chem 116 quiz 5

Question 1

the chemicals used in today’s experiment

Answer 1

0.1 M NaOH and an unknown acid

Question 2

protect yourself by

Answer 2

keeping your goggles on, wear (at least) a short sleeve shirt, long pants, and closed shoes

Question 3

if you spill the chemicals on you,

Answer 3

wash the area thoroughly with tepid water for 15 minutes and let your TA know ASAP

Question 4

titration is a laboratory procedure that

Answer 4

uses the principles of acid-base neutralization and stoichiometry to determine the concentration of the unknown substance in a solution (allow the known to react with the unknown)

Question 5

add the solution in buret to the flask (slowly/quickly) because

Answer 5

slowly; so you will not pass the equivalence point

Question 6

stop when the pH

Answer 6

has leveled out at the high pH (around 12)

Question 7

titration curve

Answer 7

a plot of the pH of the solution during a titration

Question 8

the equivalence point reflects the fact that

Answer 8

the number of moles of the OH- added exactly equals the number of moles of H+ initially in solution

Question 9

the pH changes very (slowly/quickly) around the equivalence point

Answer 9

quickly

Question 10

in the titration, one needs to record the

Answer 10

volume of the base used to reach the equivalence point

Question 11

strong acid strong base

Answer 11

one equivalence point (the curve you’re used to)

Question 12

polyprotic acid and strong base

Answer 12

two equivalence points

Question 13

any titrated solutions may

Answer 13

go down the drain with lots of water

Question 14

polyprotic acids are

Answer 14

specific acids that are capable of losing more than a single proton per molecule in acid-base reactions

Question 15

pH = ?

Answer 15

pKa

Question 16

Ka = ?

Answer 16

10^(-pKa)

Question 17

pKa = ?

Answer 17

-log(Ka)