Deck 11: Chemical Equilibria

Question 1

If $\Delta$ G ^$\circ$ = 27.1 kJ at 25 ^$\circ$ C for the reaction CH₃COOH(aq)+ H₂O(l) → CH₃COO^-(aq)+ H₃O⁺(aq)
What is K_a for this reaction at 298 K?

A)1.15 *10^-11
B)5.63 * 10⁴
C)1.78 * 10^-5
D)1.01
E)9.89 * 10^-1

Answer 1

1.78 * 10^-5

Question 2

The equilibrium constant for the reaction
HNO₂(aq)+ H₂O(l) →NO₂ $\rightarrow$ (aq)+ H₃O⁺(aq)
is 4.3 * 10^-4 at 25 ^$\circ$ C.Will nitrous acid spontaneously dissociate when
[HNO₂(aq)] = 1.0 M and [NO₂-(aq)] = [H₃O⁺(aq)] = 1.0 * 10^-5 M?
Show your calculations.

Answer 2

Yes

Question 3

Consider the reaction 2Fe₂O₃(s)+ 3C(s) $\rightarrow$ 4Fe(s)+ 3CO₂(g), $\Delta$ H ^$\circ$ = 462 kJ, $\Delta$ S ^$\circ$ = 558 J.K^-1
Calculate the equilibrium constant for this reaction at 525 ^$\circ$ C.

A)3.04 * 10^-3
B)8.07 * 10^-2
C)5.20 * 10^-7
D)1.9 * 10⁶
E)2.18 * 10^-2

Answer 3

8.07 * 10^-2

Question 4

The equilibrium constant expression for the reaction
CuSO₄(s) → CuO(s)+ SO₃(g)
is K = [CuO(s)][SO₃(g)]/[CuSO₄(s)].

Question 5

If a 1-L flask containing D₂(g),N₂(g),and ND₃(g)at equilibrium at 300 K and a 1-L flask of H₂(g),N₂(g),and NH₃(g)at equilibrium at 300 K are mixed,analysis of the reaction mixture shows that HD(g),NHD₂(g),and NH₂D(g)are also present.What conclusion(s)can be drawn?

Question 6

The equilibrium constant for the reaction
HNO₂(aq)+ H₂O(l) →NO₂ $\rightarrow$ (aq)+ H₃O⁺(aq)
is 4.3 * 10^-4 at 25 ^$\circ$ C.Will nitrous acid spontaneously dissociate when
[HNO₂(aq)] = [NO₂-(aq)] = [H₃O⁺(aq)] = 1.0 M? Show your calculations.

Question 7

Consider the reaction
CuSO₄(s) $\rightarrow$ CuO(s)+ SO₃(g)
If $\Delta$ G ^$\circ$ = -14.6 kJ at 950 ^$\circ$ C for this reaction,what is $\Delta$ G for an SO₃(g)pressure of 50 bar at this temperature?

A)2.68 kJ
B)25.2 kJ
C)54.4 kJ
D)16.3 kJ
E)-54.4 kJ

Question 8

Consider the reaction NO(g)+ O₂(g) $\rightarrow$ NO₂(g)
If $\Delta$ H ^$\circ$ = -56.52 kJ and $\Delta$ S ^$\circ$ = -72.60 J.K^-1 at 298 K,what is the equilibrium constant for the reaction at 298 K?

A)1.31 * 10⁶
B)7.63 * 10^-7
C)660
D)1.22 * 10¹⁴
E)8.08 * 10⁹

Question 9

Consider the following reaction at a certain temperature:
Ni(s)+ 4CO(g) →Ni(CO)₄(g)
Calculate K for this reaction if,at equilibrium,the partial pressures of CO(g)and Ni(CO)₄(g)are 1.25 and 6.65 atm over 1.00 kg of nickel.

Question 10

Consider the reaction
CuSO₄(s) $\rightarrow$ CuO(s)+ SO₃(g)
If $\Delta$ G ^$\circ$ = -14.6 kJ at 950 ^$\circ$ C for this reaction,what is $\Delta$ G for an SO₃(g)pressure of 20 bar at this temperature.

A)15.9 kJ
B)45.1 kJ
C)-14.6 kJ
D)30.5 kJ
E)-45.1 kJ

Question 11

Consider the reaction
2CuBr₂(s) $\rightarrow$ 2CuBr(s)+ Br₂(g)
If the equilibrium vapor pressure of Br₂(g)is 1.43 * 10^-5 Torr at 298 K,what is $\Delta$ G at this temperature when Br₂(g)is produced at a pressure of 7.50 * 10^-8 Torr.

A)-5.65 kJ
B)13.0 kJ
C)5.65 kJ
D)-3.42 kJ
E)-13.0 kJ

Question 12

For the equilibrium N₂O₄(g) →2NO₂(g),plot,on the same graph,the forward and reverse reaction rates as a function of time.If possible,mark on the graph where equilibrium is reached.

Question 13

Calculate $\Delta$ G at 298 K for the reaction C₂H₅OH(l) $\rightarrow$ C₂H₅OH(g,0.0263 bar)
Given $\Delta$ G ^$\circ$ = 6.2 kJ at 298 K.

A)6.2 kJ
B)15 kJ
C)2.8 kJ
D)-2.8 kJ
E)-15 kJ

Question 14

For the equilibrium CaCO₃(s) → CaO(s)+ CO₂(g),(a)represents the composition at equilibrium at a certain temperature.In (b),a small amount of Ca^*CO₃(s)has been added (Ca^*CO₃(s)represents Ca¹⁴CO₃(s)or labeled calcium carbonate).Draw the composition in (c)at equilibrium and explain your drawing.

Question 15

Calculate the value of K at 700 K for the reaction H₂(g)+ I₂(g) → 2HI(g)
Given that K_c = 54 at the same temperature.

A)3100
B)2.2
C)54
D)9.3
E)1300

Question 16

Calculate the equilibrium constant for the following reaction at 25 ^$\circ$ C 2TiCl₃(s)+ 2HCl(g) → 2TiCl₄(g)+ H₂(g)
Given $\Delta$ G ^$\circ$ = +46.6 kJ.

A)3.8 * 10^-98
B)1.5* 10^-19
C)6.7 * 10^-9
D)6.6 * 10¹⁸
E)1.5 * 10⁸

Question 17

Calculate $\Delta$ G at 298 K for the reaction C₂H₅OH(l) $\rightarrow$ C₂H₅OH(g,0.0400 bar)
Given $\Delta$ G ^$\circ$ = 6.2 kJ at 298 K.

A)14 kJ
B)2.7 kJ
C)-14 kJ
D)-1.8 kJ
E)1.8 kJ

Question 18

Consider the reaction
2CuBr₂(s) $\rightarrow$ 2CuBr(s)+ Br₂(g)
If the equilibrium vapor pressure of Br₂(g)is 1.43 * 10^-5 Torr at 298 K,what is $\Delta$ G at this temperature when Br₂(g)is produced at a pressure of 7.50 * 10^-7 Torr?

A)-7.31 kJ
B)7.31 kJ
C)39.9 kJ
D)-3.17 kJ
E)-4.15 kJ

Question 19

What is the relation between K and K_c for the reaction H₂(g)+ I₂(g) →2HI(g)

A)K = K_c
B)K = RTK_c
C)K_c = (RT)²K
D)K = (RT)²K_c
E)K_c = RTK

Question 20

If $\Delta$ G_r^o = 27.1 kJ∙mol^-1 at 25 ^$\circ$ C for the dissociation of acetic acid in aqueous solution,what is K for the reaction
CH₃COO^-(aq)+ H₃O⁺(aq) → CH₃COOH(aq)+ H₂O(l)

Question 21

Given: 4NH₃(g)+ 5O₂(g) → 4NO(g)+ 6H₂O(g)
K
Calculate the equilibrium constant for the following reaction.
2NH₃(g)+ O₂(g) →2NO(g)+ 3H₂O(g)

A)K
B)K^-1
C)2K
D)0.5K
E)K^1/2

Question 22

Given: 2SO₂(g)+ O₂(g) →2SO₃(g) At equilibrium at a certain temperature,the concentrations of SO₃(g),SO₂(g),and O₂(g)are 0.12 M,0.86 M,and 0.33 M,respectively.Calculate the value of K_c for this reaction.

A)1.31
B)0.42
C)0.014
D)0.059
E)0.87

Question 23

Given: C(s)+ CO₂(g) → 2CO(g) At equilibrium at a certain temperature,the partial pressures of CO(g)and CO₂(g)are 1.22 atm and 0.780 atm,respectively.Calculate the value of K for this reaction.

A)3.13
B)2.00
C)1.91
D)1.56
E)0.640

Question 24

At 600 ^$\circ$ C,the equilibrium constant for the reaction 2HgO(s) → 2Hg(l)+ O₂(g)
Is 2.8.Calculate the equilibrium constant for the reaction 1/2O₂(g)+ Hg(l) → HgO(s)

A)-1.7
B)1.1
C)0.60
D)0.36
E)1.7

Question 25

Given: 4NH₃(g)+ 5O₂(g) → 4NO(g)+ 6H₂O(g)
K
Calculate the equilibrium constant for the following reaction.
2NO(g)+ 3H₂O(g) →2NH₃(g)+ O₂(g)

A)-0.5K
B)-2K
C)K^-1/2
D)-K
E)K^-1

Question 26

At 25 ^$\circ$ C,K_c = 4.1 * 10⁸ for the reaction N₂(g)+ 3H₂(g) →2NH₃(g)
Calculate K at 25 ^$\circ$ C for this reaction.

A)9.7 * 10⁷
B)6.9 * 10⁵
C)4.1 * 10⁸
D)1.7 * 10⁹
E)2.5 * 10¹¹

Question 27

At 25 ^$\circ$ C,K = 6.9 * 10⁵ for the reaction N₂(g)+ 3H₂(g) →2NH₃(g)
Calculate K_c at 25 ^$\circ$ C for this reaction.

A)2.8 * 10⁴
B)6.8 * 10⁵
C)1.1 * 10³
D)1.7 * 10⁷
E)4.1 * 10⁸

Question 28

At 25 ^$\circ$ C,K_c = 1.58 * 10^-8 for the reaction NH₄(NH₂CO₂)(s)b 2NH₃(g)+ CO₂(g)
Calculate K at 25 ^$\circ$ C for this reaction.

A)3.87 * 10^-7
B)2.31 * 10^-4
C)9.45 * 10^-5
D)5.69 * 10^-3
E)1.36 * 10^-7

Question 29

Given: 2SO₂(g)+ O₂(g) →2SO₃(g) At equilibrium at a certain temperature,the concentrations of SO₃(g),SO₂(g),and O₂(g)are 0.24 M,0.82 M,and 0.33 M,respectively.Calculate the value of K_c for this reaction.

A)0.89
B)0.21
C)0.79
D)0.26
E)1.04

Question 30

Given: P₄(s)+ 6Cl₂(g)b 4PCl₃(l)
K
Calculate the equilibrium constant for the following reaction.
2PCl₃(l) →3Cl₂(g)+ P₄(s)

A)-K^1/2
B)1/K^1/2
C)1/K²
D)1/K
E)K^1/2

Question 31

The reaction free energy $\Delta$ G_r = $\Delta$ G°_r - RTln(K).

Question 32

What is the relationship between K and K_c for the reaction below? NH₄(NH₂CO₂)(s) →2NH₃(g)+ CO₂(g)

A)K_c = (RT)²K
B)K = RTK_c
C)K = (RT)²K_c
D)K = (RT)³K_c
E)K_c = (RT)³K

Question 33

The value of K for a given reaction is a constant and does not have units.

Question 34

At 700 K,K = 54 for the reaction H₂(g)+ I₂(g) →2HI(g)
Calculate K_c at 700 K for this reaction.

A)3.2 * 10^-4
B)0.94
C)7.7 * 10^-4
D)0.45
E)54

Question 35

The equilibrium constant,K,for the reaction 2HgO(s) → 2Hg(l)+ O₂(g)
Is 1.2 * 10^-30.Calculate K for the reaction
1/2O₂(g)+ Hg(l) → HgO(s).

A)-1.1 * 10^-15
B)8.3 * 10²⁹
C)4.2 * 10²⁹
D)9.1 * 10¹⁴
E)1.1 * 10^-15

Question 36

Given: SO₂(g) →O₂(g)+ S(s)
K_c = 2.5 * 10^-53
SO₃(g) → O₂(g)+ SO₂(g)
K_c = 4.0 * 10^-13
Calculate K_c for the reaction
2S(s)+ 3O₂(g) →2SO₃(g)

A)1.6 * 10¹⁰³
B)1.6 * 10⁸⁰
C)1.0 *10¹³⁰
D)1.6 * 10⁴⁰
E)1.0 * 10⁶⁵

Question 37

What is the relationship between K and K_c for the reaction below?
N₂(g)+ 3H₂(g) →2NH₃(g)

A)K = (RT)⁶K_c
B)K_c = (RT)^-2K
C)K_c = (RT)²K
D)K = (RT)^-2K_c
E)K = (RT)²K_c

Question 38

What is the relationship between K and K_c for the reaction below?
2HgO(s) → 2Hg(l)+ O₂(g)

A)K_c = (RT)²K
B)K = K_c
C)K_c = RTK
D)K = RTK_c
E)K = (RT)²K_c

Question 39

Given: C(s)+ CO₂(g) → 2CO(g) At equilibrium at a certain temperature,the partial pressures of CO(g)and CO₂(g)are 1.44 atm and 0.820 atm,respectively.Calculate the value of K for this reaction.

A)2.53
B)10.1
C)1.76
D)3.08
E)3.51

Question 40

At 600 ^$\circ$ C,K_c = 2.8 for the reaction 2HgO(s) → 2Hg(l)+ O₂(g)
Calculate K at 600 ^$\circ$ C for this reaction.

A)6800
B)200
C)1.4 * 10⁴
D)2.8
E)138

Question 41

At equilibrium,Q = K and $\Delta$ G°_r = 0.

Question 42

Consider the following reaction at a certain temperature:
PCl₅(g) →PCl₃(g)+ Cl₂(g)
K_c = 0.100
At equilibrium,[PCl₅] = 2.00 M and [PCl₃] = [Cl₂] = 1.00 M.If suddenly 1.00 M PCl₅(g),PCl₃(g),and Cl₂(g)is added,what is the equilibrium concentration of PCl₅(g)?

A)0.65 M
B)4.35 M
C)1.35 M
D)essentially zero
E)2.35 M

Question 43

The equilibrium constant,K_c,for the reaction 2NOCl(g) →2NO(g)+ Cl₂(g)
Is 0.51 at a certain temperature.A mixture of NOCl,NO,and Cl₂ with concentrations 1.3,1.2,and 0.60 M,respectively,was introduced into a container at this temperature.Which of the following is true?

A)Cl₂(g)is produced until equilibrium is reached.
B)[NOCl] = [NO] = [Cl₂] at equilibrium.
C)NOCl(g)is produced until equilibrium is reached.
D)[Cl₂] = 0.30 M at equilibrium.
E)No apparent reaction takes place.

Question 44

Consider the following reaction at a certain temperature:
PCl₅(g) →PCl₃(g)+ Cl₂(g)
K_c = 0.100
At equilibrium,[PCl₅] = 2.00 M and [PCl₃] = [Cl₂] = 1.00 M.If suddenly 1.00 M PCl₃(g)and Cl₂(g)is added,what is the equilibrium concentration of PCl₅(g)?

A)essentially 4.00 M
B)0.58 M
C)2.58 M
D)3.42 M
E)1.42 M

Question 45

The equilibrium constant,K_c,for the reaction 2SO₂(g)+ O₂(g) →2SO₃(g)
Is 11.7 at 1100 K.A mixture of SO₂,O₂,and SO₃,each with a concentration of 0.015 M,was introduced into a container at 1100 K.Which of the following is true?

A)SO₂(g)and O₂(g)will be formed until equilibrium is reached.
B)[SO₃] = 0.045 M at equilibrium.
C)[SO₃] = 0.015 M at equilibrium.
D)SO₃(g)will be formed until equilibrium is reached.
E)[SO₃] = [SO₂] = [O₂] at equilibrium.

Question 46

Which of the following statements is true?

A)When the value of Q is large,the equilibrium lies on the product side of the equilibrium reaction.
B)When the value of K is large,the equilibrium lies on the reactant side of the equilibrium reaction.
C)A small value of K means that the equilibrium concentrations of the reactants are small compared to the equilibrium concentrations of the products.
D)A large value of K means that the equilibrium concentrations of products are large compared to the equilibrium concentrations of the reactants.
E)When the value of K is small,the equilibrium lies on the product side of the equilibrium reaction.

Question 47

A mixture consisting of 0.250 M N₂(g)and 0.500 M H₂(g)reaches equilibrium according to the equation below: N₂(g)3H₂(g) → 2NH₃(g)
At equilibrium,the concentration of ammonia is 0.150 M.Calculate the concentration of N₂(g)at equilibrium.

A)0.150 M
B)0.100 M
C)0.0750 M
D)0.0500 M
E)0.175 M

Question 48

The effect of a volume decrease on the reaction C(s)+ H₂O(g) → CO(g)+ H₂(g)
Is

A)that K decreases.
B)more CO(g)and H₂(g)are produced.
C)no change.
D)more H₂O(g)is produced.
E)that K increases.

Question 49

Consider the reaction
Na⁺(g)+ Cl^-(g) → NaCl(s)
If the temperature is lowered,the products/reactants are favored.

Question 50

Consider the reaction
N₂(g)3H₂(g) →2NH₃(g)
If the initial concentrations of nitrogen and hydrogen are each 1.0 M,and X is the equilibrium concentration of ammonia,what is the correct equilibrium expression?

Question 51

A mixture consisting of 0.250 M N₂(g)and 0.500 M H₂(g)reaches equilibrium according to the equation below: N₂(g)3H₂(g) →2NH₃(g)
At equilibrium,the concentration of ammonia is 0.150 M.Calculate the concentration of H₂(g)at equilibrium.

A)0.0750 M
B)0.350 M
C)0.425 M
D)0.275 M
E)0.150 M

Question 52

Consider the reaction PCl₅(g) →PCl₃(g)+ Cl₂(g)
At a certain temperature,if the initial concentration of PCl₅(g)is 3.0 M,at equilibrium the concentration of Cl₂(g)is 0.80 M.Calculate the value of K_c at this temperature.

A)0.21
B)0.29
C)0.64
D)3.4
E)0.46

Question 53

For the reaction NH₃(g)+ H₂S(g) →NH₄HS(s)
K_c = 9.7 at 900 K.If the initial concentrations of NH₃(g)and H₂S(g)are 2.0 M,what is the equilibrium concentration of NH₃(g)?

A)1.9 M
B)1.7 M
C)0.20 M
D)0.10 M
E)0.32 M

Question 54

Consider the reaction PCl₅(g) →PCl₃(g)+ Cl₂(g)
At a certain temperature,if the initial concentration of PCl₅(g)is 2.0 M,at equilibrium the concentration of Cl₂(g)is 0.30 M.Calculate the value of K_c at this temperature.

A)0.064
B)0.053
C)0.090
D)19
E)0.045

Question 55

For the reaction 2CaSO₄(s) → 2CaO(s)+ 2SO₂(g)+ O₂(g)
K = 0.032 at 700 K.What is the total pressure starting from pure CaSO₄(s)?

A)0.22 bar
B)0.011 bar
C)0.60 bar
D)0.20 bar
E)0.40 bar

Question 56

Consider the following reaction: Ni(CO)₄(g) → Ni(s)+ 4CO(g)
If the initial concentration of Ni(CO)₄(g)is 1.0 M,and x is the equilibrium concentration of CO(g),what is the correct equilibrium relation?

A)K_c = X⁴/(1.0 - 4X)
B)K_c = X/(1.0 - X/4)
C)K_c = X⁴/(1.0 - X/4)
D)K_c = X⁵/(1.0 - X/4)
E)K_c = 4X/(1.0 -4X)

Question 57

Consider the following reaction at a certain temperature:
PCl₅(g) →PCl₃(g)+ Cl₂(g)
K_c = 0.100
At equilibrium,[PCl₅] = 2.00 M and [PCl₃] = [Cl₂] = 1.00 M.If suddenly 1.00 M PCl₅(g),PCl₃(g),and Cl₂(g)is added,what is the equilibrium concentration of Cl₂(g)?

A)3.0 M
B)essentially zero
C)0.65 M
D)2.75 M
E)3.35 M

Question 58

Write the equilibrium constant for 2NaBr(aq)+ Pb(ClO₄)₂(aq) →PbBr₂(s)+ 2NaClO₄(aq).

A)K = [Pb²⁺][Br^-2
B)K = 1/([Pb²⁺][Br^-2)
C)K = [NaClO₄]²/([NaBr]²[Pb(ClO₄)₂]
D)K = [PbBr₂]/([Pb²⁺][Br^-]²)
E)K = 1/([Pb(ClO₄)₂][NaBr]²)

Question 59

For the reaction NH₃(g)+ H₂S(g) →NH₄HS(s)
K_c = 9.7 at 900 K.If the initial concentrations of NH₃(g)and H₂S(g)are 2.0 M,what is the equilibrium concentration of H₂S(g)?

A)1.9 M
B)0.20 M
C)1.7 M
D)0.10 M
E)0.32 M

Question 60

Consider the reaction 3Fe(s)+ 4H₂O(g) → 4H₂(g)+ Fe₃O₄(s)
If the volume of the container is reduced,

A)the equilibrium constant increases.
B)more H₂(g)is produced.
C)no change occurs.
D)more H₂O(g)is produced.
E)more Fe(s)is produced.

Question 61

Consider the reaction CO(g)+ 2H₂(g) →CH₃OH(g)
At room temperature,K is approximately 2 * 10⁴,but at a higher temperature K is substantially smaller.Which of the following is true?

A)The reaction is endothermic.
B)The value of K_c for this reaction is smaller at all temperatures.
C)At the higher temperature,more CH₃OH(g)is produced.
D)The reaction is exothermic.
E)The reaction becomes spontaneous at higher temperatures.

Question 62

For the decomposition of ammonia to nitrogen and hydrogen,the equilibrium constant is 1.47 * 10^-6 at 298 K.Calculate the temperature at which K = 1.00.For this reaction, $\Delta$ H ^$\circ$ = 92.38 kJ.mol^-1.

A)193 K
B)353 K
C)466 K
D)492 K
E)219 K

Question 63

For the reaction 2NOCl(g) → 2NO(g)+ Cl₂(g),if,initially,[NOCl(g)] = 2.8 M,at equilibrium [NO(g)] = 1.2 M.Calculate the equilibrium concentration of NOCl(g).

Question 64

Consider the reaction 4NH₃(g)+ 3O₂(g) →2N₂(g)+ 6H₂O(g),K = 10⁸⁰ at a certain temperature.
Initially,all reactants and products have concentrations equal to 12 M.At equilibrium,the approximate concentration of ammonia is

A)6 M.
B)3 M.
C)12 M.
D)18 M.
E)0 M.

Question 65

For the reaction 2NOCl(g) → 2NO(g)+ Cl₂(g),K = 98 at a certain temperature.If the equilibrium concentrations in a 1 L container are [NOCl(g)] = 1.0 M,[NO(g)] = 3.5 M and [Cl₂(g)] = 8.0 M,and 2.0 mol of each gas is added,in which direction does the reaction shift?

Question 66

Consider the reaction
4NH₃(g)+ 7O₂(g) →2N₂O₄(g)+ 6H₂O(g)
If,initially,[NH₃(g)] = [O₂(g)] = 3.60 M,at equilibrium,[N₂O₄(g)] = 0.60 M.Calculate the equilibrium concentrations of all other species.

Question 67

The equilibrium constant K for the dissociation of N₂O₄(g)to NO₂(g)is 1700 at 500 K.Predict its value at 300 K.For this reaction, $\Delta$ H ^$\circ$ is 56.8 kJ.mol^-1.

A)1.32 * 10^-6
B)1.11 * 10^-4
C)15.5
D)0.188
E)1.54 * 10⁷

Question 68

Consider the reaction 4NH₃(g)+ 3O₂(g) →2N₂(g)+ 6H₂O(g),K = 10⁸⁰ at a certain temperature.
Initially,all reactants and products have concentrations equal to 12 M.At equilibrium,the approximate concentration of oxygen is

A)6 M.
B)0 M.
C)3 M.
D)12 M.
E)18 M.

Question 69

If the equilibrium constant for the reaction Ni(s)+ 4CO(g) →Ni(CO)₄(g)is 2.72 at a certain temperature,what is the equilibrium constant for the following reaction at the same temperature?
Ni(CO)₄(g) → Ni(s)+ 4CO(g)

Question 70

Consider the reaction below:
F₂(g) → 2F(g)
(a)Compressing the reaction mixture results in a change in Q.True or false?
(b)Heating the reaction mixture causes the reaction to shift to the left.True or false?
(c)At 1000 K,the equilibrium constant for the reaction is about 10^-4.If the reaction is perturbed such that Q = 1,the reaction must shift to the left.

Question 71

For the reaction N₂O₄(g) →2NO₂(g)
Which of the following disturbances will cause an increase in NO₂(g)concentration?

A)a decrease in temperature
B)need to know $\Delta$ H for the reaction to predict
C)removal of some N₂O₄(g)
D)an increase in pressure
E)an increase in temperature

Question 72

The vapor pressure of acetic acid at 25 ^$\circ$ C is 16 Torr. $\Delta$ G_r for the reaction CH₃COOH(l) →CH₃COOH(g)
At 25 ^$\circ$ C is

A)0
B)+9.57 kJ·mol^-1
C)-9.57 kJ·mol^-1
D)+1.85 kJ·mol^-1

Question 73

For any reaction at equilibrium, $\Delta$ G < 0.

Question 74

Consider the reaction 2HI(g) →H₂(g)+ I₂(g)
At 298 K,K_c = 1.3 *10^-3,whereas at 783 K,K_c = 2.2 * 10^-2.Which of the following is true?

A)The reaction is exothermic.
B)The reaction is endothermic.
C)At 298 K,K = 3.2 * 10^-2.
D)At 298 K,the reaction is likely to be spontaneous.
E)At 783 K,more HI(g)is produced.

Question 75

For a pure solid or liquid,the molar free energy always has its standard value.

Question 76

From a plot of Gibbs free energy versus progress of reaction,the sign of $\Delta$ G_r at any point along the curve is given by the slope of the curve.

Question 77

If a reaction mixture that is not at equilibrium contains more products than reactants, $\Delta$ G > 0 for the forward reaction.

Question 78

For the decomposition of ammonia to nitrogen and hydrogen,the equilibrium constant is 1.47 * 10^-6 at 298 K.Calculate the temperature at which K = 0.0100.For this reaction, $\Delta$ H ^$\circ$ = 92.38 kJ.mol^-1.

A)241 K
B)332 K
C)59 K
D)390 K
E)117 K

Question 79

Consider the following
N₂O₄(g) →2NO₂(g)
The equilibrium constant for this reaction will decrease with an increase in temperature.

Question 80

Consider the reaction Ni(s)+ 4CO(g) →Ni(CO)₄(g)
At 30 ^$\circ$ C and P_CO = 1 atm,Ni reacts with CO(g)to form Ni(CO)₄(g).At 200 ^$\circ$ C,Ni(CO)₄(g)decomposes to Ni(s)and CO(g).This means

A)adding an inert gas like argon favors the forward reaction.
B)the activation energy for the forward reaction is greater than for the reverse reaction.
C)the forward reaction is endothermic.
D)K at 30 ^$\circ$ C is greater than K at 200 ^$\circ$ C.
E)a decrease in pressure favors the forward reaction.