What is the objective of this experiment in a few sentences? PART C & D (couldn't post picture) c. Acid HydrolysisIn a small erlenmeyer flask place 25 mL of the stock starch solution and 5 mL of 10%HCI and mix. Place in boiling water bath. After 30 minutes of heating, use a plasticpipette to withdraw a few drops (aliquot) and place them on a spot plate. Allow to coolfor a few seconds and add 2 drops of iodine solution. Observe color and interpret theresults.Withdraw and test an aliquot every 5 minutes until the test with iodine does not produce ablue color. Keep track of the total elapsed time. Interpret the results. Do not discardsample and proceed to part d.d. Fehlings Test on hydrolyzed sampleUpon completing part c. above and the test no longer gives a blue color, withdraw a 5 mLsample and neutralize with 10% NaOH until no longer acidic to litmus. Add 1 mL ofFehlings solution (A+B), place in boiling water bath, and time any color change asbefore. Compare this result with your result from part b. above. Interpret your results. 900baso PROCEDURE:RE:PART II: HYDROLYSISStarch and cellulose are both polymers of D-glucose. In starch, the glucose units are joinedby a-acetal linkages and in cellulose by ß-acetal linkages. In this experiment starch will betreated with iodine solution (a color test for starch) and with Fehlings solution (a test for freealedehyde). Starch is later subjected to hydrolysis in an acidic solution and subsequentlytested with iodine and Fehlings solutions.28LAYheouldmuse44Prepare a stock starch solution by adding 2.0 g of starch to 100 mL of water and stir for about5 minutes in order to dissolve as much starch as possible. Allow any undissolved starch tode settle to the bottom and use the saturated solution. Then proceed as follows...10Toggla. Iodine Test mil bas died stew gailiod ni soslq (8+A) noalPlace 5 mL of stock solution into a 6" test tube. Add 2 drops of dilute iodine solution.UstObserve the blue color produced. This sensitive diagnostic test for starch is produced byDiodine molecules trapped in the spiral coils of the linear starch molecules. CheampaNow place the test tube in the boiling water bath and note the loss of the blue color.This occurs because the increased molecular motion of the starch molecules allows thetrapped iodine molecules to escape. Cool the test tube under cold running water and notethe return of the blue color.b. Fehlings TestBu Place 3 mL of stock starch solution in a 6" test tube and add 1 mL of Fehlings solution (A+ B). Place in boiling water bath and carefully time the color change as before. Comparetime with that given by D-glucose. Stop heating after 10 minutes and interpret the results.dis case, SO||R-C-H +CARBOHYDRATE REACTIONSPART I: OXIDATIONAldehydes are readily oxidized even with such weak oxidizing agents as Cu²+ (FehlingsSolution). Such a reagent can be used to test for the presence or absence of a free aldehydei group in a molecule, including carbohydrates.alay+2Cu¹²alpha-D-GlucoseCH₂OHH HOPROCEDURE:1.On a hot plate, prepare a water bath by heating a 250 mL beaker, half filled with water.2. In a small flask, mix together 10 mL of Fehlings A and 10 mL of Fehlings B solution.Use for the following tests...3. Into each of 4 test tubes (6") add 2 mL (~40 drops) of the Fehlings A and B mixture.Next add 2 mL of 5% solutions of the sugar listed below, one in each test tube. Mix andset in a boiling water bath. As soon as the test tubes are placed in the boiling water bath,time how long it takes for formation of a red brick precipitate. (Times may range from afew seconds to several minutes). If no ppt. forms after 5 min., record your time as >5min. and terminate that particular test. Test the following sugars...beingCH₂OHCH₂OHHO HонOH HOH HH HỌa leveOHOHH OHH OHOH H+ OHHCH₂OHbeta-D-FructoseHmonCH₂OHOHO||R-C-O +HOHCH₂OHOH HSucroseH OHOH HHCu₂0 ppt.LactoseHCH₂OHCH₂OH-онpourbrick redOH HH OH43OH

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Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

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Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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What is the objective of this experiment in a few sentences?

PART C & D (couldn't post picture)

c. Acid Hydrolysis
In a small erlenmeyer flask place 25 mL of the stock starch solution and 5 mL of 10%
HCI and mix. Place in boiling water bath. After 30 minutes of heating, use a plastic
pipette to withdraw a few drops (aliquot) and place them on a spot plate. Allow to cool
for a few seconds and add 2 drops of iodine solution. Observe color and interpret the
results.

Withdraw and test an aliquot every 5 minutes until the test with iodine does not produce a
blue color. Keep track of the total elapsed time. Interpret the results. Do not discard
sample and proceed to part d.

d. Fehlings Test on hydrolyzed sample
Upon completing part c. above and the test no longer gives a blue color, withdraw a 5 mL
sample and neutralize with 10% NaOH until no longer acidic to litmus. Add 1 mL of
Fehlings solution (A+B), place in boiling water bath, and time any color change as
before. Compare this result with your result from part b. above. Interpret your results.

900
baso PROCEDURE:
RE:
PART II: HYDROLYSIS
Starch and cellulose are both polymers of D-glucose. In starch, the glucose units are joined
by a-acetal linkages and in cellulose by ß-acetal linkages. In this experiment starch will be
treated with iodine solution (a color test for starch) and with Fehlings solution (a test for free
aledehyde). Starch is later subjected to hydrolysis in an acidic solution and subsequently
tested with iodine and Fehlings solutions.
28
LA
Yhe
ould
muse
44
Prepare a stock starch solution by adding 2.0 g of starch to 100 mL of water and stir for about
5 minutes in order to dissolve as much starch as possible. Allow any undissolved starch to
de settle to the bottom and use the saturated solution. Then proceed as follows...
10
Toggl
a. Iodine Test mil bas died stew gailiod ni soslq (8+A) no
alPlace 5 mL of stock solution into a 6" test tube. Add 2 drops of dilute iodine solution.
UstObserve the blue color produced. This sensitive diagnostic test for starch is produced by
Diodine molecules trapped in the spiral coils of the linear starch molecules. Che
ampa
Now place the test tube in the boiling water bath and note the loss of the blue color.
This occurs because the increased molecular motion of the starch molecules allows the
trapped iodine molecules to escape. Cool the test tube under cold running water and note
the return of the blue color.
b. Fehlings Test
Bu Place 3 mL of stock starch solution in a 6" test tube and add 1 mL of Fehlings solution (A
+ B). Place in boiling water bath and carefully time the color change as before. Compare
time with that given by D-glucose. Stop heating after 10 minutes and interpret the results.
dis case,

SO
||
R-C-H +
CARBOHYDRATE REACTIONS
PART I: OXIDATION
Aldehydes are readily oxidized even with such weak oxidizing agents as Cu²+ (Fehlings
Solution). Such a reagent can be used to test for the presence or absence of a free aldehyde
i group in a molecule, including carbohydrates.
alay
+2
Cu¹²
alpha-D-Glucose
CH₂OH
H HO
PROCEDURE:
1.
On a hot plate, prepare a water bath by heating a 250 mL beaker, half filled with water.
2. In a small flask, mix together 10 mL of Fehlings A and 10 mL of Fehlings B solution.
Use for the following tests...
3. Into each of 4 test tubes (6") add 2 mL (~40 drops) of the Fehlings A and B mixture.
Next add 2 mL of 5% solutions of the sugar listed below, one in each test tube. Mix and
set in a boiling water bath. As soon as the test tubes are placed in the boiling water bath,
time how long it takes for formation of a red brick precipitate. (Times may range from a
few seconds to several minutes). If no ppt. forms after 5 min., record your time as >5
min. and terminate that particular test. Test the following sugars...
being
CH₂OH
CH₂OH
H
O H
он
OH H
OH H
H HỌ
a leve
OH
OH
H OH
H OH
OH H
+ OH
H
CH₂OH
beta-D-Fructose
H
mon
CH₂OH
OH
O
||
R-C-O +
HO
H
CH₂OH
OH H
Sucrose
H OH
OH H
H
Cu₂0 ppt.
Lactose
H
CH₂OH
CH₂OH
-он
pour
brick red
OH H
H OH
43
OH

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