Question

CHM 202 HW 8 F 19 1. A reaction mixture at 350 C was found to have the following concentrations: [HI] -0.024 M; [Hz] -0.025 M and [1-0,025 M H (s) b) = 2 Hl(e), K. = 57.0 a) Determine whether the mixture is at equilibrium or not b) if the mixture is not at equilibrium, tell the direction of the shift to reach equilibrium, and calculate the equilibrium concentrations of H>, b and Hl. 2. Consider the Haber Process for the synthesis of ammonia from hydrogen and nitrogen: 3 H (g) + N2(g) + 2NH3(g) Show that the reaction would shift to the right if the pressure is doubled. 3. a) How would you drive the following reaction to the right to form more products: CO(g) + H20() CO2(g) + H2(g) AH = -40.3 kJ Ans. by One of the products is a 'bigh value substance' Which one, and what is it used for?

Answer 1

1.a) calculation of reaction quotient ( Qc )

= [ HI ] ² / [ H2] [ I2]

= (0.024 )² / ( 0.025 ) ( 0.025 ) = 0.9

Since Qc and Kc are not equal system is not present at equilibrium position.

b) Since Q_{​​​​​​c} < K_{​​​​​​c} , system will shift in forward direction to attain equilibrium.

Let x M of H2 and I2 are reacted so 2x M of HI will produce at equilibrium.at equilibrium

[ H2 ] = (0.025 - x )M

[ I2] = ( 0.025 - x ) M

[ HI ] = ( 0.024 + 2x ) M

Kc ={ ( 0.024 + 2x )² / ( 0.025 - x ) ( 0.025 - x ) } = 57

Solving this , x = 0.017 M

So equilibrium concentration are

[ H2 ] = [ I2 ] = 0.025 - 0.017 = 0.008 M

[ HI ] = 0.024 + 0.034 = 0.058 M

2) on doubling pressure reaction will shift in that direction where pressure decreases ( number of gaseous moles decreases ) since forward reaction has 2 moles and backward reaction has 4 moles it shift in forward direction to attain equilibrium.

3) since it is exothermic reaction , on decreasing temperature it move towards product side.