WRITE THE PROSSESS
1. Preparation of true common salt solution, sugar and alum.
2. Preparation of suspension of soil, chalk powder, fine sand in water.
3. Preparation of stained temporary mounts of onion peel and human cheek cells.
4. Identification of simple permanent tissues in plants.
5. Determination of density of solid using spring balance and measuring cylinder.
Answers
Answer:
To prepare
A true solution of common salt, sugar and alum.
A suspension of soil, chalk powder and fine sand in water.
A colloidal solution of starch in water and egg albumin in water and distinguish between these on the basis of
transparency
filtration
stability.
MATERIALS REQUIRED
Test tubes, beakers, water, common salt, sugar, alum, soil, chalk powder, fine sand, egg albumin, starch, funnel, glass rod, filter paper.
THEORY
A true solution has particle size < 10-9 m. It is a homogeneous mixture which is clear and transparent. It passes through the filter paper easily and is stable.
Colloid has particle size 10-9 m- 10-6 m. It is heterogeneous and is translucerft. It passes through filter paper and is stable.
The particle size of Suspension is >10-6 m. It is heterogeneous and opaque. Its particles do not pass through filter paper and settle under gravity when left undisturbed for sometime.
PROCEDURE
Preparation of solutions/mixtures
Take 8 beakers and label them as A, B, C, D, E, F, G and H and add 50 ml of water to each of these beakers.
Add samples of salt, sugar and alum to beakers A, B and C. Stir to make clear solution.
Add soil, chalk powder and fine sand to beaker D, E and F. Stir for sometime.
Add a small amount of starch to the water and boil the content in beaker G.
In beaker H, add egg albumin and stir vigorously.
Observe the mixture and record them in the table given below.
OBSERVATION TABLE
CBSE Class 9 Science Practical Skills - Solution, Colloids, Suspension 1
CBSE Class 9 Science Practical Skills - Solution, Colloids, Suspension 2
CBSE Class 9 Science Practical Skills - Solution, Colloids, Suspension 3
CBSE Class 9 Science Practical Skills - Solution, Colloids, Suspension 4
RESULTS
Beaker A – Common salt forms a true solution in water.
Beaker B – Sugar forms a……………. in water.
Beaker C – Alum forms a …………….in water.
Beaker D – Soil forms a……………. in water.
Beaker E – Chalk Powder forms a……………. in water.
Beaker F – Fine sand forms a……………. in water.
Beaker G – Starch forms a……………. in water.
Beaker H – Egg albumin forms a …………….in water.
PRECAUTIONS
Distilled water should be used.
The components should be mixed in small amounts.
Fold the filter paper properly and moisten it before use.
Glass rod should be clean.
Wash your hands properly with soap after experiment.
Explanation: