Question 1

Clearly state the thermodynamic standard state of
a.an element or compound.
b.a solute.

Accepted Answer

The answer of Clearly state the thermodynamic standard state of
a.an...

Question 2

When 1.00 g of solid NH₄Cl is dissolved in 25.00 g of water contained in a coffee cup calorimeter,both reagents initially being at 25.0°C,the temperature falls to 22.4°C.Assuming that the heat capacity of the ammonium chloride solution is 4.18 J/(g·K),calculate the heat (enthalpy)of solution of NH₄Cl, (a)in J/g and (b)in kJ/mol.

Accepted Answer

The answer of When 1.00 g of solid NH₄Cl is...

Question 3

An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide.$\Delta$H°f [NH3(g)] = -45.9 kJ/mol;$\Delta$H°f [NO(g)] = 90.3 kJ/mol;$\Delta$H°f [H2O(g)] = -241.8 kJ/mol
4NH3(g)+ 5O2(g) $\to$ 4NO(g)+ 6H2O(g)
Calculate $\Delta$H°rxn for this reaction.

Accepted Answer

A) -906.0 kJ 
B) -197.4 kJ 
C) -105.6 kJ 
D) 197.4 kJ 
E) 906.0 kJ

Question 4

A system initially has an internal energy E of 501 J.It undergoes a process during which it releases 111 J of heat energy to the surroundings,and does work of 222 J.What is the final energy of the system,in J?

Accepted Answer

A) 168 J 
B) 390 J 
C) 612 J 
D) 834 J 
E) It cannot be calculated without more information.

Question 5

The dissolution of barium hydroxide in water is an exothermic process.Which of the following statements is correct?

Accepted Answer

A) The enthalpy of solid barium hydroxide plus pure water is less than that of the solution,at the same temperature. 
B) The enthalpy of solid barium hydroxide plus pure water is greater than that of the solution,at the same temperature. 
C) The enthalpy of solid barium hydroxide plus pure water is the same as that of the solution,at the same temperature. 
D) The temperature of the solution is lower than of the barium hydroxide and water before mixing. 
E) When barium hydroxide dissolves in water,the system does work on the surroundings.

Question 6

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

Accepted Answer

A) True 
 B)False

Question 7

Calculate the enthalpy change for the reaction
NO(g)+ O(g) $\to$ NO2(g)
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

Question 8

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

Accepted Answer

A) True 
 B)False

Question 9

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

Question 10

The enthalpy (H)of liquid water is greater than that of the same quantity of ice at the same temperature.

Accepted Answer

A) True 
 B)False

Question 11

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°C.The volume of CO₂(s)can be neglected;CO₂(g)can be assumed to behave ideally.The process occurring is CO₂(s)$\to$CO₂(g)

Accepted Answer

The answer of Calculate,in J,the work done by 10.0 g...

Question 12

A piece of copper metal is initially at 100.0°C.It is dropped into a coffee cup calorimeter containing 50.0 g of water at a temperature of 20.0°C.After stirring,the final temperature of both copper and water is 25.0°C.Assuming no heat losses,and that the specific heat (capacity)of water is 4.18 J/(g·K),what is the heat capacity of the copper in J/K?

Accepted Answer

A) 2.79 J/K 
B) 3.33 J/K 
C) 13.9 J/K 
D) 209 J/K 
E) None of these choices is correct.

Question 13

The reaction 2NaOH(aq)+ H₂SO₄(aq) $\to$ Na₂SO₄(aq)+ 2H₂O(l) was studied in a coffee cup calorimeter.100.mL portions of 1.00 M aqueous NaOH and H₂SO₄,each at 24.0°C,were mixed.The maximum temperature achieved was 30.6°C.Neglect the heat capacity of the cup and the thermometer,and assume that the solution of products has a density of exactly 1 g/mL and a specific heat capacity of 4.18 J/(g·K). a.Calculate the heat of reaction,q,in J. b.Calculate $\Delta$H,the heat (enthalpy)of reaction,in kJ/mol of Na₂SO₄ produced.

Accepted Answer

The answer of The reaction 2NaOH(aq)+ H₂SO₄(aq) $\to$ Na₂SO₄(aq)+ 2H₂O(l) was studied...

Question 14

Calculate the $\Delta$H°rxn for the following reaction.$\Delta$H°f [AsH3(g)] = 66.4 kJ/mol;$\Delta$H°f [H3AsO4(aq)] =
-904.6 kJ/mol;$\Delta$H°f [H2O(l)] = -285.8 kJ/mol
H3AsO4(aq)+ 4H2(g) $\to$ AsH3(g)+ 4H2O(l)

Accepted Answer

A) -1981.4 kJ 
B) -685.2 kJ 
C) -172.2 kJ 
D) 172.2 kJ 
E) 685.2 kJ

Question 15

a.Explain fully what is meant by the term "state function."
b.(i)Give two examples of thermodynamic quantities which are state functions.
(ii)Give two examples of thermodynamic quantities which are not state functions.

Accepted Answer

The answer of a.Explain fully what is meant by the...

Question 16

a.Define,or explain fully what is meant by the standard enthalpy of formation of a substance,$\Delta$H°_f . b.What is the standard state of the element oxygen? c.Write down in full the formation reaction for liquid ethanol,C₂H₅OH(l).The equation should be balanced and should indicate the physical state of each substance.

Accepted Answer

The answer of a.Define,or explain fully what is meant by...

Question 17

A system that does no work but which receives heat from the surroundings has

Accepted Answer

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

Question 18

Calculate q when 28.6 g of water is heated from 22.0°C to 78.3°C.

Accepted Answer

A) 0.385 kJ 
B) 1.61 kJ 
C) 6.74 kJ 
D) 9.37 kJ 
E) 1.61 $\times$ 103 kJ

Question 19

Which of the following is not a state function?

Accepted Answer

A) internal energy 
B) volume 
C) work 
D) pressure 
E) enthalpy

Question 20

For a reaction in a sealed,rigid container,$\Delta$H is always greater than $\Delta$E.

Accepted Answer

A) True 
 B)False

Exam 6: Thermochemistry: Energy Flow and Chemical Change

Clearly state the thermodynamic standard state of a.an element or compound. b.a solute.

A system initially has an internal energy E of 501 J.It undergoes a process during which it releases 111 J of heat energy to the surroundings,and does work of 222 J.What is the final energy of the system,in J?

The dissolution of barium hydroxide in water is an exothermic process.Which of the following statements is correct?

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

Calculate the enthalpy change for the reaction NO(g) + O(g) $\to$ NO₂(g) From the following data: $Calculate the enthalpy change for the reaction NO(g) + O(g) \to NO<sub>2</sub>(g) From the following data: A) -551.6 kJ B) -304.1 kJ C) 190.9 kJ D) 153.8 kJ E) 438.4 kJ$

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

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

The enthalpy (H)of liquid water is greater than that of the same quantity of ice at the same temperature.

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°C.The volume of CO₂(s)can be neglected;CO₂(g)can be assumed to behave ideally.The process occurring is CO₂(s) $\to$ CO₂(g)

Calculate the $\Delta$ H°_rxn for the following reaction. $\Delta$ H°_f [AsH₃(g) ] = 66.4 kJ/mol; $\Delta$ H°_f [H₃AsO₄(aq) ] = -904.6 kJ/mol; $\Delta$ H°_f [H₂O(l) ] = -285.8 kJ/mol H₃AsO₄(aq) + 4H₂(g) $\to$ AsH₃(g) + 4H₂O(l)

a.Explain fully what is meant by the term "state function." b.(i)Give two examples of thermodynamic quantities which are state functions. (ii)Give two examples of thermodynamic quantities which are not state functions.

A system that does no work but which receives heat from the surroundings has

Calculate q when 28.6 g of water is heated from 22.0°C to 78.3°C.

Which of the following is not a state function?

For a reaction in a sealed,rigid container, $\Delta$ H is always greater than $\Delta$ E.

Exam 6: Thermochemistry: Energy Flow and Chemical Change

Clearly state the thermodynamic standard state of a.an element or compound. b.a solute.

A system initially has an internal energy E of 501 J.It undergoes a process during which it releases 111 J of heat energy to the surroundings,and does work of 222 J.What is the final energy of the system,in J?

The dissolution of barium hydroxide in water is an exothermic process.Which of the following statements is correct?

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

Calculate the enthalpy change for the reaction NO(g) + O(g) →\to→ NO2(g) From the following data:

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

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

The enthalpy (H)of liquid water is greater than that of the same quantity of ice at the same temperature.

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°C.The volume of CO2(s)can be neglected;CO2(g)can be assumed to behave ideally.The process occurring is CO2(s) →\to→ CO2(g)

Calculate the Δ\DeltaΔ H°rxn for the following reaction. Δ\DeltaΔ H°f [AsH3(g) ] = 66.4 kJ/mol; Δ\DeltaΔ H°f [H3AsO4(aq) ] = -904.6 kJ/mol; Δ\DeltaΔ H°f [H2O(l) ] = -285.8 kJ/mol H3AsO4(aq) + 4H2(g) →\to→ AsH3(g) + 4H2O(l)

a.Explain fully what is meant by the term "state function." b.(i)Give two examples of thermodynamic quantities which are state functions. (ii)Give two examples of thermodynamic quantities which are not state functions.

A system that does no work but which receives heat from the surroundings has

Calculate q when 28.6 g of water is heated from 22.0°C to 78.3°C.

Which of the following is not a state function?

For a reaction in a sealed,rigid container, Δ\DeltaΔ H is always greater than Δ\DeltaΔ E.

Calculate the enthalpy change for the reaction NO(g) + O(g) $\to$ NO₂(g) From the following data: $Calculate the enthalpy change for the reaction NO(g) + O(g) \to NO<sub>2</sub>(g) From the following data: A) -551.6 kJ B) -304.1 kJ C) 190.9 kJ D) 153.8 kJ E) 438.4 kJ$

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

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

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°C.The volume of CO₂(s)can be neglected;CO₂(g)can be assumed to behave ideally.The process occurring is CO₂(s) $\to$ CO₂(g)

Calculate the $\Delta$ H°_rxn for the following reaction. $\Delta$ H°_f [AsH₃(g) ] = 66.4 kJ/mol; $\Delta$ H°_f [H₃AsO₄(aq) ] = -904.6 kJ/mol; $\Delta$ H°_f [H₂O(l) ] = -285.8 kJ/mol H₃AsO₄(aq) + 4H₂(g) $\to$ AsH₃(g) + 4H₂O(l)

For a reaction in a sealed,rigid container, $\Delta$ H is always greater than $\Delta$ E.