The Reaction Quotient Video Lessons

Example

# Problem: Consider the Haber process, 3 H2(g) + N2(g) ↔ 2 NH3(g). At a particular temperature, an equilibrium mixture contains 0.0030 M NH3(g), 0.10 M H2(g) and 0.090 M N2(g)? Which of the following statements best describes the reaction that will occur when(I) all 3 substances have concentrations of 0.40 M(II) all 3 substances have concentrations of 4.0 Ma. I will go to the left and II will go to the rightb. Both I and II will go to the leftc. II will go to the left and I will go to the rightd. Both I and II will go to the righte. I will go to the left and II is already at equilibrium

###### FREE Expert Solution

Use the concept of reaction quotient and calculate for the Kc using the equilibrium concentrations and determine what will happen if all species have a concentration of 0.40 or 4.0 M for the reaction:

3 H2(g) + N2(g) ↔ 2 NH3(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

Consider the Haber process, 3 H2(g) + N2(g) ↔ 2 NH3(g). At a particular temperature, an equilibrium mixture contains 0.0030 M NH3(g), 0.10 M H2(g) and 0.090 M N2(g)? Which of the following statements best describes the reaction that will occur when

(I) all 3 substances have concentrations of 0.40 M

(II) all 3 substances have concentrations of 4.0 M

a. I will go to the left and II will go to the right

b. Both I and II will go to the left

c. II will go to the left and I will go to the right

d. Both I and II will go to the right

e. I will go to the left and II is already at equilibrium