real world project: determination of vitamin c in fruit juices brian gillease and lauren burns
TRANSCRIPT
Objective
• Calculate vitamin C in a Vitamin C tablet• Titrate fruit juices• Calculate amount of vitamin C in each juice• Compare juices to tablet
Importance
• Vitamin C –– antioxidant; binds with carbon, hydrogen, oxygen;
oxidizes easily– Safe and efficient nutrient, helps protect body
against cardiovascular disease, eye disease, and other diseases
Procedures - Errors
• Juicer – too much pulp
• Filtration – pulp too thick
• Strawberry Juice – red color of juice
Clementine Juice
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 + starch indicator
TrialMass KI
(g)
Initial Vol. Na2S2O3
(mL)
Final Vol. Na2S2O3
(mL)
Vol. Na2S2O3
AddedConsumed Moles I3-
Moles I3- Present
Grams Ascorbic
Acid % Difference
1 2.0013 0 26 260.0011110
920.0002935
740.0517059
62 70.62161244
2 2.0009 0 28.1 28.10.0012008
340.0002038
320.0359000
91 79.60222108
3 2.0022 0 29.5 29.50.0012606
620.0001440
040.0253628
43 85.5892935
Moles I3- Formed
0.001404666 Average
0.037656299 78.60437568
Manufacturer's Claim 0.176
grams per fruit
Data
Clementine Juice Spike
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 +
starch indicator
TrialMass KI (g)
Mass AA (g)
Total Mass AA (g)
Initial Vol. Na2S2O3
(mL)
Final Vol.
Na2S2O3 (mL)
Vol. Na2S2O3
Added
Consumed Moles
I3-
Moles I3-
Present
Grams Ascorbic
Acid%
Difference
1 2.00560.003
10.020
7 0 22 220.001574
384
-0.00016
9717
-0.0298915
87244.403800
1
2 2.0150.003
4 0.021 0 18.5 18.50.001323
9148.07527
E-050.0142226
1832.2732466
8
3 2.00150.004
20.021
8 0 20.25 20.250.001449
149
-4.44824
E-05
-0.0078344
84135.938000
9
Moles I3- Formed
0.001404666 Average
-0.0078344
84137.538349
2
Manufacturer's Claim 0.0176
Papaya Juice
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 + starch indicator
TrialMass KI
(g)
Initial Vol. Na2S2O3
(mL)
Final Vol. Na2S2O3
(mL)
Vol. Na2S2O3
AddedConsumed Moles I3-
Moles I3- Present
Grams Ascorbic
Acid%
Difference
1 2.0009 0 22.2 22.20.00094870
20.00045596
50.08030706
2100.097215
1
2 2.0022 0 21.4 21.40.00091451
40.00049015
20.08632834
7 93.7988006
3 2.0014 0 23.2 23.20.00099143
6 0.000413230.07278045
7107.970233
2
Moles I3- Formed
0.001404666 Average
0.079805289
16.52166457
Manufacturer's Claim 0.0956
grams per fruit
Papaya Juice Spike
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 + starch
indicator
TrialMass KI (g)
Mass AA (g)
Total Mass AA (g)
Initial Vol.
Na2S2O3
(mL)
Final Vol. Na2S2O3
(mL)
Vol. Na2S2O3 Added
Consumed Moles I3-
Moles I3- Present
Grams Ascorbic
Acid
% Differenc
e
1 2.0021 0.0029 0.0985 0 20 200.0014312
58
-2.65916E
-05
-0.004683
47104.7547
914
2 2.009 0.0032 0.0988 0 18.2 18.20.0013024
450.000102
2220.018003
83681.77749
418
3 2.0029 0.0036 0.0992 0 19.3 19.30.0013811
642.35024E
-050.004139
37195.82724
659
Moles I3- Formed
0.001404666 Average
0.005819913
94.11984407
Manufacturer's Claim 0.0956
Orange Juice
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 + starch indicator
Trial Mass KI (g)
Initial Vol. Na2S2O3
(mL)
Final Vol. Na2S2O3
(mL)
Vol. Na2S2O3
AddedConsumed Moles I3-
Moles I3- Present
Grams Ascorbic
Acid%
Difference
1 2.005 0 31.1 31.10.00132903
77.56294E-
050.01332027
573.9329258
3
2 2.0067 0 30.3 30.30.00129484
90.00010981
70.01934155
962.1495906
7
3 2.0039 0 30 300.00128202
90.00012263
70.02159954
157.7308399
9
Moles I3- Formed
0.001404666 Average
0.018087125
64.60445217
Manufacturer's Claim 0.0511
grams per fruit
Orange Juice Spike
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 + starch
indicator
TrialMass KI (g)
Mass AA (g)
Total Mass AA (g)
Initial Vol.
Na2S2O3 (mL)
Final Vol. Na2S2O3 (mL)
Vol. Na2S2O3 Added
Consumed
Moles I3-
Moles I3-
Present
Grams Ascorbic
Acid
% Differenc
e
1 2.0105 0.004 0.0551 0 21 210.00150
2821
-9.81545
E-05
-0.01728
7528131.374
8241
2 2.0008 0.0039 0.055 0 19.35 19.350.00138
47421.99242
E-050.00350
916893.6196
9371
3 2.0065 0.0037 0.0548 0 18.55 18.550.00132
74927.71746
E-050.01359
241575.1963
225
Moles I3- Formed
0.001404666 Average
-6.19815
E-05100.063
6134
Manufacturer's Claim 0.0511
Grapefruit Juice
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 + starch indicator
TrialMass KI
(g)
Initial Vol.
Na2S2O3 (mL)
Final Vol. Na2S2O3
(mL)
Vol. Na2S2O3
AddedConsumed Moles I3-
Moles I3- Present
Grams Ascorbic
Acid%
Difference
1 2.0022 0 30.1 30.10.00128630
30.00011836
4 0.0208468845.7112494
2 1.995 0 33.8 33.8 0.00144442-3.97532E-
05-
0.00700156118.233227
9
3 2.0039 0 30.5 30.50.00130339
6 0.000101270.01783623
853.5514632
8
Moles I3- Formed
0.001404666 Average 0.01056052
72.49864685
Manufacturer's Claim 0.0384
grams per fruit
Grapefruit Juice Spike
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 + starch indicator
TrialMass KI
(g)Mass AA
(g)
Total Mass AA
(g)
Initial Vol. Na2S2O3
(mL)
Final Vol. Na2S2O3
(mL)
Vol. Na2S2O3
AddedConsumed Moles I3-
Moles I3- Present
Grams Ascorbic
Acid%
Difference
1 2.0056 0.0037 0.0421 0 19 190.0013596
954.49713E-
050.0079205
8981.186249
55
2 2.015 0.0033 0.0417 0 18.5 18.50.0013239
148.07527E-
050.0142226
1865.893001
92
3 2.0015 0.0037 0.0421 0 19.5 19.50.0013954
779.1898E-
060.0016185
696.155440
19
Moles I3- Formed
0.001404666 Average
0.007920589
81.07823055
Manufacturer's Claim 0.0384
Strawberry Juice
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 + starch indicator
TrialMass KI
(g)
Initial Vol.
Na2S2O3 (mL)
Final Vol. Na2S2O3
(mL)
Vol. Na2S2O3
AddedConsumed Moles I3-
Moles I3- Present
Grams Ascorbic
Acid%
Difference
1 2.0012 0 37 370.0015811
69
-0.0001765
03
-0.0310866
97537.84079
67
2 1.9992 0 28.7 28.70.0012264
750.0001781
920.0313841
28342.02996
76
3 2.0003 0 25.5 25.50.0010897
250.0003149
420.0554692
65681.25725
02
Moles I3- Formed
0.001404666 Average
0.018588899
161.8154737
Manufacturer's Claim 0.0071
grams per fruit
Strawberry Juice Spike
30 mL filtered, digested soln. + 50 mL KIO3 soln. + KI + 10 mL H2SO4 + starch
indicator
TrialMass KI (g)
Mass AA (g)
Total Mass AA
(g)
Initial Vol.
Na2S2O3
(mL)
Final Vol. Na2S2O3
(mL)
Vol. Na2S2O3
Added
Consumed Moles
I3-Moles I3- Present
Grams Ascorbic
Acid
% Differenc
e
1 2.0034 0.0031 0.0102 0 18.4 18.40.001316
7578.7909E-
050.015483
02451.79435
343
2 2.0021 0.0038 0.0109 0 19.1 19.10.001366
8513.7815E-
050.006660
18338.89740
287
3 2.0018 0.0035 0.0106 0 20.2 20.20.001445
571
-4.09042E
-05
-0.007204
281167.9649
177
Moles I3- Formed
0.001404666 Average
0.004979642
86.21889134
Manufacturer's Claim 0.0071