CHEM 1A03 Chapter Unit 7 Module 2: Chemistry Unit 7- Module 2 – Acid-Base Chemistry II

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Chemistry unit 7: module 2 acid-base chemistry ii. A quantitative measure of the strength of an acid in solution. A quantitative measure of the strength of a base in solution. If we add the 2 reactions together, the total reaction would be 2 waters react to form h3o+ and oh- so the net equilibrium expression would simply be the concentration of h3o+ multiplied by the concentration of oh- When we add the two reactions together, we need to multiply the equilibrium constants together. If we take the negative log of both sides we get this expression: Log10(kw) = -log10(ka) + (-log10(kb)) pka & pkb relationship. A(cid:374)other (cid:449)ay of sayi(cid:374)g (cid:374)egati(cid:448)e log is usi(cid:374)g (cid:862)p(cid:863: pkw is pka plus pkb for a conjugate acid-base pair. Pkw is always equal to 14 at 25 degrees celcius. If we have ka and need kb, you can also use the relationship kw = ka x kb (avoids converting to pka and pkb)

Related Questions

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

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.)

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CHEM 1A03 Chapter Unit 7 Module 2: Chemistry Unit 7- Module 2 – Acid-Base Chemistry II

CHEM 1A03 Full Course Notes

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