Problem: Ammonium iodide can dissociate to produce HI and ammonia, NH4I(s) ⇌ NH3(g) + HI(g). At 300 °C, Kp = 0.42. If 250. g of ammonium iodide is placed into a 3.00 L flask and heated to 300 °C, what is the partial pressure of ammonia at equilibrium?a. 0.84 atm b. 0.21 atmc. 0.42 atmd. 0.65 atme. 0.18 atm

FREE Expert Solution

We’re being asked to determine the partial pressure of Ammonia when 250 g of NH4I is placed in a 3 L flasked heated up to 300°C

NH4I(s)  NH3(g) + HI(g)

Recall that the equilibrium constant is the ratio of the products and reactants.  We use Kp when dealing with pressure and Kc when dealing with concentration:

$\overline{){{\mathbf{K}}}_{{\mathbf{p}}}{\mathbf{=}}\frac{{\mathbf{P}}_{\mathbf{products}}}{{\mathbf{P}}_{\mathbf{reactants}}}}$     $\overline{){{\mathbf{K}}}_{{\mathbf{c}}}{\mathbf{=}}\frac{\mathbf{\left[}\mathbf{products}\mathbf{\right]}}{\mathbf{\left[}\mathbf{reactants}\mathbf{\right]}}}$

Note that solid and liquid compounds are ignored in the equilibrium expression.

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Problem Details

Ammonium iodide can dissociate to produce HI and ammonia, NH4I(s) ⇌ NH3(g) + HI(g). At 300 °C, Kp = 0.42. If 250. g of ammonium iodide is placed into a 3.00 L flask and heated to 300 °C, what is the partial pressure of ammonia at equilibrium?

a. 0.84 atm

b. 0.21 atm

c. 0.42 atm

d. 0.65 atm

e. 0.18 atm