Activity 5.1 To identify whether the given mixtures are a true solution. Class 9

Activity 5.1 To identify whether the given mixtures are a true solution. Class 9

Activity 5.1

Aim: To identify whether the given mixtures are a true solution, a suspension, or a colloid.

Materials Required: Two glass beakers, Water, Salt or sugar, Sand, Spoon

Procedure:

1. Take three beakers and label them (a), (b) and (c).
2. In Beaker (a), add water and mix some salt (or sugar). Stir well
3. In Beaker (b), add water and mix chalk powder. Stir it.
4. In Beaker (c), add milk with water. Stir it.

Observation:

Beaker (a) (Salt + Water):

1. Appears clear and uniform.
2. No visible particles to the naked eyes.
3. The path of the laser beam is visible.
4. Salt completely dissolves

Beaker (b) (Chalk powder + Water):

1. Appears cloudy or non-uniform,
2. Sand particles are clearly visible,
3. Sand settles at the bottom, so the path of the laser beam is visible.

Beaker (c) (Milk + Water):

1. Appears cloudy and uniform.
2. No visible particles to the naked eyes.
3. The path of the laser beam is visible (Tyndall Effect).
4. On standing, particles do not settle.

Conclusion:

1. Homogeneous mixture: Uniform composition (salt + water)
2. Heterogeneous mixture: Non-uniform composition (chalk power + water)
3. Appears Homogeneous mixture: Shows Tyndall effect, does not settle, (milk + water)

This activity shows that mixture differ based on particle size, visibility, stability and light scattering properties.