Colloids
To introduce colloidal solutions and familiarise students with filtering techniques.
Lo que aprenden los alumnos
La base científica de este experimento
In the previous experiments the solutes were dispersed as molecules or ions throughout the solvent. It can happen that the solute does not dissolve completely but its molecules remain aggregated as small clusters; these solutions are called colloids and have different properties from true solutions.
Under certain conditions, it is possible to obtain colloids from a wide range of substances, such as metals, oxides and sulphides.
Some colloids, such as soaps, form micellar solutions where the solute exists as particles called micelles.
Equipo utilizado
- Test tubes — 1473.60
- Test tube rack — 1680.06
- Test tube holder — 5423.30
- Spatula — 5460.34
- Iron stand — 5404.52
- Universal clamp — 5416.20
- Right angle clamp — 5401.16
- Glass funnel — 1343.15
- Filter paper — 8340.08
Productos químicos y reactivos
- Sulphur — R:11-16 S:41
- Ethanol — R:11 S:7-16
Notas de seguridad
Preguntas para los alumnos
- Describe the solution. What was it like before and after the addition of water?
- What happens to the solution after filtration? Why?
Qué puedes esperar
<p>The sulphur dissolves in ethanol to give a clear, pale yellow solution. After adding water, the colloidal solution looks like a milky white solution.</p><p>The same results are obtained with milk that forms micelles with water molecules.</p><p>Filtration does not affect the solution because the sulphur particles are much smaller than the pores in the paper.</p>
Eliminación
Dispose of liquids 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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