Question 1

$\Delta$E values obtained by bomb calorimetry can be converted to give accurate $\Delta$H values.

Accepted Answer

A) True 
 B)False

Question 2

A common laboratory reaction is the neutralization of an acid with a base. When 50.0 mL of 0.500 M HCl at 25.0$\degree$C is added to 50.0 mL of 0.500 M NaOH at 25.0$\degree$C in a coffee cup calorimeter, the temperature of the mixture rises to 28.2$\degree$C. What is the heat of reaction per mole of acid? Assume the mixture has a specific heat capacity of 4.18 J/(g ? K) and that the densities of the reactant solutions are both 1.00 g/mL.

Accepted Answer

A)  670 J 
B)  1300 J 
C)  27 kJ 
D)  54 kJ 
E)  > 100 kJ 
A)  670 J 
B)  1300 J 
C)  27 kJ 
D)  54 kJ 
E)  > 100 kJ

Question 3

Starting from equations relating pressure to force and force to work, derive the relationship w = -P$\Delta$V, explaining the steps in your argument.

Accepted Answer

Consider the system being contained in a

Question 4

and does work on the surroundings has:

Accepted Answer

A) w 0, $\Delta$E > 0 C) w > 0, $\Delta$E 0 E) w < 0, $\Delta$E < 0 A) w 0, $\Delta$E > 0 C) w > 0, $\Delta$E 0 E) w < 0, $\Delta$E < 0

Question 5

Sand is converted to pure silicon in a three step process. The third step is SiCl4(g) + 2Mg(s) $\rightarrow$2MgCl2(s) + Si(s), $\Delta$H = -625.6 kJ
What is the enthalpy change when 25.0 mol of silicon tetrachloride is converted to elemental silicon?

Accepted Answer

A)  -25.0 kJ 
B)  -7820 kJ 
C)  -1.56 * 104 kJ 
D)  -3.13 * 104 kJ 
E)  None of these choices is correct. 
A)  -25.0 kJ 
B)  -7820 kJ 
C)  -1.56 * 104 kJ 
D)  -3.13 * 104 kJ 
E)  None of these choices is correct.

Question 6

Calculate, in J, the work done by 10.0 g of CO2 when it sublimes against a pressure of 1.00 atm to form gaseous CO2 at 0.0$\degree$C. The volume of CO2(s) can be neglected; CO2(g) can be assumed to behave ideally. The process occurring is CO2(s) $\rightarrow$CO2(g)

Accepted Answer

Question 7

A system receives 575 J of heat and delivers 425 J of work. Calculate the change in the internal energy, $\Delta$E, of the system.

Accepted Answer

A)  -150 J 
B)  150 J 
C)  -1000 J 
D)  1000 J 
E)  575 J 
A)  -150 J 
B)  150 J 
C)  -1000 J 
D)  1000 J 
E)  575 J

Question 8

The Starship Enterprise is caught in a time warp and Spock is forced to use the primitive techniques of the 20th century to determine the specific heat capacity of an unknown mineral. The 307-g sample was heated to 98.7$\degree$C and placed into a calorimeter containing 72.4 g of water at 23.6$\degree$C. The heat capacity of the calorimeter was 15.7 J/K. The final temperature in the calorimeter was 32.4$\degree$C. What is the specific heat capacity of the mineral?

Accepted Answer

A)  0.124 J/(g ? K) 
B)  0.131 J/(g ? K) 
C)  0.138 J/(g ? K) 
D)  0.145 J/(g ? K) 
E)  None of these choices is correct. 
A)  0.124 J/(g ? K) 
B)  0.131 J/(g ? K) 
C)  0.138 J/(g ? K) 
D)  0.145 J/(g ? K) 
E)  None of these choices is correct.

Question 9

Although internal energy (E) is more fundamental and conceptually easier than enthalpy (H), in most chemical applications $\Delta$H is more relevant and useful than$\Delta$E. Why?

Accepted Answer

Most chemical processes of interest occu

Question 10

A) State Hess's Law.
B) Use the $\Delta$H$\degree$
 data given below to calculate $\Delta$H$\degree$
or the reaction:
C2H4(g) + H2(g) $\rightarrow$ C2H6(g)

Accepted Answer

a. The enthalpy change for an

Question 11

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings. If the initial internal energy, E, is 61.2 kJ, what is the final value of E?

Accepted Answer

A)  32.7 kJ 
B)  46.5 kJ 
C)  75.9 kJ 
D)  82.8 kJ 
E)  89.7 kJ 
A)  32.7 kJ 
B)  46.5 kJ 
C)  75.9 kJ 
D)  82.8 kJ 
E)  89.7 kJ

Question 12

Benzene is a starting material in the synthesis of nylon fibers and polystyrene (styrofoam). Its specific heat capacity is 1.74 J/(g ? K). If 16.7 kJ of energy is absorbed by a 225-g sample of benzene at 20.0$\degree$C, what is its final temperature?

Accepted Answer

A)  -22.7$\degree$C 
B)  36.7$\degree$C 
C)  42.7$\degree$C 
D)  62.7$\degree$C 
E)  None of these choices is correct. 
A)  -22.7$\degree$C 
B)  36.7$\degree$C 
C)  42.7$\degree$C 
D)  62.7$\degree$C 
E)  None of these choices is correct.

Question 13

The standard heat (enthalpy) of formation of graphite is zero.

Accepted Answer

A) True 
 B)False

Question 14

A system delivers 1275 J of heat while the surroundings perform 855 J of work on it. Calculate $\Delta$E in J.

Accepted Answer

A)  -2130 J 
B)  -420 J 
C)  420 J 
D)  2130 J 
E)  -1275 J 
A)  -2130 J 
B)  -420 J 
C)  420 J 
D)  2130 J 
E)  -1275 J

Question 15

Cold packs, whose temperatures are lowered when ammonium nitrate dissolves in water, are carried by athletic trainers when transporting ice is not possible. Which of the following is true of this reaction?

Accepted Answer

A)  ($\Delta$H  0, process is exothermic) 
C)  ($\Delta$H  0, process is endothermic) 
E)  ($\Delta$H = 0, since cold packs are sealed) 
A)  ($\Delta$H  0, process is exothermic) 
C)  ($\Delta$H  0, process is endothermic) 
E)  ($\Delta$H = 0, since cold packs are sealed)

Question 16

Calculate the enthalpy change for the reaction   from the following data:

Accepted Answer

A)  -551.6 kJ 
B)  -304.1 kJ 
C)  190.9 kJ 
D)  153.8 kJ 
E)  438.4 kJ 
A)  -551.6 kJ 
B)  -304.1 kJ 
C)  190.9 kJ 
D)  153.8 kJ 
E)  438.4 kJ

Question 17

Calculate the $\Delta$HS1U1B1fS1U1B0$\degree$rxnS1U1B0 for the decomposition of calcium carbonate to calcium oxide and carbon dioxide. 
$\Delta$HS1U1B1f S1U1B0$\degree$[CaCOS1U1B13S1U1B0(s)] = -1206.9 kJ/mol; $\Delta$HfS1U1B1$\degree$[S1U1B0CaO(s)] = -635.1 kJ/mol; $\Delta$HS1U1B1fS1U1B0B0 [COS1U1B12S1U1B0(g)] = -393.5 kJ/mol. CaCOS1U1B13S1U1B0(s)$\rightarrow$CaO(s) + COS1U1B12S1U1B0(g)

Accepted Answer

A)  -2235.5 kJ 
B)  -1448.5 kJ 
C)  -178.3 kJ 
D)  178.3 kJ 
E)  2235.5 kJ 
A)  -2235.5 kJ 
B)  -1448.5 kJ 
C)  -178.3 kJ 
D)  178.3 kJ 
E)  2235.5 kJ

Question 18

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. The work (w) done by the system, in J, is:

Accepted Answer

A)  1.00 J 
B)  2.00 J 
C)  1.01 * 102 J 
D)  1.01 * 105 J 
E)  None of these choices is correct. 
A)  1.00 J 
B)  2.00 J 
C)  1.01 * 102 J 
D)  1.01 * 105 J 
E)  None of these choices is correct.

Question 19

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.$\degree$C. The surrounding air is at the same pressure, but its temperature is 25$\degree$C. When the system has equilibrated with its surroundings, both systems and surroundings are at 25$\degree$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)  ($\Delta$E  0 
E)  q > 0 
A)  ($\Delta$E  0 
E)  q > 0

Question 20

A 275-g sample of nickel at 100.0$\degree$C is placed in 100.0 mL of water at 22.0$\degree$C. What is the final temperature of the water? Assume that no heat is lost to or gained from the surroundings. Specific heat capacity of nickel = 0.444 J/(g ? K)

Accepted Answer

A)  39.6$\degree$C 
B)  40.8$\degree$C 
C)  61.0$\degree$C 
D)  79.2$\degree$C 
E)  82.4$\degree$C 
A)  39.6$\degree$C 
B)  40.8$\degree$C 
C)  61.0$\degree$C 
D)  79.2$\degree$C 
E)  82.4$\degree$C

$\Delta$ E values obtained by bomb calorimetry can be converted to give accurate $\Delta$ H values.

Starting from equations relating pressure to force and force to work, derive the relationship w = -P $\Delta$ V, explaining the steps in your argument.

and does work on the surroundings has:

Sand is converted to pure silicon in a three step process. The third step is SiCl₄(g) + 2Mg(s) $\rightarrow$ 2MgCl₂(s) + Si(s), $\Delta$ H = -625.6 kJ What is the enthalpy change when 25.0 mol of silicon tetrachloride is converted to elemental silicon?

Calculate, in J, the work done by 10.0 g of CO₂ when it sublimes against a pressure of 1.00 atm to form gaseous CO₂ at 0.0 $\degree$ C. The volume of CO₂(s) can be neglected; CO₂(g) can be assumed to behave ideally. The process occurring is CO₂(s) $\rightarrow$ CO₂(g)

A system receives 575 J of heat and delivers 425 J of work. Calculate the change in the internal energy, $\Delta$ E, of the system.

Although internal energy (E) is more fundamental and conceptually easier than enthalpy (H), in most chemical applications $\Delta$ H is more relevant and useful than $\Delta$ E. Why?

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings. If the initial internal energy, E, is 61.2 kJ, what is the final value of E?

Benzene is a starting material in the synthesis of nylon fibers and polystyrene (styrofoam). Its specific heat capacity is 1.74 J/(g ? K). If 16.7 kJ of energy is absorbed by a 225-g sample of benzene at 20.0 $\degree$ C, what is its final temperature?

The standard heat (enthalpy) of formation of graphite is zero.

A system delivers 1275 J of heat while the surroundings perform 855 J of work on it. Calculate $\Delta$ E in J.

Cold packs, whose temperatures are lowered when ammonium nitrate dissolves in water, are carried by athletic trainers when transporting ice is not possible. Which of the following is true of this reaction?

Calculate the enthalpy change for the reaction from the following data:

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. The work (w) done by the system, in J, is:

A 275-g sample of nickel at 100.0 $\degree$ C is placed in 100.0 mL of water at 22.0 $\degree$ C. What is the final temperature of the water? Assume that no heat is lost to or gained from the surroundings. Specific heat capacity of nickel = 0.444 J/(g ? K)

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Exam 6: Thermochemistry: Energy Flow and Chemical Change

Δ\DeltaΔ E values obtained by bomb calorimetry can be converted to give accurate Δ\DeltaΔ H values.

Starting from equations relating pressure to force and force to work, derive the relationship w = -P Δ\DeltaΔ V, explaining the steps in your argument.

and does work on the surroundings has:

Sand is converted to pure silicon in a three step process. The third step is SiCl4(g) + 2Mg(s) →\rightarrow→ 2MgCl2(s) + Si(s), Δ\DeltaΔ H = -625.6 kJ What is the enthalpy change when 25.0 mol of silicon tetrachloride is converted to elemental silicon?

Calculate, in J, the work done by 10.0 g of CO2 when it sublimes against a pressure of 1.00 atm to form gaseous CO2 at 0.0 °\degree° C. The volume of CO2(s) can be neglected; CO2(g) can be assumed to behave ideally. The process occurring is CO2(s) →\rightarrow→ CO2(g)

A system receives 575 J of heat and delivers 425 J of work. Calculate the change in the internal energy, Δ\DeltaΔ E, of the system.

Although internal energy (E) is more fundamental and conceptually easier than enthalpy (H), in most chemical applications Δ\DeltaΔ H is more relevant and useful than Δ\DeltaΔ E. Why?

A) State Hess's Law. B) Use the Δ\DeltaΔ H °\degree° data given below to calculate Δ\DeltaΔ H °\degree° or the reaction: C2H4(g) + H2(g) →\rightarrow→ C2H6(g)

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings. If the initial internal energy, E, is 61.2 kJ, what is the final value of E?

Benzene is a starting material in the synthesis of nylon fibers and polystyrene (styrofoam). Its specific heat capacity is 1.74 J/(g ? K). If 16.7 kJ of energy is absorbed by a 225-g sample of benzene at 20.0 °\degree° C, what is its final temperature?

The standard heat (enthalpy) of formation of graphite is zero.

A system delivers 1275 J of heat while the surroundings perform 855 J of work on it. Calculate Δ\DeltaΔ E in J.

Cold packs, whose temperatures are lowered when ammonium nitrate dissolves in water, are carried by athletic trainers when transporting ice is not possible. Which of the following is true of this reaction?

Calculate the enthalpy change for the reaction from the following data:

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. The work (w) done by the system, in J, is:

A 275-g sample of nickel at 100.0 °\degree° C is placed in 100.0 mL of water at 22.0 °\degree° C. What is the final temperature of the water? Assume that no heat is lost to or gained from the surroundings. Specific heat capacity of nickel = 0.444 J/(g ? K)

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Equilibrium: the Extent of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

$\Delta$ E values obtained by bomb calorimetry can be converted to give accurate $\Delta$ H values.

Starting from equations relating pressure to force and force to work, derive the relationship w = -P $\Delta$ V, explaining the steps in your argument.

Sand is converted to pure silicon in a three step process. The third step is SiCl₄(g) + 2Mg(s) $\rightarrow$ 2MgCl₂(s) + Si(s), $\Delta$ H = -625.6 kJ What is the enthalpy change when 25.0 mol of silicon tetrachloride is converted to elemental silicon?

Calculate, in J, the work done by 10.0 g of CO₂ when it sublimes against a pressure of 1.00 atm to form gaseous CO₂ at 0.0 $\degree$ C. The volume of CO₂(s) can be neglected; CO₂(g) can be assumed to behave ideally. The process occurring is CO₂(s) $\rightarrow$ CO₂(g)

A system receives 575 J of heat and delivers 425 J of work. Calculate the change in the internal energy, $\Delta$ E, of the system.

Although internal energy (E) is more fundamental and conceptually easier than enthalpy (H), in most chemical applications $\Delta$ H is more relevant and useful than $\Delta$ E. Why?

Benzene is a starting material in the synthesis of nylon fibers and polystyrene (styrofoam). Its specific heat capacity is 1.74 J/(g ? K). If 16.7 kJ of energy is absorbed by a 225-g sample of benzene at 20.0 $\degree$ C, what is its final temperature?

A system delivers 1275 J of heat while the surroundings perform 855 J of work on it. Calculate $\Delta$ E in J.

A 275-g sample of nickel at 100.0 $\degree$ C is placed in 100.0 mL of water at 22.0 $\degree$ C. What is the final temperature of the water? Assume that no heat is lost to or gained from the surroundings. Specific heat capacity of nickel = 0.444 J/(g ? K)