applying neutralization titrations

Question 1

what cause the most pronounced change in pH at the equivalence point

Answer 1

strong acids
strong bases

Question 2

which acid is widely used for titration of bases and which is seldom used and why

Answer 2

widely used: HCI hydrochloric acid
seldom used: HNO3 nitric acid because of its oxidizing properties

Question 3

true or false:
The second end point is always used for standardization.

Answer 3

true

Question 4

it is available in primary-standard purity

Answer 4

tris-(hydroxymethyl)aminomethane, (HOCH2)3CNH2 aka TRIS of THAM

Question 5

what is the most common base for preparing standard soln

Answer 5

NaOH

Question 6

what are the other base for preparing standard soln

Answer 6

KOH and Ba(OH)2

Question 7

true or false:
NaOH, KOH and Ba(OH)2 are obtainable in pri-standard purity

Answer 7

false - not obtainable

Question 8

what happens if NaOH is stored in glass bottles

Answer 8

the conc. will decrease slowly (.1 to .3% per week)

Question 9

how to eliminate gas in distilled water when preparing standard base solution

Answer 9

boiled briefly. the water is then allowed to cool bcs hot alkali soln. rapidly absorbs CO2

Question 10

it is a nonhygroscopic crystalline

Answer 10

Potassium Hydrogen Phthalate, KHC8H4O4

Question 11

what is the other pri standard for bases

Answer 11

benzoic acid (obtainable in pri standard purity)
potassium hydrogen iodate

Question 12

it is the most common method for determining organic nitrogen

Answer 12

kjeldahl method

Question 13

protein contain approx. the same percentage of ____

Answer 13

nitrogen

Question 14

since most proteins contain approximately the same percentage of nitrogen, multiplication of this percentage by a suitable factor
meats -
dairy products -
cereals -

Answer 14

meats - 6.25
dairy products - 6.38
cereals - 5.70

Question 15

what methods uses spectrophotometry

Answer 15

Biuret and Lowry methods

Question 16

true or false:
Lowry method can be readily automated

Answer 16

false - biuret method

Question 17

true or false:
the biuret method and the Lowry method are faster

Answer 17

true

Question 18

this method is when the sample is mixed with powdered copper(II) oxide and ignited in a combustion tube to give carbon dioxide, water, nitrogen, and small amounts of nitrogen oxides

Answer 18

dumas method

Question 19

the newest method for determining organic nitrogen involves ____ the sample at ____ for a ____ minutes to convert the nitrogen to ____

Answer 19

combustion
1100 degree Celsius
few
nitrogen oxide

Question 20

what reaction in the determining organic nitrogen gives off visible radiation

Answer 20

chemiluminescence

Question 21

it is an organic and biological materials is conveniently determined by burning the sample in a stream of oxygen.

Answer 21

sulfur