Question

ammonium bisulfide

unreadable text describing the disturbance to the system

\\(\text{nh}_3(g) + \text{h}_2\text{s}(g) \
ightleftharpoons \text{nh}_4\text{hs}(s)\\)

\\(k = 400\\) at \\(35.0\\,^{\circ}\text{c}\\) \\(\delta h_{\text{rxn}} = -83.4\text{ kj}\\)

how does the concentration of \\(\text{nh}_3\\) change when the equilibrium is disturbed as described?

• the \\(\text{nh}_3\\) concentration increases.
• the \\(\text{nh}_3\\) concentration remains unchanged.
• the \\(\text{nh}_3\\) concentration decreases.
• there is not enough information to determine the change in \\(\text{nh}_3\\) concentration.

Explanation:

Identify the chemical system and disturbance

Using the Chemical Equilibrium knowledge point

$$ \text{NH}_3(g) + \text{H}_2\text{S}(g) ightleftharpoons \text{NH}_4\text{HS}(s) $$

The disturbance is: "Additional hydrogen sulfide gas is added to the system."

Apply Le Chatelier's principle

We analyze the effect of adding a reactant gas to the equilibrium mixture.

• Adding \(\text{H}_2\text{S}(g)\) increases its concentration.
• The system shifts to consume the added reactant.
• The forward reaction is favored to reduce \(\text{H}_2\text{S}\).

Determine the change in ammonia concentration

We determine how the shift affects the other reactant, \(\text{NH}_3\).

• The forward reaction consumes both \(\text{NH}_3(g)\) and \(\text{H}_2\text{S}(g)\).
• Therefore, the concentration of \(\text{NH}_3\) must decrease.

Answer:

• The \(\text{NH}_3\) concentration increases.
• The \(\text{NH}_3\) concentration remains unchanged.
• The \(\text{NH}_3\) concentration decreases. (Correct answer)
• There is not enough information to determine the change in \(\text{NH}_3\) concentration.