separation techniques ⋆˚꩜｡
EXPLORING DIVERSITY OF MATTER USING SEPARATION TECHNIQUES
QUICK RECAP
New Substances Creation:
No new substance is created when mixtures are separated.
This process only involves physical separation and no chemical reactions take place.
Separation and Chemical Reactions:
The separation of mixtures does not involve chemical reactions.
PURPOSE OF SEPARATION TECHNIQUES
The ability to separate mixtures into their constituents is essential for reducing, reusing, and recycling, contributing to sustainable living.
Reference: Textbook Pg 80.
CONSIDERATIONS WHEN DECIDING SUITABLE SEPARATION TECHNIQUES
Cost: Economic factors affecting the selection of separation methods.
Reliability: The dependability of the separation technique chosen.
Environmental Impact: Effects of the separation process on the environment.
Physical Properties: Characteristics of the constituents of mixtures that influence the choice of separation technique.
Reference: Textbook Pg 82.
SEPARATION TECHNIQUES
MAGNETIC ATTRACTION
Description: Used to separate magnetic substances from non-magnetic substances.
Example: Only iron filings are attracted by a magnet, while sulfur (non-magnetic) remains behind.
Reference: Textbook Pg 82.
APPLICATION OF MAGNETIC ATTRACTION
Removal of iron from scrap metal in scrap yards using strong magnets for reuse or recycling.
Reference: Textbook Pg 83.
FILTRATION
Description: This technique separates an insoluble solid from a liquid mixture by using a sieve, which separates substances based on different particle sizes.
Example: In a mixture of orange juice and orange pulp, particles larger than the sieve's pores are retained while smaller particles pass through.
Reference: Textbook Pg 84.
FILTER PAPER:
Acts as a sieve, allowing liquid to pass through while retaining solid particles such as chalk in a mixture with water.
Components include filter funnel, filter paper, water (filtrate), and chalk (residue).
HOW DOES FILTRATION WORK?
The filter paper contains tiny pores that permit small liquid particles to pass, but block larger solid particles.
APPLICATION OF FILTRATION
Examples include the use of facemasks, nasal hairs filtering air, and water from siltation ponds.
Reference: Textbook Pg 85.
EVAPORATION
Description: This technique separates a dissolved solute (solid) from a solvent (liquid). It works as the solvent evaporates at a lower temperature than the solute.
Example: In a salt solution, water evaporates leaving behind salt in an evaporating dish.
Reference: Textbook Pg 86.
APPLICATION OF EVAPORATION
Used in the production of preserved food and salt.
ADDITIONAL INFORMATION ON EVAPORATION
Crystallization: The distinction between evaporation and crystallization includes the decomposition of solute upon heating.
- Evaporation requires most solvent to be removed whereas crystallization forms a saturated solution before stopping heating.
SIMPLE DISTILLATION
Description: This method separates substances based on different boiling points through boiling and condensation. It is used primarily to separate a pure liquid (solvent) from a solution.
Detail: The substance with the lowest boiling point evaporates first.
Reference: Textbook Pg 88.
OPERATION OF SIMPLE DISTILLATION:
The apparatus includes a distillation flask to heat the salt solution.
The steam produced passes through a condenser where it cools and condenses back into pure water (distillate). The remaining salt stays in the flask.
Processes Involved: Boiling and condensation.
Property of Distillate: Purity, with fixed melting and boiling points.
DIRECTION OF WATER FLOW
Water in comes from the bottom; water out flows from the top (B.I.T.O).
Reference: Textbook Pg 88.
APPLICATION OF SIMPLE DISTILLATION
Includes making perfumes, producing distilled water, and obtaining drinking water from seawater.
Reference: Textbook Pg 90.
FRACTIONAL DISTILLATION
Used to separate liquid-liquid mixtures, particularly those involving miscible liquids. Miscible means that two liquids can mix together completely without separating into layers. When they are mixed, they form a uniform solution. For example, water and alcohol are miscible because they mix well together.
PAPER CHROMATOGRAPHY
Description: This technique separates small amounts of substances that dissolve to different extents in a solvent.
More soluble substances travel longer distances from the starting point, while less soluble substances remain at the starting point.
Reference: Textbook Pg 91.
OPERATION OF PAPER CHROMATOGRAPHY:
Step 1: A drop of ink is placed near the bottom of a strip of filter paper.
Step 2: The paper strip is dipped into water, which serves as the solvent. The sample spot must be above the solvent level to avoid premature dissolving.
Step 3: Water travels up the paper, carrying the substances in the ink and forming a chromatogram with various colored spots based on solubility.
CHROMATOGRAM DETAILS:
The distances traveled allow identification of substances. Spots that are identical represent the same substance.
The height reached by the solvent is known as the solvent front.
STARTING LINE:
Drawn using pencil (as it is insoluble in solvents) to ensure it does not interfere with results.
Small spots should be used to ensure clear separation without overlap.
SOLVENT LEVEL IN CHROMATOGRAPHY:
The solvent level must remain below the starting line at the beginning of the experiment to prevent the sample from dissolving before separation occurs.
APPLICATIONS OF CHROMATOGRAPHY:
Used to identify colors in dyes, identify colored substances in food products, and detect water pollutants.
Reference: Textbook Pg 92.
TEST YOURSELF!
Scenarios presented to gauge understanding of the discussed separation techniques and applications, including identifying substances and methods of separation based on given mixtures.
Example Test Questions:
Which pen was used to write a note based on chromatography results?
Which samples are mixtures versus pure substances?