Question

1) For the chemical reaction, 2CH_4(g) <-->C₂H_2(g) + 3H_2(g) , K= 0.165 at1752^o C. What is K_p for the reaction at thistemperature?

2) For the reaction, N_2(g) + 3H_2(g)<--> 2NH_3(g) , K_p = 4.95 x10^-3 at 270^oC. What is K for the reaction atthis temperature?

Answer 1

1) For the chemical reaction, 2CH_4(g) <-->C₂H_2(g) + 3H_2(g) , K= 0.165 at1752^o C. What is K_p for the reaction at thistemperature?

We know that Kp = Kc * (RT) ^Δn

Where T = Temperature = 1752 o = 1752 + 273 = 2025K

R = gas constant = 0.0821 L atm / mol - K

Δn = No . of moles of gaseous products - No . of moles ofgaseous reactants

     = (1+3) - 2

     = 2

Plug the values we get Kp = 0.165 * ( 0.0821 * 2025 )²

                                        = 4.5605*10 ³

2) For the reaction, N_2(g) + 3H_2(g)<--> 2NH_3(g) , K_p = 4.95 x10^-3 at 270^oC. What is K for the reaction atthis temperature?

We know that Kp = Kc * (RT) ^Δn

Where T = Temperature = 270 o C = 270 + 273 =543K

R = gas constant = 0.0821 L atm / mol - K

Δn = No . of moles of gaseous products - No . of moles ofgaseous reactants

     = 2 - ( 1+3)

     =-2

Plug the values we get K = Kp *  (RT)^-Δn

                                      = 4.95 x 10^-3 * ( 0.0821 *543 ) ²

                                        = 9.837