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1) M M [ PCl 5 ] = M [ PCl 3 ] = M [ Cl 2 ] = M 2) The equilibrium constant, K c

ID: 1043277 • Letter: 1

Question

1)

M

M

[PCl5] = M [PCl3] = M [Cl2] =

M

2) The equilibrium constant, Kc, for the following reaction is 55.6 at 698 K.

H2(g) + I2(g) 2 HI (g)

Calculate the equilibrium concentrations of reactants and product when 0.212moles of H2and 0.212 moles of I2are introduced into a 1.00 L vessel at 698 K.

[ H2] = M [ I2] = M [ HI ] =

M

3)The equilibrium constant, Kc, for the following reaction is 83.3 at 500 K.

PCl3(g) + Cl2(g) PCl5(g)

Calculate the equilibrium concentrations of reactant and products when 0.300moles of PCl3 and 0.300 moles of Cl2 are introduced into a 1.00 L vessel at 500 K.

[PCl3] = M [Cl2] = M [PCl5] = M

Explanation / Answer

1)                  

PCl5(g) ----------------- PCl3(g) + CL2(g)             Kc= 1.20x10^-2

0.358                          0              0

-x                                +x           +x

0.358-x                       +x             +x

Kc= [PCL3][Cl2]/[PCl5]

1.20x10^-2 = x*x/(0.358-x)

for solving the equation

x=0.0598

at equilibrium

number of moles of PCl5 = 0.358-0.0598 =0.2982 moles

number of moles of PCl3 = 0.0598 moles

number of moles of Cl2= 0.0598 moles

volume = 1.00L

[PCl5] = 0.2982/1.00= 0.2982M

[PCl3]= 0.0598/1.0= 0.0598M

[Cl2]= 0.0598/1.0= 0.0598M

2)

H2(g)    + I2(g) ------------------ 2 HI(g)                  Kc = 55.6

0.212        0.212                  0

-x               -x                    +2x

0.212-x      0.212-x               +2x

Kc= [HI]^2/[H2][I2]

55.6 = (2x)^2/(0.212-x)(0.212-x)

55.6 = [2x/(0.212-x)]^2

for solving the equation

x= 0.167

number of moles of H2= 0.212-0.167=0.045 moles

number o fmoles of I2 = 0.212-0.167=0.045 moles

number o fmole sof HI= 2x= 2x0.167 =0.334 moles

[H2] = 0.045/1.0= 0.045M

[I2]= 0.045M

[HI] = 0.334/1.0= 0.334M

3)

         PCl3(g)    + Cl2(g) ---------------- PCl5(g)

     0.300            0.3000                    0

             -x              -x                        +x

     0.300-x       0.300-x                    +x

Kc= [PCl5]/[PCl3][Cl2]

83.3= x*x/(0.300-x)

for solving the equation

x=0.299

[PCl3] 0.3-0.299=0.001M

[Cl2]== 0.3-0.299=0.001M

[PCl5] = 0.299M