| time
requ.: |
10 minutes. |
|
objective: |
Synthesis from elements,
exothermic reactions, compounds from elements by chemical reactions. |
| material: |
- test tube d=18mm
- test tube holder
- tripod
- wire screen
|
|
| chemicals: |
- zinc powder
- sulphur powder
|
|
|
procedure 1: |
Mix 13,1g zinc powder with
6,4g sulphur
powder and compare the colour of the mixture with pure substances. Put
the mixture on the wire screen (tripod) under the fume hood and ignite it with burner. |
|
observation 1: |
Fast reaction
with fire and white smoke,
then yellowish-white product. |
|
interpretation 1: |
Zn + S ---> ZnS
zinc sulphur zinc sulphide |
|
procedure 2: |
Evaporate sulphur in a test tube
an add a piece of copper foil. |
|
observation 2: |
Red glowing,
then dark coloured product. |
|
interpretation 2: |
Cu + S ---> CuS
copper sulphur copper(II)-sulphide |
|
source: |
Proc. 2 from Barke, H.-D. et al.: One Hundred
Chemistry-Experiments to Avoid Chalk and Talk; University of Muenster,
2004. Proc. 1 from Wagner, W., Department of
Chemistry Education, University of Bayreuth. |
