Question 1

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C₂H₄ (g)+ 3O₂ (g)→ 2CO₂ (g)+ 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

Accepted Answer

The combustion of ethene decreases the number of gas molecules, leading to a decrease in entropy. Thus, ΔS° is negative.

Question 2

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C₂H₄(g)+ H₂(g)→ C₂H₆(g) Is __________ J/K∙ mol.

Accepted Answer

The answer of The value of ΔS° for the catalytic...

Question 3

The value of ΔS° for the reaction 2C (s, diamond)+ O₂ (g)→ 2CO (g) Is __________ J/K∙ mol.

Accepted Answer

The ΔS° value can be calculated using the formula:
ΔS° = ΣS°(products) - ΣS°(reactants)
Using standard entropy values from tables, we get:
ΔS° = 2S°(CO) - [2S°(C, diamond) + S°(O2)]
= 2(197.9 J/K∙mol) - [2(2.4 J/K∙mol) + 205.0 J/K∙mol]
= 395.8 J/K∙mol - 209.8 J/K∙mol
= +186.0 J/K∙mol
Rounding off to one decimal place, the answer is +185.9 J/K∙mol.

Question 4

The combustion of hydrogen in the presence of excess oxygen yields water: 2H₂(g)+ O₂(g)→ 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

Accepted Answer

The answer of The combustion of hydrogen in the presence...

Question 5

The value of ΔS° for the oxidation of carbon to carbon dioxide, C (s, graphite)+ O₂ (g)→ CO₂(g) Is __________ J/K∙ mol. The combustion of carbon, as in charcoal briquettes, in the presence of abundant oxygen produces carbon dioxide.

Accepted Answer

The answer of The value of ΔS° for the oxidation...

Question 6

If ΔG° for a reaction is greater than zero, then __________.

Accepted Answer

If ΔG° for a reaction is greater than zero, it means that the reaction is not spontaneous in the forward direction. This implies that the concentration of products is lower than that of reactants at equilibrium. Thus, the equilibrium constant K must be less than 1 to favor the formation of products.

Question 7

The value of ΔS° for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s, rhombic)+ O₂(g)→ SO₂(g) Is __________ J/K∙ mol.

Accepted Answer

The answer of The value of ΔS° for the oxidation...

Question 8

The value of ΔS° for the decomposition of gaseous sulfur dioxide to solid elemental sulfur and gaseous oxygen, SO₂(g)→ S (s, rhombic)+ O₂(g) Is __________ J/K∙ mol.

Accepted Answer

The decomposition of sulfur dioxide into solid sulfur and gaseous oxygen involves the formation of a solid from a gas, which decreases the disorder of the system, indicating a negative ΔS°. Among the given options, -11.6 J/K∙mol is the only negative value that reflects a decrease in entropy.

Question 9

The value of ΔS° for the formation of POCl₃ from its constituent elements, P₂(g)+ O₂ (g)+ 3Cl₂ (g)→ 2POCl₃ (g) Is __________ J/K∙ mol.

Accepted Answer

The answer of The value of ΔS° for the formation...

Question 10

Consider the reaction: NH₃ (g)+ HCl (g)→ NH₄Cl (s) Given the following table of thermodynamic data, determine the temperature (in °C)above which the reaction is nonspontaneous.

Accepted Answer

The answer of Consider the reaction: NH₃ (g)+ HCl (g)→...

Question 11

The value of ΔS° for the oxidation of carbon to carbon monoxide, 2C (s, graphite)+ O₂ (g)→ 2CO (g) Is __________ J/K∙ mol. Carbon monoxide is produced in the combustion of carbon with limited oxygen.

Accepted Answer

The answer of The value of ΔS° for the oxidation...

Question 12

The value of ΔS° for the decomposition of gaseous sulfur trioxide to solid elemental sulfur and gaseous oxygen, 2SO₃ (g)→ 2S (s, rhombic)+ 3O₂ (g) Is __________ J/K∙ mol.

Accepted Answer

The answer of The value of ΔS° for the decomposition...

Question 13

Consider the reaction: FeO (s)+ Fe (s)+ O₂ (g)→ Fe₂O₃ (s) Given the following table of thermodynamic data, determine the temperature (in °C)above which the reaction is nonspontaneous.

Accepted Answer

The answer of Consider the reaction: FeO (s)+ Fe (s)+...

Question 14

The combustion of acetylene in the presence of excess oxygen yields carbon dioxide and water: 2C₂H₂ (g)+ 5O₂ (g)→ 4CO₂ (g)+ 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

Accepted Answer

The answer of The combustion of acetylene in the presence...

Question 15

The value of ΔS° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s, rhombic)+ 3O₂(g)→ 2SO₃ (g) Is __________ J/K^∙ mol.

Accepted Answer

The answer of The value of ΔS° for the oxidation...

Question 16

Which one of the following statements is true about the equilibrium constant for a reaction if ΔG° for the reaction is negative?

Accepted Answer

A negative ΔG° indicates that the reaction is thermodynamically favorable, meaning that products are favored over reactants. This means that the equilibrium constant (K) will be greater than 1, indicating a higher concentration of products at equilibrium.

Question 17

The combustion of ethane in the presence of excess oxygen yields carbon dioxide and water: 2C₂H₆ (g)+ 7O₂ (g)→ 4CO₂ (g)+ 6H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

Accepted Answer

The answer of The combustion of ethane in the presence...

Question 18

With thermodynamics, one cannot determine __________.

Accepted Answer

Thermodynamics provides information about the direction, extent, and conditions (such as temperature) under which a reaction is spontaneous, as well as the value of the equilibrium constant. However, it does not provide information about the speed or kinetics of a reaction.

Question 19

The value of ΔS° for the catalytic hydrogenation of acetylene to ethene, C₂H₂ (g)+ H₂ (g)→ C₂H₄ (g) Is __________ J/K∙ mol.

Accepted Answer

The ΔS° value for this reaction can be calculated using the equation ΔS° = ΣS°(products) - ΣS°(reactants). The standard entropy of the reactants acetylene and hydrogen gas is higher than that of the product ethene. This means that the products are more ordered than the reactants, and there is a decrease in entropy (∆S° < 0) for this reaction. Therefore, the correct answer is (D) -112.0 J/K∙mol.

Question 20

The value of ΔS° for the catalytic hydrogenation of acetylene to ethane, C₂H₂ (g)+ 2H₂ (g)→ C₂H₆ (g) Is __________ J/K∙ mol.

Accepted Answer

ΔS° = ΣS°(products) - ΣS°(reactants)
We can find the standard entropy of formation for each compound using a table. Plug in the values and solve for ΔS°:
ΔS° = [2(S°(H2)) + S°(C2H2) + 2(S°(H2))] - [S°(C2H2) + 3(S°(H2))]
ΔS° = [(2)(130.7 J/K·mol) + 200.8 J/K·mol + (2)(130.7 J/K·mol))] - [200.8 J/K·mol + (3)(130.7 J/K·mol)]
ΔS° = - 232.5 J/K·mol

Quiz 19: Chemical Thermodynamics

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C₂H₄ (g) + 3O₂ (g) → 2CO₂ (g) + 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C₂H₄(g) + H₂(g) → C₂H₆(g) Is __________ J/K∙ mol.

The value of ΔS° for the reaction 2C (s, diamond) + O₂ (g) → 2CO (g) Is __________ J/K∙ mol.

The combustion of hydrogen in the presence of excess oxygen yields water: 2H₂(g) + O₂(g) → 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the oxidation of carbon to carbon dioxide, C (s, graphite) + O₂ (g) → CO₂(g) Is __________ J/K∙ mol. The combustion of carbon, as in charcoal briquettes, in the presence of abundant oxygen produces carbon dioxide.

If ΔG° for a reaction is greater than zero, then __________.

The value of ΔS° for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s, rhombic) + O₂(g) → SO₂(g) Is __________ J/K∙ mol.

The value of ΔS° for the decomposition of gaseous sulfur dioxide to solid elemental sulfur and gaseous oxygen, SO₂(g) → S (s, rhombic) + O₂(g) Is __________ J/K∙ mol.

The value of ΔS° for the formation of POCl₃ from its constituent elements, P₂(g) + O₂ (g) + 3Cl₂ (g) → 2POCl₃ (g) Is __________ J/K∙ mol.

Consider the reaction: NH₃ (g) + HCl (g) → NH₄Cl (s) Given the following table of thermodynamic data, determine the temperature (in °C) above which the reaction is nonspontaneous.

The value of ΔS° for the oxidation of carbon to carbon monoxide, 2C (s, graphite) + O₂ (g) → 2CO (g) Is __________ J/K∙ mol. Carbon monoxide is produced in the combustion of carbon with limited oxygen.

The value of ΔS° for the decomposition of gaseous sulfur trioxide to solid elemental sulfur and gaseous oxygen, 2SO₃ (g) → 2S (s, rhombic) + 3O₂ (g) Is __________ J/K∙ mol.

Consider the reaction: FeO (s) + Fe (s) + O₂ (g) → Fe₂O₃ (s) Given the following table of thermodynamic data, determine the temperature (in °C) above which the reaction is nonspontaneous.

The combustion of acetylene in the presence of excess oxygen yields carbon dioxide and water: 2C₂H₂ (g) + 5O₂ (g) → 4CO₂ (g) + 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s, rhombic) + 3O₂(g) → 2SO₃ (g) Is __________ J/K^∙ mol.

Which one of the following statements is true about the equilibrium constant for a reaction if ΔG° for the reaction is negative?

The combustion of ethane in the presence of excess oxygen yields carbon dioxide and water: 2C₂H₆ (g) + 7O₂ (g) → 4CO₂ (g) + 6H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

With thermodynamics, one cannot determine __________.

The value of ΔS° for the catalytic hydrogenation of acetylene to ethene, C₂H₂ (g) + H₂ (g) → C₂H₄ (g) Is __________ J/K∙ mol.

The value of ΔS° for the catalytic hydrogenation of acetylene to ethane, C₂H₂ (g) + 2H₂ (g) → C₂H₆ (g) Is __________ J/K∙ mol.

Quiz 19: Chemical Thermodynamics

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C2H4 (g) + 3O2 (g) → 2CO2 (g) + 2H2O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C2H4 (g) + H2(g) → C2H6 (g) Is __________ J/K∙ mol.

The value of ΔS° for the reaction 2C (s, diamond) + O2 (g) → 2CO (g) Is __________ J/K∙ mol.

The combustion of hydrogen in the presence of excess oxygen yields water: 2H2(g) + O2(g) → 2H2O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the oxidation of carbon to carbon dioxide, C (s, graphite) + O2 (g) → CO2(g) Is __________ J/K∙ mol. The combustion of carbon, as in charcoal briquettes, in the presence of abundant oxygen produces carbon dioxide.

If ΔG° for a reaction is greater than zero, then __________.

The value of ΔS° for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s, rhombic) + O2(g) → SO2(g) Is __________ J/K∙ mol.

The value of ΔS° for the decomposition of gaseous sulfur dioxide to solid elemental sulfur and gaseous oxygen, SO2 (g) → S (s, rhombic) + O2 (g) Is __________ J/K∙ mol.

The value of ΔS° for the formation of POCl3 from its constituent elements, P2 (g) + O2 (g) + 3Cl2 (g) → 2POCl3 (g) Is __________ J/K∙ mol.

Consider the reaction: NH3 (g) + HCl (g) → NH4Cl (s) Given the following table of thermodynamic data, determine the temperature (in °C) above which the reaction is nonspontaneous.

The value of ΔS° for the oxidation of carbon to carbon monoxide, 2C (s, graphite) + O2 (g) → 2CO (g) Is __________ J/K∙ mol. Carbon monoxide is produced in the combustion of carbon with limited oxygen.

The value of ΔS° for the decomposition of gaseous sulfur trioxide to solid elemental sulfur and gaseous oxygen, 2SO3 (g) → 2S (s, rhombic) + 3O2 (g) Is __________ J/K∙ mol.

Consider the reaction: FeO (s) + Fe (s) + O2 (g) → Fe2O3 (s) Given the following table of thermodynamic data, determine the temperature (in °C) above which the reaction is nonspontaneous.

The combustion of acetylene in the presence of excess oxygen yields carbon dioxide and water: 2C2H2 (g) + 5O2 (g) → 4CO2 (g) + 2H2O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s, rhombic) + 3O2(g) → 2SO3 (g) Is __________ J/K∙ mol.

Which one of the following statements is true about the equilibrium constant for a reaction if ΔG° for the reaction is negative?

The combustion of ethane in the presence of excess oxygen yields carbon dioxide and water: 2C2H6 (g) + 7O2 (g) → 4CO2 (g) + 6H2O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

With thermodynamics, one cannot determine __________.

The value of ΔS° for the catalytic hydrogenation of acetylene to ethene, C2H2 (g) + H2 (g) → C2H4 (g) Is __________ J/K∙ mol.

The value of ΔS° for the catalytic hydrogenation of acetylene to ethane, C2H2 (g) + 2H2 (g) → C2H6 (g) Is __________ J/K∙ mol.

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: C₂H₄ (g) + 3O₂ (g) → 2CO₂ (g) + 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the catalytic hydrogenation of ethene to ethane, C₂H₄(g) + H₂(g) → C₂H₆(g) Is __________ J/K∙ mol.

The value of ΔS° for the reaction 2C (s, diamond) + O₂ (g) → 2CO (g) Is __________ J/K∙ mol.

The combustion of hydrogen in the presence of excess oxygen yields water: 2H₂(g) + O₂(g) → 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the oxidation of carbon to carbon dioxide, C (s, graphite) + O₂ (g) → CO₂(g) Is __________ J/K∙ mol. The combustion of carbon, as in charcoal briquettes, in the presence of abundant oxygen produces carbon dioxide.

The value of ΔS° for the oxidation of solid elemental sulfur to gaseous sulfur dioxide, S (s, rhombic) + O₂(g) → SO₂(g) Is __________ J/K∙ mol.

The value of ΔS° for the decomposition of gaseous sulfur dioxide to solid elemental sulfur and gaseous oxygen, SO₂(g) → S (s, rhombic) + O₂(g) Is __________ J/K∙ mol.

The value of ΔS° for the formation of POCl₃ from its constituent elements, P₂(g) + O₂ (g) + 3Cl₂ (g) → 2POCl₃ (g) Is __________ J/K∙ mol.

Consider the reaction: NH₃ (g) + HCl (g) → NH₄Cl (s) Given the following table of thermodynamic data, determine the temperature (in °C) above which the reaction is nonspontaneous.

The value of ΔS° for the oxidation of carbon to carbon monoxide, 2C (s, graphite) + O₂ (g) → 2CO (g) Is __________ J/K∙ mol. Carbon monoxide is produced in the combustion of carbon with limited oxygen.

The value of ΔS° for the decomposition of gaseous sulfur trioxide to solid elemental sulfur and gaseous oxygen, 2SO₃ (g) → 2S (s, rhombic) + 3O₂ (g) Is __________ J/K∙ mol.

Consider the reaction: FeO (s) + Fe (s) + O₂ (g) → Fe₂O₃ (s) Given the following table of thermodynamic data, determine the temperature (in °C) above which the reaction is nonspontaneous.

The combustion of acetylene in the presence of excess oxygen yields carbon dioxide and water: 2C₂H₂ (g) + 5O₂ (g) → 4CO₂ (g) + 2H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the oxidation of solid elemental sulfur to gaseous sulfur trioxide, 2S (s, rhombic) + 3O₂(g) → 2SO₃ (g) Is __________ J/K^∙ mol.

The combustion of ethane in the presence of excess oxygen yields carbon dioxide and water: 2C₂H₆ (g) + 7O₂ (g) → 4CO₂ (g) + 6H₂O (l) The value of ΔS° for this reaction is __________ J/K∙ mol.

The value of ΔS° for the catalytic hydrogenation of acetylene to ethene, C₂H₂ (g) + H₂ (g) → C₂H₄ (g) Is __________ J/K∙ mol.

The value of ΔS° for the catalytic hydrogenation of acetylene to ethane, C₂H₂ (g) + 2H₂ (g) → C₂H₆ (g) Is __________ J/K∙ mol.