CHEM 104 FINAL PAPER COMPLETE
QUESTIONS AND ACCURATE SOLUTIONS
STUDY GUIDE
●● -definition of buffer
-numerical requirement
Answer: -a weak acid and its conjugate base or a weak base and its
conjugate acid that is resistant to changes in pH when reacting with a
strong acid or strong base
-must be in a 10:1 ratio
●● format of buffer equation
Answer: HX + MOH -> H2O + MX
acid . base . water . salt
●● what are the strong acids
Answer: HCl, HBr, HI, HNO3, H2SO4, HClO4
●● 2 ways to find pH if Ka is known
Answer: 1- make ICE table to find H3O+
2- H-H law (pka=-log ka)
, ●● 2 requirement of the H-H law
Answer: 1- ratio must be between .1 and 10
2- the concentration of conj base and conj acid must each exceed Ka by
a factor of 100 or more
●● how to select a buffer-
Answer: acid/base pair with pKa within one pH unit of desired pH
if there are two, pick the higher concentration
●● when to use SCF table
Answer: used when adding a strong base or strong acid
●● what does pka mean
Answer: take the negative log
●● how does increasing or decreasing concentration effect the
effectiveness of the buffer?
Answer: higher concentration of the buffer, the better the buffering
capacity
●● TITRATIONS
Answer:
QUESTIONS AND ACCURATE SOLUTIONS
STUDY GUIDE
●● -definition of buffer
-numerical requirement
Answer: -a weak acid and its conjugate base or a weak base and its
conjugate acid that is resistant to changes in pH when reacting with a
strong acid or strong base
-must be in a 10:1 ratio
●● format of buffer equation
Answer: HX + MOH -> H2O + MX
acid . base . water . salt
●● what are the strong acids
Answer: HCl, HBr, HI, HNO3, H2SO4, HClO4
●● 2 ways to find pH if Ka is known
Answer: 1- make ICE table to find H3O+
2- H-H law (pka=-log ka)
, ●● 2 requirement of the H-H law
Answer: 1- ratio must be between .1 and 10
2- the concentration of conj base and conj acid must each exceed Ka by
a factor of 100 or more
●● how to select a buffer-
Answer: acid/base pair with pKa within one pH unit of desired pH
if there are two, pick the higher concentration
●● when to use SCF table
Answer: used when adding a strong base or strong acid
●● what does pka mean
Answer: take the negative log
●● how does increasing or decreasing concentration effect the
effectiveness of the buffer?
Answer: higher concentration of the buffer, the better the buffering
capacity
●● TITRATIONS
Answer:
