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would the equilibrium constant for reaction be the written as C + A + B? 4. The

ID: 553663 • Letter: W

Question

would the equilibrium constant for reaction be the written as C + A + B? 4. The equilibrium constant for the isomerization of cis-2-butene to trans-2-butene is K-2.07 at 400K. Calculate the standard reaction Gibbs energy (AG n) for the isomerization reaction. (Remember: (AGrn AG n+ RT In K) 5. At 525K, a 20.82 g sample of PCls is placed in a 5.00 L container. At equilibrium, 10.3 g PCl3 have formed. What is the value of K for the reaction? PCIs(g) PCl3(g) + Cl2(g) 6. Suppose a quantity of HI(g) was sealed in a 2.00 L container and brought to equilibrium at 698K. If K-54.3 for the reaction below, and [H11-0.0353M at equilibrium, a) determine the equilibrium concentration values for [H2] and [I2]. b) Also, what is the initial value of [HI]? H2(g) + 12(g) 2H1(g)

Explanation / Answer

4) At equillibrium

G = 0

G°rxn + RTlnK = 0

G°rxn = - RTlnK

= - (8.314(J/Kmol) × 400K× ln(2.07)

= - ( 8.314(J/Kmol) × 400K ×2.303 log(2.07))

= - 2.42kJ/mol

5) PCl5(g) <------> PCl3(g) + Cl2(g)

K = [PCl3][Cl2]/[PCl5]

Initial concentration of PCl5

Mass of PCl5 = 20.82g

Molar mass of PCl5 = 208.22g/mol

No of mole of PCl5 = 20.82g/208.22g/ml =0.09999

Volume of Container= 5L

[PCl5] = 0.09999mole/5L =0.0200M

at equillibrium

[ PCl5 ] = 0.0200 - x

[ Cl2 ] = x

[ PCl3 ] = x

Therefore,

K = x^2/(0.0200 - x )

at equillibrium

mass of PCl3 = 10.3g

No of mole of PCl3 =10.3g /137.33g/mol= 0.0750

[PCl3 ] = 0.0750M/5 L = 0.0150M

Therfore,

x = 0.0150

[PCl5] = 0.0200- 0.0150 = 0.0050M

[Cl2] = 0.0150M

[PCl3]= 0.0150M

K =( 0.015)^2/(0.0050)

= 0.045

6) a) H2(g) + I2(g) <-------> 2HI(g)

K = [HI]^2/[H2][I2]= 54.3

At equillibrium

54.3= (0.0353)^2/[H2][I2]

[H2] = x

[ I2 ] = x

x^2=( 0.0353)^2/54.3

= 2.29×10^-5

x = 0.0048

[ H2] = 0.0048M

[ I2 ] = 0.0048M