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Part 1: preparation of alum/quantative analysis (calculation of % yield)

1.     Cut a 5cm x 5cm square piece of aluminum from a scrap aluminum can and sand the paint off using steel wool. 

2.     Cut this piece into smaller pieces (about 0.5 cm long) and weigh out ~1g. Record the weight to 3 decimal places.

3.     Place the aluminum in a 400-mL beaker and add 50 mL of 4 M KOH.

4.     Place beaker on the heating mantle and heat gently.

CAUTION - H 2 size 12{H rSub { size 8{2} } } {} GAS (VERY EXPLOSIVE) IS PRODUCED.ENSURE THAT YOU ONLY HEAT THE BOTTOM OF THE BEAKER AND DO NOT LET THE FLAMES GET NEAR THE TOP.

5.     When the bubbles have stopped, remove from the heat, i.e., hydrogen is no longer evolved.

6.     Vacuum filter the solution and save the filtrate, you may toss out the solid. (Ask your TA if you need instruction in performing a vacuum filtration.)

7.     Carefully rinse your graduated cylinder, pour out 25-30 mL of 9 M H 2 SO 4 size 12{H rSub { size 8{2} } ital "SO" rSub { size 8{4} } } {} and then add slowly to the filtrate.

CAUTION - H 2 SO 4 size 12{H rSub { size 8{2} } ital "SO" rSub { size 8{4} } } {} IS A STRONG ACID AND DEHYDRATOR. SEE TA IMMEDIATELY IF YOU SPILL ANY!

8.     Heat gently while stirring until the solution becomes clear. Boil the solution down to a volume of about 45 mL.

7.     While the solution is boiling, prepare an ice bath by filling a bowl half-way with ice and then adding water until the bowl is three-quarters full.

8.     After the "boiling off", let the beaker cool to room temperature and then place it in the ice bath. Crystals of alum should form. Allow to cool for 15 minutes.

9.     After 15 minutes, vacuum filter the product and wash with 10 mL of ethanol.

10. Allow to dry for a few minutes. Dry completely in the microwave at less than 50% power in 10 sec intervals until the weight no longer changes.

11. Calculate the percent yield and describe the appearance of the crystals.

Part 2: qualitative analysis of alum

1.     Use a straw spatula to transfer a few of the alum crystals (about 5 mg) to a watch glass. Add 3 drops of water to the crystals. Stir gently until the crystals dissolve.

2.     Use a small piece of indicator paper to see whether the solution is acidic, basic, or neutral.

3.     Now add 1 drop of 0.5 M BaCl 2 size 12{ ital "BaCl" rSub { size 8{2} } } {} (barium chloride) to the solution. Record your observations.

4.     A really good test for the presence of potassium is a flame test. Using the hot grips, hold a stainless spatula in the flame of a Bunsen burner to volatilize impurities from the spatula.

5.     When one end of the spatula is red hot, remove it, and quickly touch it to a small cluster of crystals. Several should stick.

6.     Slowly bring the spatula (plus crystals) toward the flame and watch carefully. Hold the crystals in the flame for at least 5 seconds (until the solid glows). Record your observations.

7.     Remove the spatula and place on a non-asbestos mat.

Part 3: acid-base properties of aluminum compounds

Clean 3 test-tubes and label them.

Tube 1:

Place 10 drops of 1M aluminum nitrate solution and 2 drops of 6.0 M sodium hydroxide solution, mix well and record your observations on your lab report Then add more sodium hydroxide solution to tube 1 until a reaction is observed (around 7 drops). Mix well. Record your observations.

Tube 2

Place 10 drops of 1M aluminum nitrate solution and 2 drops of 6.0 M sodium hydroxide solution, mix well and record your observations on your lab report Then add 4 mL of 6M HCl and record your observations.

Tube 3

Add 3 mL of 6M ammonium hydroxide, i.e aqueous ammonia to your alum and record your observations.

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, General chemistry lab spring. OpenStax CNX. Apr 03, 2009 Download for free at http://cnx.org/content/col10506/1.56
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