CATALYTIC OXIDATION OF NATURAL GAS BY PLATINUM Submitted by: , William C. Cooper, Methodist College, Fayetteville, N. C. Checked by: Mary Jane Wolf, Hillside Junior High School, Parma, Ohio PREPARATION
Have available two Bunsen burners, platinum wire or gauze, and a supply of natural gas. DEMONSTRATION
Adjust the burners to a medium flame, and hold the wire or gauze in one of the flames until the metal becomes red hot. The flame of the other burner is interrupted by pressing on the tube, thus shutting off the flow of gas to the burner momentarily. The pressure is then released, and the hot platinum is held in the gas-air stream of the blacked-out burner. The wire or gauze continues to glow, and the intensity varies as the
platinum is moved to different locations in the gas jet. The gases do not ignite unless the wire is moved close to the tip of the burner where the reaction is more intense and is sufficient to cause the gases to burst into flame. REMARKS
Various concepts pertaining to the oxidation reaction may be discussed, such as: Exothermic character Activation energy requirements, with and without the catalyst Effect of catalyst Heat of reaction Ignition temperature Journal of Chemical Education
June 1968
LE CHATELIER'S PRINCIPLE Submitted by: Adrian L. Melott, Bethany College, Bethany, W. Va. 26032 Checked by: Sosinsky, Brooklyn College of Pharmacy, Brooklyn, N. Y. PREPARATION
Provide three 250 ml Erlenmeyer flasks each containing 100 ml cone. NH3 solution, 8 g dry NaOH pellets, 14 g dry KOH pellets, 10 g dry NaCl, phenolphthalein solution (if desired), fume hood, and safety glasses. DEMONSTRATION
Under the hood add the NaCl, NaOH, and KOH, in that order, one to each of the NH3 solutions. Note the evolution of gas bubbles. Odor and wet litmus may
be used to test for NH3 gas. Bubbling may be made more visible by adding phenolphthalein to the flasks. REMARKS
The high solubility of NH3 and the subsequent reaction provides a limited number of O H ious. Upon addition of a base, such as NaOH, a large quantity of additional OH- ious are produced. These additional OH- ions cause the reaction between the NH3and water to be reversed and NHa is released. The relative activity of NaOH and KOH i s shown. NaCl confirms that the phenomenon is not due to salting out. J n d
of Chemical Education
. June 1988
