Determine the percent ionization of a 0.215 m solution of benzoic acid.

Explanation:

The percent ionization of a weak acid is the percent of the original acid that ionizes.

You may calculate the percent ionization of an acid of known concentration, from the equilibrium constant.

So, to determine the percent ionization of a 0.215 M solution of benzoic acid, you must look for the equilibrium (dissociation or ionization) constant.

Equilibrium constants depend on temperature. So, you must know the temperature.

For this question, I will assume 25°C, for which you can find that the dissociation constant, Ka, for benzoic acid is 6.25×10⁻⁵.

With that, you follow these steps:

1. Write the ionization equation:

2. Calculate the concentration of the ion C₆H₅CO₂⁻ at equilibrium

                    C₆H₅CO₂H ⇄ C₆H₅CO₂⁻ + H⁺

       I           0.215                  0              0

      C            - x                   + x           + x

      E          0.215 - x              x              x

        Ka = x² / 0.215 - x =  6.25×10⁻⁵

           x² = 0.215 × 6.25×10⁻⁵ = 0.0000078125

           x = 0.00367 M

           If you do not make the assumption but solve the quadratic equation you will get x = 0.00363 M

3. Calculate the percent ionization:

With x = 0.00363 M (exact calculation)

With x = 0.00367 M

i'm pretty sure it is letter c.) car

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.