of a metal at 100.0 ° C is added tO60.0 g of water at 25.10 ° C, the final temperature of both the water and metal is 32.81 ° C. The specific heat of water is 4.184 J/g × K. What is the specific heat of the metal?

Correct AnswerverifiedA

The reaction of 8.00 g of SO2 (g) burns in excess oxygen. 9.85 kJ of heat are released. What is D H for the following thermochemical equation? 2 SO2 (g) + O2 (g) →2 SO3 (g)

Correct AnswerverifiedShow Answer

When a 2.00 g sample of ammonium nitrate (NH4NO3) dissolves in 48.0 g of water the temperature changes from 26.57 ° C to 23.50 ° C. Assuming the specific heat of the solution is 4.184 J/g × K, what is the enthalpy change for dissolving 2.00 g of ammonium nitrate in water?

Correct AnswerverifiedShow Answer

Which of the following substances is expected to have a standard molar enthalpy of formation D H ° f equal to zero?

Correct AnswerverifiedShow Answer

How much heat must be removed from a 10.0 g sample of graphite (specific heat = 0.720 J/g × K) to decrease its temperature from 55.00 ° C tO44.00 ° C?

Correct AnswerverifiedShow Answer

What is the final temperature upon mixing 75.0 grams of water held at 45.0 ° C witH₂ 5.0 grams of water held at 90.0 ° C?

Correct AnswerverifiedShow Answer

A reaction of 3.44 g of H2 (g) and 20.5 g of C (s) yields C3H6 (g) , and the enthalphy change is - 11.6 kJ. What is D H for the following reaction? 3 H2 (g) + 3 C (s) →C3H6 (g)

Correct AnswerverifiedShow Answer

Which unit from those listed below would be the best choice as a unit for the heat capacity of a substance?

Correct AnswerverifiedD

Which of the following defines the heat of formation of Fe2O3 (s) ?

Correct AnswerverifiedShow Answer

Given the equation below, what is D H for the reaction that converts 6.00 g of H₂ O ( ) into H₂ O₂ ( ) and H₂ (g) ? 2 H₂ O ( ) H₂ O₂ ( ) + H₂ (g) D H = 384 kJ

Correct AnswerverifiedShow Answer

Correct Answer
verified

How much heat is required to raise the temperature of 25.0 grams of water from 32.0 ° C to 87.0 ° C? Specific Heat (H₂O) = 4.184 J/g × ° C

Correct Answer
verified

Correct Answer
verified
C

Consider the following reaction and its corresponding enthalpy: 2 Mg (s) + O₂ (g) →2 MgO (s) D H ° _rxn= - 1204 kJ/mol What amount of heat is exchanged when 5.00 grams of magnesium metal reacts at constant pressure?

Correct Answer
verified

The heat exchange of a certain exothermic reaction is measured in a solution calorimeter. The sign convention for the heat exchanged in this process would be a value for the heat released in the reaction and a value for the heat absorbed by the calorimeter.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

When a 83.0 g sample of a metal at 100.0 ° C is added tO₄5.0 g of water at 23.25 ° C, the final temperature of both the water and metal is 27.68 ° C. The specific heat of water is 4.184 J/g × K. What is the specific heat of the metal?

Correct Answer
verified

Given the data below, what is D H ° for the following reaction? CH₄ (g) + 3 Cl₂ (g) →CHCl₃ (g) + 3 HCl (g) D H ° _f [CH₄ (g) ] = - 75 kJ/mol D H ° _f [CHCl₃ (g) ] = - 103 kJ/mol D H ° _f [HCl (g) ] = - 92 kJ/mol

Correct Answer
verified

Which of the following reactions absorbs heat from the surroundings in order to proceed to completion? I. CO (g) + ¹/₂ O₂ (g) →CO₂ (g) D H _rxn = - 283.0 kJ II. Al₂O₃ (s) →2 Al (s) + ³/₂ O₂ (g) (endothermic) III. SO₃ (g) + 99.2 kJ→S (s) + ³/₂ O₂ (g)

Correct Answer
verified

When a 50.0 g sample of a metal at 100.0 ° C is added tO₆0.0 g of water at 25.10 ° C, the final temperature of both the water and metal is 32.81 ° C. The specific heat of water is 4.184 J/g × K. What is the specific heat of the metal?

Correct Answer
verified
A

The reaction of 8.00 g of SO₂ (g) burns in excess oxygen. 9.85 kJ of heat are released. What is D H for the following thermochemical equation? 2 SO₂ (g) + O₂ (g) →2 SO₃ (g)

Correct Answer
verified

When a 2.00 g sample of ammonium nitrate (NH₄NO₃) dissolves in 48.0 g of water the temperature changes from 26.57 ° C to 23.50 ° C. Assuming the specific heat of the solution is 4.184 J/g × K, what is the enthalpy change for dissolving 2.00 g of ammonium nitrate in water?

Correct Answer
verified

Which of the following substances is expected to have a standard molar enthalpy of formation D H ° _f equal to zero?

Correct Answer
verified

How much heat must be removed from a 10.0 g sample of graphite (specific heat = 0.720 J/g × K) to decrease its temperature from 55.00 ° C tO₄4.00 ° C?

Correct Answer
verified

Correct Answer
verified

A reaction of 3.44 g of H₂ (g) and 20.5 g of C (s) yields C₃H₆ (g) , and the enthalphy change is - 11.6 kJ. What is D H for the following reaction? 3 H₂ (g) + 3 C (s) →C₃H₆ (g)

Correct Answer
verified

Correct Answer
verified
D

Which of the following defines the heat of formation of Fe₂O₃ (s) ?

Correct Answer
verified

Correct Answer
verified