CHEM 134 Lecture Notes - Lecture 14: Rice Chart, Ionic Compound, Hydrolysis

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lavenderfish582

7 Feb 2018

School

University of Maryland

Department

Chemistry and Biochemistry

Course

CHEM 134

Professor

Jason Kahn

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Document Summary

It"s all because of gibbs free energy. No acid stronger than h3o+ and no base stronger than oh can exist in aqueous solution, leading to the phenomenon known as the leveling effect. Any species that is a stronger acid than the conjugate acid of water (h3o+) is leveled to the strength of h3o+ in aqueous solution because h3o+ is the strongest acid that can exist in equilibrium with water. In aqueous solution, any base stronger than oh is leveled to the strength of. Oh because oh is the strongest base that can exist in equilibrium with water. Any substance whose anion is the conjugate base of a compound that is a weaker acid than water is a strong base that reacts quantitatively with water to form hydroxide ion. Ionization constants for weak monoprotic acids and bases. Strong acids and bases ionize essentially completely in water; the percent ionization is always approximately 100%, regardless of the concentration.

Related Questions

For conjugate acid-base pairs, how are Ka and Kb related?

Consider the reaction of acetic acid in water:

CH₃CO₂H (aq) + H₂O (l) ⇌ CH₃CO₂⁻ (aq) + H₃O⁺ (aq) where Ka = 1.8 × 10⁻⁵

Which two bases are competing for the proton?
Which is the stronger base?
In light of your answer to part b. why do we classify the acetate ion (CH₃CO₂⁻) as a weak base? Use an appropriate reaction to justify your answer.
In general, as base strength increases, conjugate acid strength decreases. Explain why the conjugate acid of the weak base NH₃ is a weak acid.

To summarize, the conjugate base of a weak acid is a weak base and the conjugate acid of a weak base is a weak acid (weak gives you weak). Assuming Ka for a monoprotic strong acid is 1× 10⁶, calculate Kb for the conjugate base of this strong acid.

Why do conjugate bases of strong acids have no basic properties in the water?

List the conjugate bases of the six common strong acids.

To tie it all together, some instructors have students think of Li⁺, K⁺, Rb⁺, Cs⁺, Ca²⁺, Sr²⁺, and Ba²⁺ as the conjugate acids of the strong bases LiOH, KOH, RbOH, CsOH, Ca(OH)₂, Sr(OH)₂, and Ba(OH)₂. Although not technically correct, the conjugate acid strength of these cations is similar to the conjugate base strength of the strong acids. That is, these cations have no acidic properties in water; similarly, the conjugate bases of strong acids have no basic properties (strong gives you worthless). Fill in the blanks with the correct response. The conjugate base of a weak acid is a_____base. The conjugate acid of a weak base is a_____acid. The conjugate base of a strong acid is a_____base. The conjugate acid of a strong base is a_____ acid. ( Hint: Weak gives you weak and strong gives you worthless.)

periwinklegoat463

For conjugate acid-base pairs, how are K_a and K_b related?

Consider the reaction of acetic acid in water.

where

a. Which two bases are competing for the proton?

b. Which is the stronger base?

c. In light of your answer to part b, why do we classify the acetate ion (CH₃CO₂^-) as a weak base? Use an appropriate reaction to justify your answer.

In general, as base strength increases, conjugate acid strength decreases. Explain why the conjugate acid of the weak base NH₃ is a weak acid.

To summarize, the conjugate base of a weak acid is a weak base and the conjugate acid of a weak base is a weak acid (weak gives you weak). Assuming K_a for a monoprotic strong acid is 1x10⁶, calculate K_b for the conjugate base of this strong acid. Why do conjugate bases of strong acids have no basic properties in water? List the conjugate bases of the six common strong acids. To tie it all together, some instructors have students think of Li⁺, K⁺, Rb⁺, Cs⁺, Ca²⁺, Sr²⁺, and Ba²⁺ as the conjugate acids of the strong bases LiOH, KOH, RbOH, CsOH, Ca(OH)₂, Sr(OH)₂, and Ba(OH)₂. Although not technically correct, the conjugate acid strength of these cations is similar to the conjugate base strength of the strong acids. That is, these cations have no acid properties in water; similarly, the conjugate bases of strong acids have no basic properties (strong gives you worthless). Fill in the blanks with the correct response. The conjugate base of a weak acid is a ______ base. The conjugate acid of a weak base is a ______ acid. The conjugate base of a strong acid is a ______ base. The conjugate acid of a strong base is a ______ acid. (Hint: Weak gives you weak and strong gives you worthless.)

limeswan13

Decide if the following statements are true or false.

True False The weaker the acid, the stronger the conjugate base.

True False The K_a equilibrium constant always refers to the reaction of an acid with water to produce the conjugate base of the acid and the hydronium ion.

True False Strong acids are assumed 100% dissociated in water.

True False The conjugate base of a weak acid is a strong base.

True False As a solution becomes more basic, the pOH of the solution increases.

True False As the K_b value for a base increases, base strength increases.

CHEM 134 Lecture Notes - Lecture 14: Rice Chart, Ionic Compound, Hydrolysis

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