Page 178 - ICSE Chemistry 8

Procedure
• Line up the fi ve glasses and pour water in them, fi lling each glass ll half.
• Put one tablespoon each of the substances in separate glasses like sodium chloride in the fi rst glass,
sodium carbonate in the second glass and so on.

• Now s r each mixture with a spoon.
Observa on: You will observe that all the substances completely dissolve on water and a clear, transparent
solu on is obtained in each case.

Conclusion: It can be concluded that water has the ability to dissolve many substances.

Factors Affecting the Formation of a Solution

There are certain factors that aff ect the forma on of a solu on as discussed here.
• Size of the par cles: The rate of the forma on of the solu on is faster if the size of the par cles of
solute is smaller.

• S rring: S rring increases the rate of forma on of a solu on.
• Increase in temperature: The rate of forma on of a solu on increases on hea ng the solu on.

Activity 8.6

Aim: To show that s rring, hea ng and the small size of par cles of a solute increase the rate of forma on
of a solu on
Materials required: Five beakers, some water at room temperature, some hot water, some powdered
sugar, fl ew lumps of sugar
Procedure

• Take fi ve beakers and label them as A, B, C, D and E.
• In beaker A, take water at room temperature and
powdered sugar.
• In beaker B, take water at room temperature and
lumps of sugar.

• In beaker C, take hot water with lumps of sugar.
• In beaker D, take hot water with powdered sugar.

• In beaker E, take hot water at room temperature and powdered sugar.
• S r the powdered sugar added to the beakers A, B, C and D. However, do not s r a er adding the
powdered sugar in beaker E.
Observa on: You will observe that the sugar in beaker A dissolves faster than in beaker B. The sugar in
beaker D dissolves faster than that in beakers C and E.

Conclusion: This shows that the rate of forma on of a solu on increases with s rring, hea ng and addi on
of small-sized par cles of a solute.

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