Science · Properties used to separate mixtures
Edited by: Hitoiki Arcade / Hitoiki Learning team · Published: · Editorial policy
Water containing sand and water containing dissolved salt are both mixtures. Does filter paper separate them in the same way? Before recalling a method, identify what is mixed and whether it is dissolved.
The matter guide distinguished pure substances from mixtures. Here we compare properties used to separate components. In three examples, find the condition that selects filtration, distillation or recrystallization.
The first question specifies insoluble sand in water and passage through filter paper. Choose “Filtration”: the sand stays on the paper while water passes through. The question describes neither collecting vapor nor forming crystals from a dissolved solid.
Ordinary filter paper does not recover salt dissolved in water. Removing undissolved particles differs from separating dissolved components. Clear-looking water need not be free of dissolved substances.
The second question specifies a liquid mixture and differences in boiling behavior, so choose “Distillation.” The vapor is cooled back into liquid and collected. Follow what is recovered, rather than stopping at the idea of heating.
Vapor from a mixture can be enriched in the more volatile component. That does not mean only that component evaporates, or that different boiling points guarantee complete separation in one pass. This example asks which property the method uses.
In the third question, temperature-dependent solubility means that the limiting amount that can dissolve changes with temperature. Choose “Recrystallization”: dissolve a solid and recover it as crystals to purify it. For the cooling-based method discussed here, a suitable solvent dissolves the desired compound well when hot and poorly when cold.
The liquid left after collecting the crystals is the mother liquor. Readily soluble impurities can remain there, while insoluble impurities may need separate filtration. Some desired compound can also remain in the mother liquor: purification does not mean recovering everything.
On paper, write “filtration / distillation / recrystallization” and add each question’s deciding condition: undissolved particles; boiling behavior and liquid recovery; solubility changing with temperature. The same choices can produce different answers because the properties differ.
The practice button selects basic elementary-, middle- and high-school questions on substances and separation, including matching questions beyond these three. Revisit the matter guide for mixture classification or the related solutions and acids guide for concentration.
TRY & READ
Compare the choices before opening the answer and explanation. Reading an example does not save a test answer or score.
Example 1 · Chemistry: substances and separation
Answer: Filtration
Water passes through the filter while the sand particles are retained.
Example 2 · Chemistry: substances and separation
Answer: Distillation
A component evaporates and is then cooled and collected as a liquid.
Example 3 · Chemistry: substances and separation
Answer: Recrystallization
Crystals form as the solution cools, while impurities can remain in the liquid. Recrystallization dissolves a solid and then forms crystals again. Soluble impurities can stay in the remaining liquid; insoluble impurities may instead need hot filtration.
Source checked: 2026-10-29
Source checked: 2026-10-29
Source checked: 2026-10-29
Source checked: 2026-10-29
Source checked: 2026-10-29
Source checked: 2026-10-29
Topics: Chemistry: substances and separation. Range: Everyday knowledge, Broader knowledge, General knowledge. Difficulty: Basic. These are selected initially. You can change these on the setup screen.
Try this topic in a quizThis opens the setup screen with this subject and topic selected. Check the mode and question count before you start.
A test shows explanations after submission. Continuous challenge explains each answer. Review uses unresolved mistakes recorded on this device. Casual mode does not update learning records.
Only the page address is shared. Your saves and results are not included.