IV. Procedure Cut an approximate 5 cm. square of aluminum from an aluminum can,
ID: 543126 • Letter: I
Question
IV. Procedure Cut an approximate 5 cm. square of aluminum from an aluminum can, and beaker must be clamped screen ring scour only the painted outside of it with coarse steel wool to scrape off all paint. Cleaning the aluminum well now, right down to the shiny metal, will avoid problems later on. The plastic coating on the inside will easily come off in one piece if you do not scour it at all. Find and record the exact mass, to 0.001 g, of the piece of aluminum; it should weigh about 0.5 gram. support Figure &-1 Add the weighed aluminum to a 250 mL beaker, then clamp the beaker down onto a wire sereen over a ring at your bench. Next, add 50 mL of 2 M potassium hydroxide, KOH to the beaker. (Caution: strong base is quite caustic and will eat holes in clothing and in you! Do not spatter!) Use a small Bunsen burner to heat gently with a small flame. Unstable set-ups will not be tolerated, and a wire screen is absolutely necessary to prevent the beaker from spot heating and cracking. Turn on the lab's hoods and fans, and open windows. Gently boil until the liquid is concentrated to one-half its original level. Do NOT e more because spattering can occur. If the level drops below this, simply add more water to bring the level up. If foaming is an issue, you are heating too strongly, and you need to lower the heat source or pullit further from the beaker. When the plastic king comes off, use tongs to raise the plastic above the hot solution, and rinse it with deionized water. Then place it on paper towels and blot dry; set it aside to dry further. If the solution is not clear and contains suspended solids, filter the hot solution (caution!) through a thin plug of glass wool that is moistened by pouring 2 mL of deionized water through it (Figure 8-2). After filtering, rinse the glass wool with 1 mL or less of DI water to minimize loss of product. After the plastic backing has dried, weigh the plastic and deduct this mass from the original mass of the aluminum piece to get the mass of just the aluminum metal.Explanation / Answer
Procedure:
1)Take one Al can and cut 5cm of Al . After that scour out only painted side and collect Al by cleaning with the help of steel wool.
2)Clean the metal and weigh around 0.5g of Al.
3)Take a 250ml of beaker and add weighed amount of Al with the addition of 50ml of 2M of KOH.
4)Heat gently the system on bunsen flame burner and heat till the whole solution concentrate to half .Do not concentarte more it can cause spattering.
5)In case of over heating foamng can happen to avoid this lower the temperature.
6)When the plastic backing comes off use the tongs to raise the plastic off above the solution and rinsed with Deionised water.and keep it for dry.If the solution is not clear filter the hot solution with the help of glass wool moistened by 2ml of DI water.After that rinse the wool piece with 1ml of DI water to take off product from wool.
7)After getting it dry fully weigh the plastic and deduct from the original mass of Al piece to get the exact mass of Al metal.
8)Cool the solution mixture by stirring and adding 20ml of 9M H2SO4 slowly.Large lumps of aluminium hydroxide will appear and then heat gently the solution untill these lumps gets disappear.If the solution is not clear filter it with wool plug moistened by DI water and keep the clear solution in ice bath for 20-25 mins.scratch the glass wall and bottom with glass rod to facilitate the crystallization.
9)Take the buchner funnel fitted with circular filter paper.Rinse the paper with small amount of water and pour the alum solution slowly in vaccum filter set up.rinse the beaker with 1:1 20ml Ethanol -water solution and pour the solution to filtered crystal ,allow thw vaccum to run untill you get the dry crystal .
10)After getting fukky dried crystals weigh the crystals and Report to Instructor.
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