Chemistry Reference
In-Depth Information
Experiment 1
. Fill the glass dish half-full with water and throw in a piece of lithium
with the help of tweezers (do not touch it with your fingers!). Record your
observations!
Experiment 2
. You may notice a gas formation in experiment 1. That gas is
presumed to be hydrogen. Try to collect and confirm the hydrogen gas. Therefore,
fill the glass dish half-full with water. Then fill up the cylinder with water and close
it with the cover glass. Hold on to the cover glass, turn the cylinder around and put it
into the glass dish, so that the opening is under the water surface (see figure). Now
remove the cover. Take the second piece of lithium with the tweezers, hold it under
the opening of the cylinder, and let it rise into the cylinder.
After the reaction cover the cylinder with the cover glass under water (press on
tightly!) and take it out of the glass dish. Turn it around again. Ignite the gas!
Record your observations!
Experiment 3
. The produced solution is called lithium hydroxide solution; this can
be shown with indicator paper. Test pure water and the solution with indicator paper
by dipping it in briefly. Compare it to the color scale. Note both pH-values.
Experiment 4
. Another indicator for lithium hydroxide solution is phenolphthalein
solution. Pour a couple of drops into pure water and into the solution. Record your
observations.
Experiment 5
. Wash out the glass dish and fill it half-full with water and add some
drops of phenolphthalein solution. Throw in the third piece of lithium. Record your
observations.
Exercise:
Explain all observations. Write reaction equations in words and in
formulae! Draw your mental models of the reactions.
References
1. Liebig J (1840) Der Zustand der Chemie in Preußen. Ann Chem Pharm 34:97
2. Stroker E (1967) Denkwege der Chemie. Alber, Freiburg
3. Anschuetz R (1929) Leben und Wirken. Baende 1-2. Chemie, Berlin
4. Kekul
´
A (1866) Lehrbuch der Organischen Chemie. Baende 1-3. Chemie, Erlangen
5. Von Laue M (1961) Mein physikalischer Werdegang. Eine Selbstdarstellung. Vieweg,
Braunschweig
6. Von Laue M (1923) Die Interferenz der Roentgenstrahlen. In: Ostwalds Klassiker Nr. 204.
Engelmann, Leipzig
7. Wiederholt E (1999) Gaschromatographie - Nachweis von in Wasser gelostem Sauerstoff und
Stickstoff. MNU 52:92
8. Brockmeyer H (1973) Rontgenstrahlen im naturwissenschaftlichen Unterricht. Aulis, Koln
9. Schwedt G (1991) Chemie zwischen Magie und Wissenschaft. VCI, Weinheim
10. Gilbert L et al (1994) Tested demonstrations in chemistry. ACS, Granville
11. Shakhashiri B (1983) Chemical demonstrations. University of Wisconsin, Madison
12. Gl
ockner W et al (1994) Handbuch der Experimentellen Chemie. Aulis, K
oln
€
€
13. Arendt R, D
ormer L (1980) Technik der Experimentalchemie. Quelle + Meyer, Heidelberg
14. Meyendorf G et al (1979) Chemische Schulexperimente. 5 Bd. Deutsch, Frankfurt
15. Schmidkunz H, Lindemann H (1992) Das forschend-entwickelnde Unterrichtsverfahren.
Westarp, Essen
€
