Question 1

What are the signs of ΔH,ΔS,and ΔG for the following spontaneous change?

Accepted Answer

A) ΔH = +,ΔS = +,ΔG = - 
B) ΔH = +,ΔS = -,ΔG = - 
C) ΔH = -,ΔS = +,ΔG = - 
D) ΔH = -,ΔS = -,ΔG = - 
A) ΔH = +,ΔS = +,ΔG = - 
B) ΔH = +,ΔS = -,ΔG = - 
C) ΔH = -,ΔS = +,ΔG = - 
D) ΔH = -,ΔS = -,ΔG = -

Question 2

The following drawing is a representation of a reaction of the type A → B,where different shaded spheres represent different molecular structures.For this reaction ΔH° = -30 kJ.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 3

A process is carried out at constant pressure.Given that ΔE is positive and ΔH is negative,

Accepted Answer

A) the system absorbs heat and expands during the process. 
B) the system absorbs heat and contracts during the process. 
C) the system loses heat and expands during the process. 
D) the system loses heat and contracts during the process. 
A) the system absorbs heat and expands during the process. 
B) the system absorbs heat and contracts during the process. 
C) the system loses heat and expands during the process. 
D) the system loses heat and contracts during the process.

Question 4

An ideal gas expands into a vacuum (external pressure = 0)without gaining or losing heat.For this expansion

Accepted Answer

A) ΔE increases. 
B) ΔE does not change. 
C) ΔE decreases. 
D) ΔE = TΔS 
A) ΔE increases. 
B) ΔE does not change. 
C) ΔE decreases. 
D) ΔE = TΔS

Question 5

How much heat is absorbed/released when 35.00 g of NH3(g)reacts in the presence of excess O2(g)to produce NO(g)and H2O(l)according to the following chemical equation?
4 NH3(g)+ 5 O2(g)→ 4 NO(g)+ 6 H2O(l)ΔH° = 1168 kJ

Accepted Answer

A) 600.1 kJ of heat are absorbed. 
B) 600.1 kJ of heat are released. 
C) 2400 kJ of heat are absorbed. 
D) 2400 kJ of heat are released. 
A) 600.1 kJ of heat are absorbed. 
B) 600.1 kJ of heat are released. 
C) 2400 kJ of heat are absorbed. 
D) 2400 kJ of heat are released.

Question 6

A slice of cheese pizza has a caloric content of 150 Cal.If this energy could be used to power a 2500 Watt microwave oven,how many minutes could the microwave oven be operated?

Accepted Answer

A) 1)0 min 
B) 4)2 min 
C) 11 min 
D) 15 min 
A) 1)0 min 
B) 4)2 min 
C) 11 min 
D) 15 min

Question 7

The law of conservation of energy is also known as the ________ law of thermodynamics.

Accepted Answer

The answer of The law of conservation of energy is...

Question 8

Calculate the work,w,gained or lost by the system when a gas expands from 15 L to 40 L against a constant external pressure of 1.5 atm.1 L ∙ atm = 101 J

Accepted Answer

A) - 6.1 kJ 
B) - 3.8 kJ 
C) + 3.8 kJ 
D) + 6.1 kJ 
A) - 6.1 kJ 
B) - 3.8 kJ 
C) + 3.8 kJ 
D) + 6.1 kJ

Question 9

The following drawing is a representation of a reaction for which ΔH° = -22 kJ.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 10

A reaction that absorbs 49.6 kJ from the surroundings in a vessel that undergoes a volume decrease of 1.25 L at a constant 4.00 atm pressure has an energy change,ΔE = ________ kJ.

Accepted Answer

The answer of A reaction that absorbs 49.6 kJ from...

Question 11

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 23.0°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) 22.45°C 
B) 23.55°C 
C) 24.10°C 
D) 24.65°C 
A) 22.45°C 
B) 23.55°C 
C) 24.10°C 
D) 24.65°C

Question 12

At constant pressure,the combustion of 15.0 g of C2H6(g)releases 777 kJ of heat.What is ΔH for the reaction given below?
2 C2H6(g)+ 7 O2(g)→ 4 CO2(g)+ 6 H2O(l)

Accepted Answer

A) - 129 kJ 
B) - 779 kJ 
C) -1560 kJ 
D) -3120 kJ 
A) - 129 kJ 
B) - 779 kJ 
C) -1560 kJ 
D) -3120 kJ

Question 13

For which should the standard heat of formation ΔH°f,be zero at 25°C?

Accepted Answer

A) O(g) 
B) O2(g) 
C) O3(g) 
D) all the above 
A) O(g) 
B) O2(g) 
C) O3(g) 
D) all the above

Question 14

Which of the following is not true?

Accepted Answer

A) A spontaneous reaction need not occur immediately. 
B) A spontaneous reaction must be exothermic and must have an increase in entropy. 
C) The reverse of a nonspontaneous reaction is always spontaneous. 
D) A spontaneous reaction is one that can proceed on its own. 
A) A spontaneous reaction need not occur immediately. 
B) A spontaneous reaction must be exothermic and must have an increase in entropy. 
C) The reverse of a nonspontaneous reaction is always spontaneous. 
D) A spontaneous reaction is one that can proceed on its own.

Question 15

The sum of the potential and kinetic energies for every molecule or ion in a system is the ________ energy of the system and is given the symbol ________.

Accepted Answer

The answer of The sum of the potential and kinetic...

Question 16

Given: S (s)+ O2 (g)→ SO2 (g)ΔH° = -296.1 kJ
2 SO3 (g)→ 2 SO2 (g)+ O2 (g)ΔH° = 198.2 kJ
Find ΔH° for : 2 S(s)+ 3 O2(g)→ 2 SO3(g)

Accepted Answer

A) -790.4 kJ 
B) -394.0 kJ 
C) -97.9 kJ 
D) +97.9 kJ 
A) -790.4 kJ 
B) -394.0 kJ 
C) -97.9 kJ 
D) +97.9 kJ

Question 17

In the reaction shown below,________ kJ of heat are released per mole of O2(g)that reacts.
C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(g)ΔH = -2045 kJ

Accepted Answer

Question 18

10.0 g of a metal,initially at 25°C,are placed into 10.0 g of water,initially at 100°C.Which metal will have the highest final temperature? Shown after each metal is its specific heat in J/(g∙°C).

Accepted Answer

A) aluminum (0.902) 
B) copper (0.385) 
C) Gold (0.129) 
D) iron (0.450) 
A) aluminum (0.902) 
B) copper (0.385) 
C) Gold (0.129) 
D) iron (0.450)

Question 19

Which depends only on the initial and final state?

Accepted Answer

A) q 
B) w 
C) q + w 
D) q - w 
A) q 
B) w 
C) q + w 
D) q - w

Question 20

Given: 4 NO2(g)+ O2(g)→ 2 N2O5(g)ΔH° = -110.2 kJ
Find ΔH° for N2O5(g)→ 2 NO2(g)+ 1/2 O2(g).

Accepted Answer

A) -220.4 kJ 
B) -55.1 kJ 
C) 55.1 kJ 
D) 220.4 kJ 
A) -220.4 kJ 
B) -55.1 kJ 
C) 55.1 kJ 
D) 220.4 kJ

Exam 8: Thermochemistry: Chemical Energy

What are the signs of ΔH,ΔS,and ΔG for the following spontaneous change?

The following drawing is a representation of a reaction of the type A → B,where different shaded spheres represent different molecular structures.For this reaction ΔH° = -30 kJ.This reaction is likely to be

A process is carried out at constant pressure.Given that ΔE is positive and ΔH is negative,

An ideal gas expands into a vacuum (external pressure = 0)without gaining or losing heat.For this expansion

How much heat is absorbed/released when 35.00 g of NH3(g)reacts in the presence of excess O2(g)to produce NO(g)and H2O(l)according to the following chemical equation? 4 NH3(g)+ 5 O2(g)→ 4 NO(g)+ 6 H2O(l)ΔH° = 1168 kJ

A slice of cheese pizza has a caloric content of 150 Cal.If this energy could be used to power a 2500 Watt microwave oven,how many minutes could the microwave oven be operated?

The law of conservation of energy is also known as the ________ law of thermodynamics.

Calculate the work,w,gained or lost by the system when a gas expands from 15 L to 40 L against a constant external pressure of 1.5 atm.1 L ∙ atm = 101 J

The following drawing is a representation of a reaction for which ΔH° = -22 kJ.This reaction is likely to be

A reaction that absorbs 49.6 kJ from the surroundings in a vessel that undergoes a volume decrease of 1.25 L at a constant 4.00 atm pressure has an energy change,ΔE = ________ kJ.

At constant pressure,the combustion of 15.0 g of C2H6(g)releases 777 kJ of heat.What is ΔH for the reaction given below? 2 C2H6(g)+ 7 O2(g)→ 4 CO2(g)+ 6 H2O(l)

For which should the standard heat of formation ΔH°f,be zero at 25°C?

Which of the following is not true?

The sum of the potential and kinetic energies for every molecule or ion in a system is the ________ energy of the system and is given the symbol ________.

Given: S (s)+ O2 (g)→ SO2 (g)ΔH° = -296.1 kJ 2 SO3 (g)→ 2 SO2 (g)+ O2 (g)ΔH° = 198.2 kJ Find ΔH° for : 2 S(s)+ 3 O2(g)→ 2 SO3(g)

In the reaction shown below,________ kJ of heat are released per mole of O2(g)that reacts. C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(g)ΔH = -2045 kJ

10.0 g of a metal,initially at 25°C,are placed into 10.0 g of water,initially at 100°C.Which metal will have the highest final temperature? Shown after each metal is its specific heat in J/(g∙°C).

Which depends only on the initial and final state?

Given: 4 NO2(g)+ O2(g)→ 2 N2O5(g)ΔH° = -110.2 kJ Find ΔH° for N2O5(g)→ 2 NO2(g)+ 1/2 O2(g).

Chemistry: Matter and Measurement

Atoms, molecules, and Ions

Formulas, equations, and Moles

Reactions in Aqueous Solutions

Periodicity and the Atomic Structure of Atoms

Ionic Bonds and Some Main-Group Chemistry

Covalent Bonds and Molecular Structure

Gases: Their Properties and Behavior

Liquids,solids,and Phase Changes

Solutions and Their Properties

Chemical Kinetics

Chemical Equilibrium

Aqueous Equilibria: Acids and Bases

Applications of Aqueous Equilibria

Thermodynamics: Entropy, free Energy, and Equilibrium

Electrochemistry

Hydrogen, oxygen, and Water

The Main-Group Elements

Transition Elements and Coordination Chemistry

Metals and Solid-State Materials

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Filters

How much heat is absorbed/released when 35.00 g of NH₃(g)reacts in the presence of excess O₂(g)to produce NO(g)and H₂O(l)according to the following chemical equation? 4 NH₃(g)+ 5 O₂(g)→ 4 NO(g)+ 6 H₂O(l)ΔH° = 1168 kJ

At constant pressure,the combustion of 15.0 g of C₂H₆(g)releases 777 kJ of heat.What is ΔH for the reaction given below? 2 C₂H₆(g)+ 7 O₂(g)→ 4 CO₂(g)+ 6 H₂O(l)

For which should the standard heat of formation ΔH°_f,be zero at 25°C?

The sum of the potential and kinetic energies for every molecule or ion in a system is the energy of the system and is given the symbol .

Given: S (s)+ O₂ (g)→ SO₂ (g)ΔH° = -296.1 kJ 2 SO₃ (g)→ 2 SO₂ (g)+ O₂ (g)ΔH° = 198.2 kJ Find ΔH° for : 2 S(s)+ 3 O₂(g)→ 2 SO₃(g)

In the reaction shown below,________ kJ of heat are released per mole of O₂(g)that reacts. C₃H₈(g)+ 5 O₂(g)→ 3 CO₂(g)+ 4 H₂O(g)ΔH = -2045 kJ

Given: 4 NO₂(g)+ O₂(g)→ 2 N₂O₅(g)ΔH° = -110.2 kJ Find ΔH° for N₂O₅(g)→ 2 NO₂(g)+ 1/2 O₂(g).