Coordination complexes
To show the formation of coordination complexes of copper ions through reactions with water, ammonia and sodium chloride.
Lo que aprenden los alumnos
La base científica de este experimento
When a substance dissolves in water, its molecules and ions are surrounded by water molecules. In some cases the water molecules coordinate with the solute ions, becoming part of a chemical structure with the solute called a coordination complex.
The shape adopted by the complex may be associated with a characteristic colour.
Equipo utilizado
- Test tubes — 1473.60
- Test tube rack — 1680.06
- Test tube holder — 5423.30
- Spatula — 5460.34
- Spirit burner — 5514.10
- Dropping pipette — 1441.50+5448.00
Productos químicos y reactivos
- Copper sulphate — R:22-35/38-50/53 S:22-60-61
- Ammonia
- Sodium chloride
- Distilled water
Notas de seguridad
- Take care when using the burner and hot glassware.
Preguntas para los alumnos
- Record your observation of the colour of the solution and suggest an explanation.
- What happens on adding more ammonia?
- What happens on adding sodium chloride?
Qué puedes esperar
<p>Anhydrous copper sulphate has a dirty white colour, whereas the hydrate CuSO4•5H2O has a blue colour because.</p><p>Dissolving either of these salts in water gives a blue solution because the copper ions coordinate with water molecules.</p><p>Adding a small quantity of ammonia makes the pH of the solution shift towards alkaline values and some copper.</p><p>The precipitate dissolves because a tetraammine complex of copper is formed with the ammonia and a royal blue solution is obtained.</p><p>The solution becomes bright green due to the formation of copper(II) chloride complexes.</p>
Eliminación
Dispose of the solutions into the liquid wastes container.
Realiza este experimento en tu clase
Este experimento forma parte del « Mobile Lab » de ATP, un laboratorio autónomo que convierte un aula normal en un laboratorio de ciencias en pleno funcionamiento, con más de 200 experimentos de física, química, biología, robótica e ingeniería. « Gali », el tutor de IA integrado en ATP Connect, guía a los alumnos paso a paso y responde a sus preguntas en la mesa de trabajo.
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