What is the value for K_c for the following reaction:
PbCl₂(s) ⇌ Pb²⁺(aq) + 2 Cl^-(aq) ,
If PbCl₂(s) = 1.50 grams,[Pb²⁺] = 1.6 × 10^-2 M and [Cl^-] = 3.2 × 10^-2 M at equilibrium? (The molar mass of PbCl₂(s) is 278 g/mol and its density is 5.85 g/cm³. )

Question

Quizplus · Accepted Answer

To find the value of KS1U1B1cS1U1B0, we need the concentrations of the reactants and products at equilibrium. We can use the given equilibrium concentrations and stoichiometry to calculate the equilibrium concentration of PbClS1U1B12S1U1B0(s):

[PbClS1U1B12S1U1B0]eq = (1.6 × 10S1U1P1-2S1S1P0) (2) (3.2 × 10S1U1P1-2S1S1P0)
                      = 1.024 × 10S1U1P1-5S1S1P0

We can use the mass and density of PbClS1U1B12S1U1B0(s) to convert this to a molar concentration:

[PbClS1U1B12S1U1B0]eq = (1.50 g) / (278 g/mol) / (5.85 g/cmS1U1P13S1S1P0)
                      = 9.00 × 10S1U1P1-4S1S1P0 M

Now we can use the equilibrium concentrations and the stoichiometry to calculate KS1U1B1cS1U1B0:

KS1U1B1cS1U1B0 = ([PbS1U1P12+S1S1P0] eq) ([ClS1U1P1-S1S1P0] eq)S1U1B1 / ([PbClS1U1B12S1U1B0] eq)S1U1B2
               = (1.6 × 10S1U1P1-2S1S1P0) (3.2 × 10S1U1P1-2S1S1P0)S1U1B1 / (9.00 × 10S1U1P1-4S1S1P0)S1U1B2
               = 1.6 × 10S1U1P1-5S1S1P0

Therefore, the answer is B: 1.6 × 10S1U1P1-5S1S1P0.

What Is the Value for Kc for the Following Reaction

What Is the Value for K_c for the Following Reaction