Question 1

Ozone (O3) in the atmosphere can be converted to oxygen gas by reaction with nitric oxide (NO) .(Nitrogen dioxide is also produced in the reaction.) What is the enthalpy change when 8.50 L of ozone at a pressure of 1.00 atm and 25°C reacts with 12.00 L of nitric oxide at the same initial pressure and temperature (R = 0.0821 L atm/mol K) ? [ΔH°f(NO) = 90.4 kJ/mol; ΔH°f(NO2) = 33.85 kJ/mol; ΔH°f(O3) = 142.2 kJ/mol]

Accepted Answer

A)  -69.1 kJ
B)  -19.7 kJ
C)  -1690 kJ
D)  -97.6 kJ
E)  -167 kJF) A) and C)
G) None of the above

Question 2

When heat is absorbed by the system and work is done by the system on the surroundings then

Accepted Answer

A)  q is negative and w is positive.
B)  both q and w are positive.
C)  both q and w are negative.
D)  q is positive and w is negative.
E)  both q and W are zero.F) C) and D)
G) A) and E)

Question 3

What is the change in internal energy in joules for a system that releases 154 J of heat and does 125 J of work on its surroundings?

Accepted Answer

A)  -29 J
B)  279 J
C)  29 J
D)  1.23 J
E)  -279 JF) A) and D)
G) D) and E)

Question 4

Suppose a sample of gas undergoes the following change of state.  Which statement(s) is/are true concerning this change of state? i.w must be positive.
Ii) w must be negative.
Iii) q must be positive.
Iv) q must be negative.

Accepted Answer

A)  I only
B)  II only
C)  II and III
D)  II and IV
E)  I and IIIF) B) and C)
G) B) and D)

Question 5

Which type of system may transfer energy,but not mass,to the surroundings?

Accepted Answer

A)  mass transfer system
B)  isolated system
C)  closed system
D)  nonenergy system
E)  open systemF) All of the above
G) A) and B)

Question 6

The sign of w when work is done by the system on the surroundings is _____________.

Accepted Answer

The answer of The sign of w when work is...

Question 7

For a particular process,28 kJ of heat is absorbed and 15 kJ of work is done on the surroundings.What is ΔU?

Accepted Answer

A)  ΔU = +43 kJ
B)  ΔU = -43 kJ
C)  ΔU = -13 kJ
D)  ΔU = +13 kJ
E)  ΔU = +28 kJF) A) and E)
G) A) and D)

Question 8

An ideal gas (the system) is contained in a flexible balloon at a pressure of 1 atm and is initially at a temperature of 20.°C.The surrounding air is at the same pressure,but its temperature is 25°C.When the system has equilibrated with its surroundings,both system and surroundings are at 25°C and 1 atm.In changing from the initial to the final state,which one of the following relationships regarding the system is correct?

Accepted Answer

A)  ΔU 
B)  ΔU = 0
C)  ΔH = 0
D)  W > 0
E)  q > 0F) D) and E)
G) None of the above

Question 9

A system delivers 222 J of heat to the surroundings while delivering 645 J of work.What is the change in the internal energy,ΔU,of the system?

Accepted Answer

A)  -423 J
B)  +423 J
C)  -867 J
D)  +867 J
E)  -222 JF) C) and D)
G) All of the above

Question 10

The standard temperature is _____; the standard concentration of a solution is _______; and the standard pressure is _____.

Accepted Answer

usually 25...

Question 11

How many calories are in 854.3 J? (1 cal = 4.184 J)

Accepted Answer

A)  4.897 × 10-3 cal
B)  204.2 cal
C)  1.171 ×10-3 cal
D)  0.2390 cal
E)  3574 calF) B) and E)
G) B) and D)

Question 12

What is ΔH°rxn for the following reaction? 2C8H18(l) + 17O2(g) → 16CO(g) + 18H2O(l) 
2C8H18(l) + 25O2(g) → 16CO2(g) + 18H2O(l) 
ΔH°rxn = -11020.kJ/mol
2CO(g) + O2(g) → 2CO2(g) 
ΔH°rxn = -566.0 kJ/mol

Accepted Answer

A)  -11020.kJ/mol
B)  +6492 kJ/mol
C)  -1964 kJ/mol
D)  -6492 kJ/mol
E)  -11586 kJ/molF) B) and E)
G) C) and E)

Question 13

To which one of the following reactions,occurring at 25oC,does the symbol ΔHof [H2SO4(l) ] refer?

Accepted Answer

A)  H2(g) + S(s) + 2O2(g)  H2SO4(l) 
B)  H2SO4(l)  H2(g) + S(s) + 2O2(g) 
C)  H2(g) + S(g) + 2O2(g)  H2SO4(l) 
D)  H2SO4(l)  2 H(g) + S(s) + 4O(g) 
E)  2H(g) +S(g) +4O(g)  H2SO4(l) F) A) and D)
G) A) and C)

Question 14

The statement,"Energy can neither be destroyed nor created," is the _____________.

Accepted Answer

first law ...

Exam 5: Thermochemistry

The statement,"Energy can neither be destroyed nor created," is the _____________.

Correct Answer
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first law ...
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The sign of w when work is done by the system on the surroundings is _____________.

Correct Answer
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What is ΔH°_rxn for the following reaction? 2C₈H₁₈(l) + 17O₂(g) → 16CO(g) + 18H₂O(l) 2C₈H₁₈(l) + 25O₂(g) → 16CO₂(g) + 18H₂O(l) ΔH°_rxn = -11020.kJ/mol 2CO(g) + O₂(g) → 2CO₂(g) ΔH°_rxn = -566.0 kJ/mol

Correct Answer
verified

What is the change in internal energy in joules for a system that releases 154 J of heat and does 125 J of work on its surroundings?

Correct Answer
verified

For a particular process,28 kJ of heat is absorbed and 15 kJ of work is done on the surroundings.What is ΔU?

Correct Answer
verified

The standard temperature is _; the standard concentration of a solution is _; and the standard pressure is ___.

Correct Answer
verified
usually 25...
View Answer

How many calories are in 854.3 J? (1 cal = 4.184 J)

Correct Answer
verified

When heat is absorbed by the system and work is done by the system on the surroundings then

Correct Answer
verified

To which one of the following reactions,occurring at 25^oC,does the symbol ΔH^o_f [H₂SO₄(l) ] refer?

Correct Answer
verified

Correct Answer
verified

Which type of system may transfer energy,but not mass,to the surroundings?

Correct Answer
verified

Correct Answer
verified

A system delivers 222 J of heat to the surroundings while delivering 645 J of work.What is the change in the internal energy,ΔU,of the system?

Correct Answer
verified

Suppose a sample of gas undergoes the following change of state. Which statement(s) is/are true concerning this change of state? i.w must be positive. Ii) w must be negative. Iii) q must be positive. Iv) q must be negative.

Correct Answer
verified

Exam 5: Thermochemistry

The statement,"Energy can neither be destroyed nor created," is the _____________.

Correct Answerverifiedfirst law ...View AnswerShow Answer

The sign of w when work is done by the system on the surroundings is _____________.

Correct AnswerverifiedShow Answer

What is ΔH°rxn for the following reaction? 2C8H18(l) + 17O2(g) → 16CO(g) + 18H2O(l) 2C8H18(l) + 25O2(g) → 16CO2(g) + 18H2O(l) ΔH°rxn = -11020.kJ/mol 2CO(g) + O2(g) → 2CO2(g) ΔH°rxn = -566.0 kJ/mol

Correct AnswerverifiedShow Answer

What is the change in internal energy in joules for a system that releases 154 J of heat and does 125 J of work on its surroundings?

Correct AnswerverifiedShow Answer

For a particular process,28 kJ of heat is absorbed and 15 kJ of work is done on the surroundings.What is ΔU?

Correct AnswerverifiedShow Answer

The standard temperature is _____; the standard concentration of a solution is _______; and the standard pressure is _____.

Correct Answerverifiedusually 25...View AnswerShow Answer

How many calories are in 854.3 J? (1 cal = 4.184 J)

Correct AnswerverifiedShow Answer

When heat is absorbed by the system and work is done by the system on the surroundings then

Correct AnswerverifiedShow Answer

To which one of the following reactions,occurring at 25oC,does the symbol ΔHof [H2SO4(l) ] refer?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which type of system may transfer energy,but not mass,to the surroundings?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A system delivers 222 J of heat to the surroundings while delivering 645 J of work.What is the change in the internal energy,ΔU,of the system?

Correct AnswerverifiedShow Answer

Suppose a sample of gas undergoes the following change of state. Which statement(s) is/are true concerning this change of state? i.w must be positive. Ii) w must be negative. Iii) q must be positive. Iv) q must be negative.

Correct AnswerverifiedShow Answer

Correct Answer
verified
first law ...
View Answer

Correct Answer
verified

What is ΔH°_rxn for the following reaction? 2C₈H₁₈(l) + 17O₂(g) → 16CO(g) + 18H₂O(l) 2C₈H₁₈(l) + 25O₂(g) → 16CO₂(g) + 18H₂O(l) ΔH°_rxn = -11020.kJ/mol 2CO(g) + O₂(g) → 2CO₂(g) ΔH°_rxn = -566.0 kJ/mol

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The standard temperature is _; the standard concentration of a solution is _; and the standard pressure is ___.

Correct Answer
verified
usually 25...
View Answer

Correct Answer
verified

Correct Answer
verified

To which one of the following reactions,occurring at 25^oC,does the symbol ΔH^o_f [H₂SO₄(l) ] refer?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified