SOLUTIONS by anza antony

SOLUTIONS

anzaantony2018 — 2020-10-10 07:24:36 UTC

The figure shows different types of solutions. There are many instances where solutions are made use of.

anzaantony2018 — 2020-10-10 07:27:42 UTC

INTRODUCTION
Is there any relation between the state of the solution and that of the solvent? In most of the cases, the physical states of the solvent and the solution are the same.
How do we decide the solvent and the solute in a solution?
Normally,the constituent present in smaller amount is considered as the solute and the constituent present in larger amount is considered the solvent. In aqueous solutions, water is always the solvent irrespective of its amount.

Concentration of a solution

anzaantony2018 — 2020-10-10 07:35:10 UTC

Concentration of a solution refers to the amount of solute dissolved in a fixed amount of solvent. A solution containing a small amount of solute is known as a dilute solution and that which contains large amount of solute is known as a concentrated solution.

Saturated solution

anzaantony2018 — 2020-10-10 13:49:43 UTC

Do different materials dissolve to the same extent in a given solvent?
Take 50 ML each of water in two beakers.Take 100 g each of powdered common salt (sodium chloride) and ammonium chloride. Stir and dissolve the common salt gradually in the water in one of the beakers. Continue doing this till no more salt dissolves.Such a solution, in which maximum amount of solute has been dissolved, is known as a saturated solution.

 The solution obtained by dissolving maximum amount of solute at a given temperature is known as a saturated solution.

The solution before reaching saturation is known as an Unsaturated solution. Unsaturated solutions can dissolve more amount of solute.

The amount of salt that is used to prepare the standard solution can be found out from the amount of salt that is left behind.
Repeat the above activity by adding ammonium chloride gradually to the second beaker. Is it possible to prepare the saturated solution of ammonium chloride this way?
Compare the amount of ammonium chloride with that of common salt .Which is greater ?Find out .It is now clear that the amounts of common salt and ammonium chloride required to make a saturated solution using the same solvent under the same condition differ.

The amount of a solute in grams required to convert 100g of a solvent into a saturated solution at a given temperature is known as the solubility of the solute in that solvent.

Saturated V/S Unsaturated

anzaantony2018 — 2020-10-10 16:41:32 UTC

Supersaturated solution

anzaantony2018 — 2020-10-10 17:06:08 UTC

Is it possible to dissolve more amount of the solutes in the saturated solutions prepared before?
. Is there any change in the amount of solute
dissolved when the temperature changes?

Add a little more of common salt to the saturated salt solution and heat it. What happens ?Does it get dissolved ?Repeat the experiment with the saturated solution of ammonium chloride.
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Leave these solutions undisturbed and allow them to cool gradually to the room temperature.
Observe the two solutions. Does crystallization occur?
Such a solution which contains more amount of solute than that is required to saturate it,is known as a supersaturated solution.

The nature of solute and the temperature are two factors that influence solubility.

Example for supersaturated solution

anzaantony2018 — 2020-10-11 06:07:43 UTC

anzaantony2018 — 2020-10-11 06:35:20 UTC

Classification of mixtures

anzaantony2018 — 2020-10-11 07:06:36 UTC

All solutions are mixtures. Still, do all mixtures exhibit the same nature?
If the composition of the constituents is the same throughout the mixture ,it is known as a homogeneous mixture. All solutions are homogeneous mixtures.Eg. sugar solution, salt solution, air , ornamental gold.
The components of such mixtures cannot be seen separately with the naked eye.
If the components in a mixture are not distributed uniformly ,it is known as heterogeneous mixture.Eg. a mixture of salt and sand ,muddy water, a mixture of water and kerosene.

Here the components can be seen separately with the naked eye.

True solution, Colloid, Suspension

anzaantony2018 — 2020-10-11 07:31:26 UTC

True solution is a homogeneous mixture of two or more substances in which substance dissolved(solute) in solvent has the particle size of less than 10^-9m or 1nm. Simple solution of sugar in water is an example of true solution. Particles of true solution cannot be filtered through filter paper and are not visible to naked eye.

Suspension is a heterogeneous mixture in which particle size of one or more components is greater than 1000nm. When mud is dissolved in water and stirred vigorously, particles of mud are distributed evenly in water. After sometime, the particles of this solution settle under water due to influence of gravity. Contrary to True Solution,particles of suspension are to be big enough to seen with naked eye.

Colloidal solution is a heterogeneous mixture in which particle size of substance is intermediate of true solution and suspension i.e, between 1-1000nm. Smoke from a fire is example of colloidal system in which tiny particles of solid float in air.Just like true solutions, Colloidal particles are small enough and cannot be seen through naked eye. They easily pass through filter paper.But colloidal particles are big enough to be blocked by parchment paper or animal membrane.

anzaantony2018 — 2020-10-11 07:33:05 UTC

Soft drinks

anzaantony2018 — 2020-10-11 07:49:04 UTC

Most of the juices that we drink are liquids in the colloidal form.Such juices and liquids are available in the market. They do not settle down even after prolonged storage.
How are they retained as such for long periods of time without settling down?Do you know that some substances are added for this purpose ?Such substances are called stabilisers.
Are chemicals added to soft drinks only for this purpose?
What are the other purposes for which chemical substances are added in soft drinks?
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Stabilisers
Some chemical substances used as stabilisers in soft drinks to prevent the particles from getting settled are:
. Brominated vegetable oil
. Sucrose acetate isobutyrate
. Glyceryl ester or Rosin.