Page 85 - ICSE Chemistry 6
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A solu  on is said to be saturated when it cannot dissolve any more of the solute at a par  cular temperature.
                 A solu  on is said to be unsaturated when it can dissolve more of the solute at a par  cular temperature.
                 A solu  on is said to be supersaturated when it contains more solute than can be dissolved in the solvent
                 under normal condi  ons.
                 Let’s perform Ac  vity 4.10 to prepare a saturated solu  on of salt and water.

                           Activity 4.10


                 Aim: To prepare a saturated solu  on of salt and water

                 Materials required: A beaker, some water, a spoon, some salt
                 Procedure
                   •  Take some water in a beaker.

                   •  Add a teaspoon of salt to it and s  r it.
                   •  Con  nue adding salt   ll no more salt can be dissolved in it.
                 Observa  on: A  er a point salt stops dissolving in water.

                 Conclusion: The solu  on, so obtained, in which no more salt can be dissolved at this par  cular temperature
                 is a saturated salt solu  on.


                 The forma  on of a solu  on is a physical change. Molecules of the solute and the solvent remain the same
                 in a solu  on. It is easy to get back the solute and the solvent in their original form from the solu  on. Let’s
                 perform Ac  vity 4.11 to observe how salt can be separated from a salt solu  on.


                           Activity 4.11

                 Aim: To separate salt from salt solu  on by evapora  ng   ll the water dries

                 Materials required: A beaker, some water, a spoon, some salt, an evapora  ng dish, a burnerner
                 Procedure
                   •  Take some water in a beaker and add two teaspoons of salt to it.

                   •  S  r the contents of the beaker. You will get a salt solu  on.
                   •  Transfer this salt solu  on to an evapora  ng dish.

                   •  Now heat the dish over the fl ame of a burner.
                   •  Observe what happens a  er 15–20 minutes.
                 Observa  on: You will observe that a  er some   me water starts boiling and turning into water vapour.
                 If the vapour coming out of the solu  on are allowed to condense, then we can obtain the solvent. A  er
                 some more   me, a stage will come when no more water is le   in the evapora  ng dish and only salt is
                 present at the bo  om of the beaker.

                 Conclusion: This way, salt (solute) can be separated from salt solu  on.


                 From Ac  vity 4.11, we can conclude that a solvent can be obtained from a solu  on by the process of
                 dis  lla  on, while a solute can be obtained by evapora  ng the solu  on   ll it dries.


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