If the prepared solution was made with 4.00 × 10⁻⁴ M lithium fluoride and 4.00 × 10⁻⁴ M of zinc chloride, evaluate the reaction quotient, Q, for zinc fluoride at these values.

Answer 1

The reaction between lithium fluoride and zinc chloride can be represented as follows:

LiF (aq) + ZnCl₂ (aq) → ZnF₂ (s) + 2LiCl (aq)

The reaction quotient Q is the ratio of the product concentrations to the reactant concentrations, with each concentration raised to its stoichiometric coefficient in the balanced chemical equation. Since zinc fluoride is a solid and therefore has a constant concentration, its concentration is not included in the Q expression.

Thus, the Q expression for this reaction is:

Q = [LiCl]² / ([LiF][ZnCl₂])

At the given concentrations of 4.00 × 10⁻⁴ M for both LiF and ZnCl₂, we can substitute these values into the Q expression to obtain:

Q = ([LiCl]²) / ([LiF][ZnCl₂]) Q = [(2 × 4.00 × 10⁻⁴)²] / [(4.00 × 10⁻⁴)(4.00 × 10⁻⁴)] Q = 4.00

Therefore, the reaction quotient Q for the formation of zinc fluoride at these concentrations is 4.00.

Since Q > 1, the reaction is not at equilibrium and the reaction proceeds in the reverse direction to reduce the value of Q.