Question 1

The reactants,R + 2 S,are represented by

Accepted Answer

A) arrow B. 
B) line D. 
C) line E. 
D) line F. 
A) arrow B. 
B) line D. 
C) line E. 
D) line F.

Question 2

For an explosion in an open vessel,one would expect

Accepted Answer

A) ΔH to be positive and ΔE to be less than ΔH. 
B) ΔH to be positive and ΔE to be greater than ΔH. 
C) ΔH to be negative and ΔE to be less than ΔH. 
D) ΔH to be negative and ΔE to be greater than ΔH. 
A) ΔH to be positive and ΔE to be less than ΔH. 
B) ΔH to be positive and ΔE to be greater than ΔH. 
C) ΔH to be negative and ΔE to be less than ΔH. 
D) ΔH to be negative and ΔE to be greater than ΔH.

Question 3

When 50.0 mL of 0.400 M Ca(NO3)2 is added to 50.0 mL of 0.800 M NaF,CaF2 precipitates,as shown in the net ionic equation below.The initial temperature of both solutions is 25.00°C.Assuming that the reaction goes to completion,and that the resulting solution has a mass of 100.00 g and a specific heat of 4.18 J/(g ∙ °C),calculate the final temperature of the solution.
Ca2+(aq)+ 2 F-(aq)→ CaF2(s)ΔH° = -11.5 kJ

Accepted Answer

A) 24.45°C 
B) 25.55°C 
C) 26.10°C 
D) 26.65°C 
A) 24.45°C 
B) 25.55°C 
C) 26.10°C 
D) 26.65°C

Question 4

The SI unit for energy is the ________.

Accepted Answer

The answer of The SI unit for energy is the...

Question 5

Imagine a reaction that results in a change in both volume and temperature,as shown in the diagram below.What is the sign of the work being done and the sign of the enthalpy change involved in this reaction?

Accepted Answer

A) w = + and ΔH = + 
B) w = + and ΔH = - 
C) w = - and ΔH = + 
D) w = - and ΔH = - 
A) w = + and ΔH = + 
B) w = + and ΔH = - 
C) w = - and ΔH = + 
D) w = - and ΔH = -

Question 6

How much heat is transferred per mole of NH3(g)formed in the reaction shown below?
N2(g)+ 3 H2(g)→ 2 NH3(g)ΔH° = - 92.2 kJ

Accepted Answer

A) 92.2 kJ 
B) 46.1 kJ 
C) 30.7 kJ 
D) 15.4 kJ 
A) 92.2 kJ 
B) 46.1 kJ 
C) 30.7 kJ 
D) 15.4 kJ

Question 7

If a reaction with a negative value of ΔS is nonspontaneous at constant temperature and pressure,

Accepted Answer

A) ΔG is negative and ΔH may be positive or negative. 
B) ΔG is negative and ΔH is positive. 
C) ΔG is positive and ΔH may be positive or negative. 
D) ΔG is positive and ΔH is positive. 
A) ΔG is negative and ΔH may be positive or negative. 
B) ΔG is negative and ΔH is positive. 
C) ΔG is positive and ΔH may be positive or negative. 
D) ΔG is positive and ΔH is positive.

Question 8

A spontaneous reaction has a ________ value of ΔG and is favored by a ________ value of ΔH and a ________ value of ΔS.

Accepted Answer

negative,n

Question 9

Find ΔH° for the reaction C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(l).
ΔH° = -2046 kJ for the reaction: C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(g),and the heat of vaporization of water is 44.0 kJ/mol.Note that H2O is a liquid in the first reaction and a gas in the second.

Accepted Answer

A) -2222 kJ 
B) -2090 kJ 
C) -2002 kJ 
D) -1870 kJ 
A) -2222 kJ 
B) -2090 kJ 
C) -2002 kJ 
D) -1870 kJ

Question 10

The following drawing is a representation of the exothermic reaction in which ozone forms dioxygen.  
-This reaction is likely to be

Accepted Answer

A) nonspontaneous at all temperatures. 
B) nonspontaneous at low temperatures and spontaneous at high temperatures. 
C) spontaneous at low temperatures and nonspontaneous at high temperatures. 
D) spontaneous at all temperatures. 
A) nonspontaneous at all temperatures. 
B) nonspontaneous at low temperatures and spontaneous at high temperatures. 
C) spontaneous at low temperatures and nonspontaneous at high temperatures. 
D) spontaneous at all temperatures.

Question 11

At a given temperature and pressure,which of the following would be expected to have the greatest molar entropy?

Accepted Answer

A) Br2(s) 
B) Br2(l) 
C) Br2(g) 
D) All of these would be expected to have the same molar entropy. 
A) Br2(s) 
B) Br2(l) 
C) Br2(g) 
D) All of these would be expected to have the same molar entropy.

Question 12

Calculate the enthalpy of combustion per mole for C6H12O6.Assume that the combustion products are CO2(g)and H2O(l).

Accepted Answer

A) -5336 kJ/mol 
B) -2816 kJ/mol 
C) -1939 kJ/mol 
D) 580.7 kJ/mol 
A) -5336 kJ/mol 
B) -2816 kJ/mol 
C) -1939 kJ/mol 
D) 580.7 kJ/mol

Question 13

How much heat is absorbed when 30.00 g of C(s)reacts in the presence of excess SO2(g)to produce CS2(l)and CO(g)according to the following chemical equation?
5 C(s)+ 2 SO2(g)→ CS2(l)+ 4 CO(g)ΔH° = +239.9 kJ

Accepted Answer

A) 119.9 kJ 
B) 239.9 kJ 
C) 599.2 kJ 
D) 1439 kJ 
A) 119.9 kJ 
B) 239.9 kJ 
C) 599.2 kJ 
D) 1439 kJ

Question 14

When 1.50 g of Ba(s)is added to 100.00 g of water in a container open to the atmosphere,the reaction shown below occurs and the temperature of the resulting solution rises from 22.00°C to 33.10°C.If the specific heat of the solution is 4.18 J/(g ∙°C),calculate ΔH for the reaction,as written.
Ba(s)+ 2 H2O(l)→ Ba(OH)2(aq)+ H2(g)ΔH = ?

Accepted Answer

A) -431 kJ 
B) -3.14 kJ 
C) 3)14 kJ 
D) 431 kJ 
A) -431 kJ 
B) -3.14 kJ 
C) 3)14 kJ 
D) 431 kJ

Question 15

For the freezing of liquid bromine,Br2,at a given temperature and pressure,

Accepted Answer

A) ΔH is negative and ΔS is negative. 
B) ΔH is negative and ΔS is positive. 
C) ΔH is positive and ΔS is negative. 
D) ΔH is positive and ΔS is positive. 
A) ΔH is negative and ΔS is negative. 
B) ΔH is negative and ΔS is positive. 
C) ΔH is positive and ΔS is negative. 
D) ΔH is positive and ΔS is positive.

Question 16

In which case is the work done on the system always positive?

Accepted Answer

A) ΔE > 0 B) ΔV > 0 C) ΔV = 0 D) ΔV < 0 A) ΔE > 0 B) ΔV > 0 C) ΔV = 0 D) ΔV < 0

Question 17

One method for making ethanol,C2H5OH,involves the gas-phase hydration of ethylene,C2H4:
Estimate ΔH for this reaction from the given average bond dissociation energies,D.

Accepted Answer

A) -580 kJ 
B) -35 kJ 
C) +35 kJ 
D) 580 kJ 
A) -580 kJ 
B) -35 kJ 
C) +35 kJ 
D) 580 kJ

Question 18

For which reaction is H expected to be most positive?

Accepted Answer

A) N2(g)→ 2 N(g) 
B) O2(g)→ 2 O(g) 
C) 2 N(g)→ N2(g) 
D) 2 O(g)→ O2(g) 
A) N2(g)→ 2 N(g) 
B) O2(g)→ 2 O(g) 
C) 2 N(g)→ N2(g) 
D) 2 O(g)→ O2(g)

Question 19

Which is a measure of the sum of the kinetic and potential energies of each particle in the system?

Accepted Answer

A) E,the internal energy 
B) G,the Gibbs free energy 
C) H,the enthalpy 
D) T,the temperature 
A) E,the internal energy 
B) G,the Gibbs free energy 
C) H,the enthalpy 
D) T,the temperature

Question 20

When 10.00 moles of H2(g)reacts with 5.000 mol of O2(g)to form 10.00 mol of H2O(l)at 25°C and a constant pressure of 1.00 atm.If 683.0 kJ of heat are released during this reaction,and PΔV is equal to - 37.00 kJ,then

Accepted Answer

A) ΔH° = + 683.0 kJ and ΔE° = + 720.0 kJ. 
B) ΔH° = + 683.0 kJ and ΔE° = + 646.0 kJ. 
C) ΔH° = - 683.0 kJ and ΔE° = - 646.0 kJ. 
D) ΔH° = - 683.0 kJ and ΔE° = - 720.0 kJ. 
A) ΔH° = + 683.0 kJ and ΔE° = + 720.0 kJ. 
B) ΔH° = + 683.0 kJ and ΔE° = + 646.0 kJ. 
C) ΔH° = - 683.0 kJ and ΔE° = - 646.0 kJ. 
D) ΔH° = - 683.0 kJ and ΔE° = - 720.0 kJ.

Exam 8: Thermochemistry: Chemical Energy

The reactants,R + 2 S,are represented by

For an explosion in an open vessel,one would expect

The SI unit for energy is the ________.

Imagine a reaction that results in a change in both volume and temperature,as shown in the diagram below.What is the sign of the work being done and the sign of the enthalpy change involved in this reaction?

How much heat is transferred per mole of NH3(g)formed in the reaction shown below? N2(g)+ 3 H2(g)→ 2 NH3(g)ΔH° = - 92.2 kJ

If a reaction with a negative value of ΔS is nonspontaneous at constant temperature and pressure,

A spontaneous reaction has a ________ value of ΔG and is favored by a ________ value of ΔH and a ________ value of ΔS.

Find ΔH° for the reaction C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(l). ΔH° = -2046 kJ for the reaction: C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(g),and the heat of vaporization of water is 44.0 kJ/mol.Note that H2O is a liquid in the first reaction and a gas in the second.

The following drawing is a representation of the exothermic reaction in which ozone forms dioxygen. -This reaction is likely to be

At a given temperature and pressure,which of the following would be expected to have the greatest molar entropy?

Calculate the enthalpy of combustion per mole for C6H12O6.Assume that the combustion products are CO2(g)and H2O(l).

How much heat is absorbed when 30.00 g of C(s)reacts in the presence of excess SO2(g)to produce CS2(l)and CO(g)according to the following chemical equation? 5 C(s)+ 2 SO2(g)→ CS2(l)+ 4 CO(g)ΔH° = +239.9 kJ

For the freezing of liquid bromine,Br2,at a given temperature and pressure,

In which case is the work done on the system always positive?

One method for making ethanol,C2H5OH,involves the gas-phase hydration of ethylene,C2H4: Estimate ΔH for this reaction from the given average bond dissociation energies,D.

For which reaction is H expected to be most positive?

Which is a measure of the sum of the kinetic and potential energies of each particle in the system?

When 10.00 moles of H2(g)reacts with 5.000 mol of O2(g)to form 10.00 mol of H2O(l)at 25°C and a constant pressure of 1.00 atm.If 683.0 kJ of heat are released during this reaction,and PΔV is equal to - 37.00 kJ,then

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How much heat is transferred per mole of NH₃(g)formed in the reaction shown below? N₂(g)+ 3 H₂(g)→ 2 NH₃(g)ΔH° = - 92.2 kJ

A spontaneous reaction has a value of ΔG and is favored by a value of ΔH and a value of ΔS.

Find ΔH° for the reaction C₃H₈(g)+ 5 O₂(g)→ 3 CO₂(g)+ 4 H₂O(l). ΔH° = -2046 kJ for the reaction: C₃H₈(g)+ 5 O₂(g)→ 3 CO₂(g)+ 4 H₂O(g),and the heat of vaporization of water is 44.0 kJ/mol.Note that H₂O is a liquid in the first reaction and a gas in the second.

Calculate the enthalpy of combustion per mole for C₆H₁₂O₆.Assume that the combustion products are CO₂(g)and H₂O(l).

How much heat is absorbed when 30.00 g of C(s)reacts in the presence of excess SO₂(g)to produce CS₂(l)and CO(g)according to the following chemical equation? 5 C(s)+ 2 SO₂(g)→ CS₂(l)+ 4 CO(g)ΔH° = +239.9 kJ

For the freezing of liquid bromine,Br_2,at a given temperature and pressure,

One method for making ethanol,C₂H₅OH,involves the gas-phase hydration of ethylene,C₂H₄: Estimate ΔH for this reaction from the given average bond dissociation energies,D.

When 10.00 moles of H₂(g)reacts with 5.000 mol of O₂(g)to form 10.00 mol of H₂O(l)at 25°C and a constant pressure of 1.00 atm.If 683.0 kJ of heat are released during this reaction,and PΔV is equal to - 37.00 kJ,then