Question

Which separation method is operating in each of the following procedures? (a) Pouring a mixture of cooked pasta and boiling water into a colander (b) Removing colored impurities from raw sugar to make refined sugar

Short answer

(a) Filtration (b) Crystallization

Step-by-step solution

Identifying the Separation Method for Pasta and Boiling Water

To separate cooked pasta from boiling water by pouring the mixture into a colander, we use the method of filtration. Filtration involves passing a mixture through a filter (in this case, the colander) that allows the liquid to pass through while retaining the solid components (the pasta).

Identifying the Separation Method for Raw Sugar Impurities

To remove colored impurities from raw sugar to make refined sugar, we use the method of crystallization. Crystallization involves dissolving the impure sugar in a solution and then allowing pure sugar crystals to form, leaving the impurities behind. This process effectively separates the pure substance from the impurities based on their different solubility.

Key concepts

filtration

Filtration is a common method used in chemistry and daily life to separate different components of a mixture.
It works by passing the mixture through a filter, which allows only certain components to pass through. Typically, this method is used to separate solids from liquids or gases.
For instance, in the exercise, pouring a mixture of cooked pasta and boiling water into a colander is an example of filtration.
The colander acts as a filter that retains the solid pasta while allowing the liquid water to drain away.

• This process is crucial for making pasta dishes less watery.
• It is widely used in laboratory settings to separate precipitates from solutions.

Filtration is simple but highly effective, making it indispensable in both laboratory and household settings.

crystallization

Crystallization is a purification technique often used to separate and purify substances.
This method takes advantage of differences in solubility between the desired component and impurities. For instance, when removing colored impurities from raw sugar to make refined sugar, crystallization is employed.
Here’s how it works:

• The impure sugar is first dissolved in a solution.
• As the solution cools or evaporates, pure sugar crystals start to form and grow.
• The impurities, which do not crystallize as easily, remain in the solution.

The pure sugar crystals can then be collected and separated from the remaining solution of impurities.
This method is essential in industries like food production and pharmaceuticals, where purity is critical.

mixture separation

Separation methods in chemistry are vital for isolating components of a mixture.
Different methods are used depending on the properties of the components. For example, filtration and crystallization are two of the most commonly used separation techniques.

• Filtration uses a filter to separate solids from liquids or gases based on particle size.
• Crystallization leverages differences in solubility to purify substances.

These techniques are often combined to achieve a greater level of purification or separation.
Understanding which method to use requires knowledge of the physical and chemical properties of the substances involved.
Whether in a lab or a kitchen, mastering these techniques is crucial for successful chemical operations.