Ch. 16 acid / base **test ** [35 points] Honors Chemistry

Show your work in an organized manner, includes any relevant equation / formula, proper units in your work / answer, and the proper number of significant figures in your answer.

1. What is the pH of ___ ? [10 points]

a. 2.5 mM HCl (a strong acid)

b. 25 µM KOH (a strong base)

2. buffer [10 points]

a. what is a buffer ?

b. what is the composition of a buffer ?

c. how does a buffer work ?

3. weak base problem [15 points]

a. write the algebraic expression for K

_{b}of CH_{3}NH_{2}(methylamine) and the corresponding chemical equation.b. what is the pH of a 5.0 mM methylamine (K

_{b}= 4.4 * 10 -4) aqueous solution ?