NH3 + H20 <---> NH4+ + OH-
this is aqueous solution. In 0.0180 M nH3, THE [OH-] is 5.60 X 10^-4 M. it is assumed that the volumes are additive.
Determine the value of the base ionization constant, kb, for NH3.
i am not sure how to approach this problem. i don't udnerstand how to set up the ICE table, because concentrations for both NH3 and OH are given. and i know we cannot use henderson hasalbach equation, so what should i do?
nvm, i get it.
To determine the value of the base ionization constant (Kb) for NH3, you can use the given information about the concentrations of NH3 and OH-. Here's how you can approach the problem:
Step 1: Write the balanced chemical equation for the base ionization of NH3 in water:
NH3 + H2O ⇌ NH4+ + OH-
Step 2: Set up an ICE table to track the changes in concentration:
NH3 + H2O ⇌ NH4+ + OH-
Initial: 0.0180 M 0 M 0 M 0 M
Change: -x -x +x +x
Equilibrium: 0.0180-x -x x x
Step 3: Since it is assumed that the volumes are additive, the concentration of NH3 at equilibrium can be considered to be 0.0180 - x M. From the given information, [OH-] is 5.60 × 10^-4 M. Therefore, [OH-] = x M.
Step 4: Write the expression for the base ionization constant (Kb) using the equilibrium concentrations:
Kb = ([NH4+][OH-]) / [NH3]
Step 5: Substitute the equilibrium concentrations into the Kb expression:
Kb = (x^2) / (0.0180 - x)
Step 6: Plug in the given value of [OH-] into the expression:
5.60 × 10^-4 = (x^2) / (0.0180 - x)
Step 7: Solve the equation for x. This can be done by rearranging the equation:
x^2 = 5.60 × 10^-4 × (0.0180 - x)
Expand and rearrange the equation to get it into quadratic form:
x^2 + 5.60 × 10^-4x - 1.008 × 10^-5 = 0
Step 8: Solve the quadratic equation using the quadratic formula or factoring methods:
Using the quadratic formula,
x = (-b ± √(b^2 - 4ac)) / (2a)
a = 1, b = 5.60 × 10^-4, c = -1.008 × 10^-5
Step 9: Once you solve for x, you can substitute its value into the expression for Kb:
Kb = (x^2) / (0.0180 - x)
By following these steps, you can determine the value of the base ionization constant, Kb, for NH3.