Math Problem Statement

At 25°C, 0.138 mg AgBr dissolves in 10.0 L of water. What is the equilibrium constant for the reaction below? AgBr(s) ⇌ Ag+(aq) + Br−(aq)

Solution

To find the equilibrium constant (KspK_{\text{sp}}) for the dissolution of AgBr, we use the solubility product constant expression:

AgBr (s)Ag+(aq)+Br(aq)\text{AgBr (s)} \leftrightarrow \text{Ag}^+ (\text{aq}) + \text{Br}^- (\text{aq})

Given dataTo find the equilibrium constant (KspK_{\text{sp}}) for the dissolution of AgBr, we use the solubility product constant expression:

AgBr (s)Ag+(aq)+Br(aq)\text{AgBr (s)} \leftrightarrow \text{Ag}^+ (\text{aq}) + \text{Br}^- (\text{aq})

Given

  • The solubility of AgBr is 0.138 mg in 10.0 L of water.
  • Molar mass of AgBr is approximately 187.77 g/mol.

Step 1: Convert solubility to molarity

First, convert the mass from mg to grams: 0.138 mg=0.138×103 g=0.000138 g0.138 \text{ mg} = 0.138 \times 10^{-3} \text{ g} = 0.000138 \text{ g}

Now, convert this mass to moles using the molar mass: Moles of AgBr=0.000138 g187.77 g/mol7.35×107 mol\text{Moles of AgBr} = \frac{0.000138 \text{ g}}{187.77 \text{ g/mol}} \approx 7.35 \times 10^{-7} \text{ mol}

Since this amount is dissolved in 10.0 L of water, the molarity ([Ag+]=[Br][ \text{Ag}^+ ] = [ \text{Br}^- ]) is: Molarity=7.35×107 mol10.0 L=7.35×108 M\text{Molarity} = \frac{7.35 \times 10^{-7} \text{ mol}}{10.0 \text{ L}} = 7.35 \times 10^{-8} \text{ M}

Step 2: Calculate the equilibrium constant (KspK_{\text{sp}})

The solubility product constant is given by: [ K_{\text{sp}} = [ \text{Ag}^+ ][ \text{Br}^- ] = (7.35 \times 10^{-8})(7.35 \times 10^{-8}) = 5.40 \times 10^{-15} ]

Thus, the equilibrium constant for the dissolution of AgBr is approximately 5.40×10155.40 \times 10^{-15}.

Would you like further details or have any questions?

Here are some related questions:

  1. How would increasing the volume of water affect the solubility of AgBr?
  2. What is the effect of adding common ions like Ag+ or Br- to the solution?
  3. How can the solubility of AgBr change with temperature?
  4. What is the relationship between Ksp and the Gibbs free energy for a dissolution process?
  5. How does the ionic strength of a solution affect the activity coefficients in the calculation of Ksp?

Tip: The solubility product constant (Ksp) can be used to predict whether a precipitate will form when two solutions are mixed.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Solubility product constant (Ksp)
Stoichiometry
Unit conversion

Formulas

Ksp = [Ag+][Br−]
Molarity = moles / volume
Moles = mass / molar mass

Theorems

Solubility product constant (Ksp) theorem

Suitable Grade Level

High School (Grades 10-12)