Weigh 40 G Urea, Oxalic Acid

What I have done are Hypotheses paragraph, introduction, conclusion, (not provided this time) and experiment. The following words are used to explain my experiment in detail.

1. Equipment

High Temperature Tube Furnace, alumina crucible, heat-proof gloves, 250 mL Erlenmeyer flask, condenser, 250 mL beaker, 50 mL beaker, 100 mL beaker, Buchner funnel, Buchner flask, pH paper, crystallizing dish, thermometer, feeder funnel

2. Materials

Urea, Oxalic acid, Y(NO3)3‧6H2O, Cu(NO3)2‧3H2O, Ba(NO3)2, 95% C2H5OH

3. Procedure

a. Weigh 40 g urea and 3.15 g of oxalic acid, put them into a 250 ml Erlenmeyer flask. Add 18 mL water. Heat them at 70 ˚C until the mixture totally dissolve.

c. weigh 1.900 g Ba(NO3)2, 2.635 g Cu(NO3)2‧3H2O and 1.393 g Y(NO3)3‧6H2O

Heat the solution until it is at 100 ˚C then continue heating for 75 minutes. Evolution of CO2 and NH3 is observed during heating.

e. After 75 minutes of heating, stop stirring. Draw a little clear solution with a pipette, cool the solution to room temperature and measure its pH value with pH paper. when the pH is 7, allow the solution to cool to room temperature.

f. Add about 50 ml water to the solution and stir it. Filter the pale blue precipitate in a Buchner funnel.it is observed that the mixture filters slowly, the way to solve the little problem is to stir the precipitate with 50 ml more water. Wash the precipitate with water followed with alcohol. Place the mixture in a petri dish and let it dry in an oven at 140 ˚C for six hours.

g. Grind the powder. Place the powder in an alumina crucible and calcine it in air. Then heat it at 900 ˚C for 16 hours in a tube furnace.

h. Examine the powder after it has been removed from the oven and cooled. YBa2Cu3Ox is black.

i. Grind the powder in the mortar and pestle. At this stage weigh 1.6 g powder, and mold it into a pellet (3 mm thick, 12 mm in

What can be observed is that a magnet can “fly” on the superconductor. This is called the Meissner effect. (Meissner Effect FP Miller，AF Vandome，J Mcbrewster，Walter，Meissner,2010)The superconducting transition temperature for YBa2Cu3Ox is about 92 K. Cooling a pellet of the material in liquid nitrogen and levitating a magnet over its surface. ( Use the neodymium-iron-boron magnet as they possess stronger magnetic fields which allow the magnet to levitate higher above the superconductor). A pair of plastic tweezers is used to handle the