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IChO 2014-46 International Chemistry Olympiad Practical & Theoretical Examination w Answer Sheets Grading $2.72   Add to cart

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IChO 2014-46 International Chemistry Olympiad Practical & Theoretical Examination w Answer Sheets Grading

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International Chemistry Olympiad Problems with Solutions

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46th International Chemistry Olympiad
July 23, 2014
Hanoi, Vietnam


PRACTICAL EXAMINATION




Country:

Name as in passport:

Student Code:

Language:
This booklet contains 25523 characters

, NTT VN-123

GENERAL INTRODUCTION
Safety
• Safety is the most important issue in the laboratory. You are expected to follow the safety
rules given in the IChO regulations. Safety glasses and lab coats must be worn in
laboratory ALL TIMES.
• If you behave in an unsafe manner, you will receive one warning before you are asked to
leave the laboratory. If required to leave due to a second warning, you will receive a score
of zero for the rest practical examination.
• Eating, drinking, or smoking in the laboratory or tasting a chemical is strictly
forbidden.
• Pipetting by mouth is strictly forbidden.
• Use the labeled waste containers near you for disposal of liquids and solids. A waste
container (plastic can) is also available on each bench for organic and inorganic waste.
Discard used glass capillaries into a solid trash.
• In case of emergency, follow the instructions given by the lab assistants.
Examination Procedures
• This practical examination has 28 pages for 3 practical problems. Periodic Table of
Elements is at the end of this booklet. Do not attempt to separate the sheets.
• You have 5 hours to complete practical problems 1, 2, and 3. You have 30 min to read
through the problems before the START command is given.
• DO NOT begin working on the tasks until the START command is given.
• When the STOP command is given, you must stop your work on the tasks immediately.
A delay in doing so may lead to your disqualification from the examination.
• After the STOP command has been given, wait in your lab space. A supervisor will
check your lab space. The following items should be left behind:
o The practical examination booklet (this booklet),
o Your chosen TLC plates in Petri dish with your student code (Problem 2).
• Do not leave the laboratory until you are instructed to do so by the lab assistants.
• You may need to reuse some glassware during the examination. If this is the case, clean it
carefully in the sink closest to you.
• Replacement of chemicals and laboratory ware will be provided if necessary. Other
than the first, for which you will be pardoned, each such incident will result in the loss of
1 point from your 40 practical points. Refilling of wash-bottle water is permitted with no
loss of points.

Notes
• Use only the pen provided for filling in the answer boxes. You may also use the
calculator and the ruler provided. Do not use the mechanical pencil for filling in the
answer boxes.
• All results must be written in the appropriate areas with the working shown. Results
written elsewhere will not be graded. If you need to do rough calculations, etc., use the


The 46th IChO – Practical Examination. Official English version 2/28

, NTT VN-123

draft papers or the back of the sheets. All answers on the draft papers or the back of the
sheets will NOT be graded.
• You should take care to report answers to an appropriate number of significant figures and
give the appropriate unit.
• Contact a supervisor near you if you need a refreshment/toilet break.
• Read the whole description of the problems before you begin
• An official English version of this examination is available upon request if you require
clarification.

Attention: Pipetting by mouth is strictly Instructions for using the thermometer
forbidden. Student was provided a pipette
1. Press the [ON/OFF] button to display the
bulb. Make sure that you properly use the
pipette bulb shown in Figure below. temperature reading in Celsius.
2. Insert the stainless steel probe (at least 5
cm) in the solution to be measured.
3. Wait for display to stabilize (display value
is unchanged and stable for 3 seconds) and
read the temperature on the display.
4. Press the [ON/OFF] button again to turn
the thermometer off, then rinse the stainless
steel probe with distilled water.




Description of three-way pipette bulb.

An adapter is provided for larger pipettes.




The 46th IChO – Practical Examination. Official English version 3/28

, NTT VN-123

List of chemicals

The concentration indicated on the label is approximate. The exact values are indicated in the table.
Chemical/Reagent Quantity Placed in Labeled Safety
Practical Problem 1
0.100 M KI solution 120 mL Glass bottle 0.1 M KI H320
Solution #A1 contains KI,
H314, H302,
Na2S2O3, and starch indicator in 40 mL Glass bottle Solution #A1
H315, H319
distilled water
Solution #B1 contains Fe(NO3)3, H314, H315,
40 mL Glass bottle Solution #B1
HNO3 in distilled water H319, H335
Solution #A2-1 contains 5.883
×10–4 M Na2S2O3, KNO3, and 360 mL Glass bottle Solution #A2-1 H314 H272
starch indicator in distilled water
Solution #B2 contains 0.1020 M
H314, H272,
Fe(NO3)3 and HNO3 in distilled 100 mL Glass bottle Solution #B2
H315, H319
water.
H2O (Practical
Distilled water 1L Glass bottle
Problem 1)
Practical Problem 2
Artemisinin 1.000 g Small bottle Artemisinin
Sodium borohydride, NaBH4 0.53 g Small bottle NaBH4 H301-H311
CH3OH 20 mL Glass bottle Methanol H225, H301
n-Hexane 30 mL Bottle n-Hexane H225
cerium staining reagent for TLC 3-5 mL Bottle Ceri reagent
CH3COOH 1 mL 1.5 mL vial Acetic Acid H226, H314
Ethyl acetate 5 mL Glass bottle Ethyl acetate
Bag of NaCl for salt bath 0.5 kg Ice bath NaCl bag
CaCl2 in drying tube 5-10 g Tube CaCl2 H319
Practical Problem 3
~ 30 wt% H2SO4, solution in
40 mL Bottle ~30 wt% H2SO4 H314
water
1.00×10–2M KMnO4, aqueous
50 mL Bottle ~0.01 M KMnO4, H272, H302,
solution
2.00×10-3M EDTA, aqueous
40 mL Bottle 2.00×10-3 M EDTA H319
solution
pH = 9-10 Buffer aqueous pH = 9-10 Buffer
40 mL Bottle H302 , H319
Solution, NH4Cl + NH3 Solution
~20 wt% NaOH, aqueous
20 mL Plastic bottle ~20 wt% NaOH, H314
solution
~3 M H3PO4, solution in water 15 mL Bottle ~3 M H3PO4 H314
Indicator: ETOO, solid in KCl ca. 0.5 g Plastic bottle ETOO H301




The 46th IChO – Practical Examination. Official English version 4/28

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