Question

Define saturated, unsaturated, and supersaturated.

Short answer

Saturated: maximum solute dissolved. Unsaturated: less than maximum solute. Supersaturated: more solute than saturated, unstable.

Step-by-step solution

Understanding Saturated Solutions

A saturated solution is a solution in which the maximum amount of solute has been dissolved in the solvent at a given temperature. No more solute can dissolve under these conditions, and any additional solute will remain undissolved in the mixture.

Understanding Unsaturated Solutions

An unsaturated solution is one in which less than the maximum amount of solute is dissolved in the solvent at a given temperature. Additional solute can still be added and dissolved in the solution without any undissolved solute being present.

Understanding Supersaturated Solutions

A supersaturated solution contains more solute than a saturated solution at the same temperature. This is usually achieved by changing conditions, such as cooling a saturated solution slowly. Supersaturated solutions are unstable, and excess solute may precipitate out if the solution is disturbed or if a seed crystal is added.

Key concepts

Saturated Solution

In chemistry, a saturated solution is one where the solvent has dissolved the maximum possible amount of solute at a given temperature. This means that the solution is in a state of equilibrium. Any additional solute added under these conditions will simply not dissolve, instead forming a residue at the bottom of the container. For example, if you keep adding sugar to a cup of tea and eventually notice that the sugar no longer dissolves but collects at the bottom, you have created a saturated solution.

Saturated solutions have some interesting characteristics:

• Dynamic Equilibrium: At a saturated state, the solutions are at equilibrium, where the rate of solute dissolving equals the rate of solute crystallizing out.
• Temperature Dependence: The amount of solute that can dissolve depends significantly on temperature. Many solutes, like salts, dissolve more as temperature increases.
• Uses in Real Life: Saturated solutions are critical in various industries, such as creating specific saturated brines for food preservation or managing mineral scaling in water systems.

Unsaturated Solution

An unsaturated solution is the opposite of a saturated solution. It means the solvent can dissolve more solute. In everyday terms, the solution could be described as being 'thirsty' for more solute. For instance, when you add a spoonful of sugar to a cup of freshly brewed iced tea and the sugar dissolves, you have an unsaturated solution because more solute can still be added without any visible sugar grains.

Unsaturated solutions have flexible properties:

• Solute Potential: There's still room for more solute to dissolve, which means you haven’t reached the solute capacity of the solvent.
• Manipulation of Solubility: Changing the temperature or pressure can alter the point at which a solution becomes saturated, which is particularly useful in chemical reactions and solutions preparation.
• Applications in Dilution: Unsaturated solutions are often used when dilution is necessary, such as in preparing medications or preparing solutions in the laboratory where precise concentrations are required.

Supersaturated Solution

Supersaturated solutions are fascinating chemical mixtures where the solution contains more solute than what would typically dissolve at a certain temperature. It is a state achieved through careful manipulation and requires meticulous preparation. This can be done by dissolving solute in a solvent at an elevated temperature and slowly cooling the solution. Example can be seen in certain beverages where excess sugar remains dissolved due to higher preparation temperatures.

Supersaturated solutions are unique because:

• Highly Unstable: These solutions are prone to precipitate. The addition of a seed crystal or even a slight mechanical disturbance can trigger crystallization of the excess solute.
• Special Conditions for Creation: Achieving supersaturation often involves controlled variations in temperature or pressure, allowing solute to remain in solution beyond its normal saturation point.
• Intriguing Applications: They are used in creating crystal formations for scientific study, in hand warmers through exothermic crystallization processes, and in candy making, as seen in rock candy production.