Titration Experiment Precision matters — Transcript

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1. 0:00[Music]
2. 0:08titration or acid-base titration that's
3. 0:11the title for the experiment what is
4. 0:13titration is a methodology
5. 0:16is a methodology that is used for
6. 0:19acid-base it's used for oxidation
7. 0:21reduction is used for different type of
8. 0:24reactions but the experiment we are
9. 0:27doing today it's
10. 0:29acid base titration
11. 0:31you have one
12. 0:32known and you have one unknown both of
13. 0:35them you have the name for the compounds
14. 0:38what can what is considered to be your
15. 0:40known solution is the one that you have
16. 0:44the concentration for so if you have the
17. 0:46acid with the concentration or if you
18. 0:48have the acid that you have the mass and
19. 0:50you have the molar mass you can you can
20. 0:53calculate the number of moles
21. 0:55then that is your known sample if you
22. 0:58have either acid or base that needs to
23. 1:00be standardized or needs to be tested in
24. 1:03order to find the concentration that
25. 1:05would count as your
26. 1:07unknown so basically it's what you are
27. 1:10looking for you are looking for
28. 1:12concentration of one
29. 1:14of the either acid or base but you have
30. 1:17to have the other one already
31. 1:20this in this method we are going to use
32. 1:22a buret
33. 1:23with the buret that we are using it's
34. 1:26the
35. 1:28most accurate or one of the most
36. 1:29accurate measuring device for
37. 1:31for the volume and we would sometimes
38. 1:34use pipette we use uh it depends on the
39. 1:37procedure whatever is going to ask
40. 1:39pipette and burns are the most accurate
41. 1:41equipments that we could use in the
42. 1:44in the lab
43. 1:45for the for the titration both of them
44. 1:48are
45. 1:49needed unless you have the
46. 1:52solid
47. 1:53acid or solid base that is a stable like
48. 1:56khp that you are using today and because
49. 1:59it's a stable it would be used as a
50. 2:01primary uh standard so to start
51. 2:05with the part one
52. 2:07uh we are going to prepare the sodium
53. 2:09hydroxide solution and standardize using
54. 2:12khp khp
55. 2:15it's not the potassium and hydrogen and
56. 2:18phosphorus when you are trying to find
57. 2:20that molar mass this is not the
58. 2:24molecular formula for the compound that
59. 2:26is the abbreviation
60. 2:28for the
61. 2:30potassium hydrogen phetalate
62. 2:33the molar mass is given in the lab
63. 2:35manual as a
64. 2:36204.22 grams so do not calculate the
65. 2:40molar mass based on this tree leather
66. 2:42this is the abbreviation for the actual
67. 2:44name for it
68. 2:45it's a stable it doesn't absorb water
69. 2:48so it can be used as a primary standard
70. 2:52in the lab
71. 2:53so we are going to have the acid inside
72. 2:56a um
73. 2:58erlenmeyer flask
74. 2:59the base is going to be inside of buret
75. 3:02then we also are using acid-base
76. 3:06indicator what is acid-base indicator
77. 3:08acid-base indicator is a
78. 3:11weak acid organic weak organic acid or a
79. 3:14weak organic base that has different
80. 3:16color in acidic solution compared to
81. 3:18neutral solution or compared to a basic
82. 3:20solution
83. 3:21so it's going to indicate if our
84. 3:23solution is acidic it's going to
85. 3:25indicate if the solution is based so
86. 3:27that's what we are using for the
87. 3:30end point of the reaction
88. 3:32so that brings definition for endpoint
89. 3:34reaction with his endpoint reaction
90. 3:37endpoint reaction is
91. 3:40a point where you have added enough base
92. 3:44uh to neutralize the acid in a way that
93. 3:48the indicator is going to change color
94. 3:50that would be end point of the reaction
95. 3:52so when the indicator changes color is
96. 3:55end point of the reaction
97. 3:57if you count or calculate number of
98. 4:00moles number of moles of the acid with
99. 4:02equals number of moles of base at that
100. 4:04point you have equivalence point a
101. 4:07coolest point is very important for us
102. 4:09because based on the coolest point or
103. 4:11the volume of the standard used for the
104. 4:15um for the uh titration
105. 4:18or the volume used is going to be um
106. 4:23we start with that volume and then we
107. 4:25have the equation for a
108. 4:28point of equivalence or equivalence
109. 4:30point number of moles of acid equals
110. 4:32number of moles of base according to
111. 4:34balanced equation so if it's a
112. 4:36one-to-one ratio if your acid is a
113. 4:39monoprotic and the base is a monoprotic
114. 4:42base then you are going to have the same
115. 4:45number of moles of acid and base at the
116. 4:48coolest point so you can calculate the
117. 4:51molarity or the concentration for your
118. 4:53acid or the base whichever is the
119. 4:56unknown for you
120. 5:02[Music]