Question 1

The standard state of a substance in aqueous solution is a 1 M solution.

Accepted Answer

A) True 
 B)False  True

Question 2

A system which undergoes an adiabatic change and has work done on it by the surroundings has

Accepted Answer

A) w = $\Delta$E 
B) w = -$\Delta$E 
C) w > 0,$\Delta$E  0 
E) w > $\Delta$E 
A) w = $\Delta$E 
B) w = -$\Delta$E 
C) w > 0,$\Delta$E  0 
E) w > $\Delta$E A

Question 3

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) -l000 J 
D) 1000 J 
E) 575 J 
A) -150 J 
B) 150 J 
C) -l000 J 
D) 1000 J 
E) 575 J B

Question 4

Consider the equation $\Delta$E = q + w
Explain fully the meaning of all three terms in the equation,and also the implied sign convention for q and w.

Accepted Answer

E is the internal energy of a system,i.e

Question 5

Nitric acid,which is among the top 15 chemicals produced in the United States,was first prepared over 1200 years ago by heating naturally occurring sodium nitrate (called saltpeter)with sulfuric acid and collecting the vapors produced.Calculate $\Delta$H°rxn for this reaction.$\Delta$H°f [NaNO3(s)] = -467.8 kJ/mol;$\Delta$H°f [NaHSO4(s)] = -1125.5 kJ/mol;$\Delta$H°f [H2SO4(l)= -814.0 kJ/mol;$\Delta$H°f [HNO3(g)] = -135.1 kJ/mol
NaNO3(s)+ H2SO4(l) $\to$ NaHSO4(s)+ HNO3(g)

Accepted Answer

A) -644.2 kJ 
B) -291.4 kJ 
C) -21.2 kJ 
D) 21.2 kJ 
E) 644.2 kJ 
A) -644.2 kJ 
B) -291.4 kJ 
C) -21.2 kJ 
D) 21.2 kJ 
E) 644.2 kJ

Question 6

Sand is converted to pure silicon in a three step process.The third step is
SiCl4(g)+ 2Mg(s) $\to$ 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 $\times$ l04 kJ 
D) -3.13 $\times$ 104 kJ 
E) None of these choices is correct. 
A) -25.0 kJ 
B) -7820 kJ 
C) -1.56 $\times$ l04 kJ 
D) -3.13 $\times$ 104 kJ 
E) None of these choices is correct.

Question 7

A system that does no work but which transfers heat to the surroundings has

Accepted Answer

A) q 0 B) q 0,$\Delta$E > 0 D) q > 0,$\Delta$E < 0 E) q < 0,$\Delta$E = 0 A) q 0 B) q 0,$\Delta$E > 0 D) q > 0,$\Delta$E < 0 E) q < 0,$\Delta$E = 0

Question 8

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°C is added to 50.0 mL of 0.500 M NaOH at 25.0°C in a coffee cup calorimeter,the temperature of the mixture rises to 28.2°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 9

Natural gas,or methane,is an important fuel.Combustion of one mole of methane releases 802.3 kilojoules of energy.How much energy does that represent in kilocalories?

Accepted Answer

A) 1.92 $\times$ 10-1 kcal 
B) 1.92 $\times$ 102 kcal 
C) 3.36 $\times$ 103 kcal 
D) 1.92 $\times$ 105 kcal 
E) 3.36 $\times$ 106 kcal 
A) 1.92 $\times$ 10-1 kcal 
B) 1.92 $\times$ 102 kcal 
C) 3.36 $\times$ 103 kcal 
D) 1.92 $\times$ 105 kcal 
E) 3.36 $\times$ 106 kcal

Question 10

A system contracts from an initial volume of 15.0 L to a final volume of 10.0 L under a constant external pressure of 0.800 atm.The value of w,in J,is

Accepted Answer

A) -4.0 J 
B) 4.0 J 
C) -405 J 
D) 405 J 
E) 4.05 $\times$ 103 J 
A) -4.0 J 
B) 4.0 J 
C) -405 J 
D) 405 J 
E) 4.05 $\times$ 103 J

Question 11

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°C,what is its final temperature?

Accepted Answer

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

Question 12

A system delivers 225 J of heat to the surroundings while delivering 645 J of work.Calculate the change in the internal energy,$\Delta$E,of the system.

Accepted Answer

A) -420 J 
B) 420 J 
C) -870 J 
D) 870 J 
E) -225 J 
A) -420 J 
B) 420 J 
C) -870 J 
D) 870 J 
E) -225 J

Question 13

A Snickers® candy bar contains 280 Calories,of which the fat content accounts for 120 Calories.What is the energy of the fat content,in kJ?

Accepted Answer

A) 5.0 $\times$ 10-1 kJ 
B) 29 kJ 
C) 5.0 $\times$ 102 kJ 
D) 1.2 $\times$ 103 kJ 
E) 5.0 $\times$ 105 kJ 
A) 5.0 $\times$ 10-1 kJ 
B) 29 kJ 
C) 5.0 $\times$ 102 kJ 
D) 1.2 $\times$ 103 kJ 
E) 5.0 $\times$ 105 kJ

Question 14

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°C and placed into a calorimeter containing 72.4 g of water at 23.6°C.The heat capacity of the calorimeter was 15.7 J/K.The final temperature in the calorimeter was 32.4°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 15

Which one of the following statements about standard states is incorrect?

Accepted Answer

A) The standard state of a solid compound is the pure solid. 
B) The standard state of a liquid compound is the pure liquid. 
C) The standard state of a gaseous compound is the gas at a pressure of 1 atmosphere. 
D) The standard state of an aqueous solute is a saturated solution in water. 
E) The standard state of an element is the form in which it is stable at 1 atm and a specified temperature,usually 25°C. 
A) The standard state of a solid compound is the pure solid. 
B) The standard state of a liquid compound is the pure liquid. 
C) The standard state of a gaseous compound is the gas at a pressure of 1 atmosphere. 
D) The standard state of an aqueous solute is a saturated solution in water. 
E) The standard state of an element is the form in which it is stable at 1 atm and a specified temperature,usually 25°C.

Question 16

Two solutions (the system),each of 25.0 mL volume and at 25.0°C,are mixed in a beaker.A reaction occurs between them,and the temperature rises to 35.0°C.After the products have equilibrated with the surroundings,the temperature is again 25.0°C and the total volume is 50.0 mL.No gases are involved in the reaction.Which one of the following relationships concerning the change from initial to final states (both at 25.0°C)is correct?

Accepted Answer

A) ($\Delta$E = 0) 
B) ($\Delta$H = 0) 
C) ($\Delta$E > 0) 
D) q = 0 
E) w = 0 
A) ($\Delta$E = 0) 
B) ($\Delta$H = 0) 
C) ($\Delta$E > 0) 
D) q = 0 
E) w = 0

Question 17

Diborane (B2H6)has been considered as a possible rocket fuel.Calculate $\Delta$H° for the reaction
B2H6(g) $\to$ 2B(s)+ 3H2(g)
using the following data:

Accepted Answer

The answer of Diborane (B2H6)has been considered as a possible...

Question 18

A mass of 1.250 g of benzoic acid (C7H6O2)was completely combusted in a bomb calorimeter.If the heat capacity of the calorimeter was 10.134 kJ/K and the heat of combustion of benzoic acid is -3226 kJ/mol,calculate (to three decimal places)the temperature increase that should have occurred in the apparatus.

Accepted Answer

Temperatur

Question 19

a.Starting from the equation H = E + PV,show how the relationship $\Delta$H = qp is derived.Clearly indicate any necessary assumptions or conditions.
b.In one sentence,state in full what is meant by the equation: $\Delta$H = qp.

Accepted Answer

a.Since H = E + PV (defining equation fo

Question 20

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

The standard state of a substance in aqueous solution is a 1 M solution.

A system which undergoes an adiabatic change and has work done on it by the surroundings has

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.

Consider the equation $\Delta$ E = q + w Explain fully the meaning of all three terms in the equation,and also the implied sign convention for q and w.

Sand is converted to pure silicon in a three step process.The third step is SiCl₄(g)+ 2Mg(s) $\to$ 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?

A system that does no work but which transfers heat to the surroundings has

Natural gas,or methane,is an important fuel.Combustion of one mole of methane releases 802.3 kilojoules of energy.How much energy does that represent in kilocalories?

A system contracts from an initial volume of 15.0 L to a final volume of 10.0 L under a constant external pressure of 0.800 atm.The value of w,in J,is

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°C,what is its final temperature?

A system delivers 225 J of heat to the surroundings while delivering 645 J of work.Calculate the change in the internal energy, $\Delta$ E,of the system.

A Snickers® candy bar contains 280 Calories,of which the fat content accounts for 120 Calories.What is the energy of the fat content,in kJ?

Which one of the following statements about standard states is incorrect?

a.Starting from the equation H = E + PV,show how the relationship $\Delta$ H = q_p is derived.Clearly indicate any necessary assumptions or conditions. b.In one sentence,state in full what is meant by the equation: $\Delta$ H = q_p.

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

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 Solutions

The Main-Group Elements: Applying Principles of Bonding and Structure

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 Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

Exam 6: Thermochemistry: Energy Flow and Chemical Change

The standard state of a substance in aqueous solution is a 1 M solution.

A system which undergoes an adiabatic change and has work done on it by the surroundings has

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.

Consider the equation Δ\DeltaΔ E = q + w Explain fully the meaning of all three terms in the equation,and also the implied sign convention for q and w.

Sand is converted to pure silicon in a three step process.The third step is SiCl4(g)+ 2Mg(s) →\to→ 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?

A system that does no work but which transfers heat to the surroundings has

Natural gas,or methane,is an important fuel.Combustion of one mole of methane releases 802.3 kilojoules of energy.How much energy does that represent in kilocalories?

A system contracts from an initial volume of 15.0 L to a final volume of 10.0 L under a constant external pressure of 0.800 atm.The value of w,in J,is

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°C,what is its final temperature?

A system delivers 225 J of heat to the surroundings while delivering 645 J of work.Calculate the change in the internal energy, Δ\DeltaΔ E,of the system.

A Snickers® candy bar contains 280 Calories,of which the fat content accounts for 120 Calories.What is the energy of the fat content,in kJ?

Which one of the following statements about standard states is incorrect?

Diborane (B2H6)has been considered as a possible rocket fuel.Calculate Δ\DeltaΔ H° for the reaction B2H6(g) →\to→ 2B(s)+ 3H2(g) using the following data:

a.Starting from the equation H = E + PV,show how the relationship Δ\DeltaΔ H = qp is derived.Clearly indicate any necessary assumptions or conditions. b.In one sentence,state in full what is meant by the equation: Δ\DeltaΔ H = qp.

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

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 Solutions

The Main-Group Elements: Applying Principles of Bonding and Structure

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 Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

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.

Consider the equation $\Delta$ E = q + w Explain fully the meaning of all three terms in the equation,and also the implied sign convention for q and w.

Sand is converted to pure silicon in a three step process.The third step is SiCl₄(g)+ 2Mg(s) $\to$ 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?

A system delivers 225 J of heat to the surroundings while delivering 645 J of work.Calculate the change in the internal energy, $\Delta$ E,of the system.

a.Starting from the equation H = E + PV,show how the relationship $\Delta$ H = q_p is derived.Clearly indicate any necessary assumptions or conditions. b.In one sentence,state in full what is meant by the equation: $\Delta$ H = q_p.