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solute
Salt is the dissolved substance.
Class 6 · English Version · General science
2026 Class 6 Science · English Version · Chapter 8 · Chapter companion part
Chapter 8: Mixture
Describe solutions and choose a separation method suited to a mixture.
Class 6 English Version chapter companion with expanded teaching, 20 written tasks and a notebook challenge. Further independent assessment and teacher-reviewed practical work remain; this is not complete textbook coverage.
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Learn the idea
A mixture contains substances combined without making one new chemical substance. In a solution, a solute dissolves in a solvent; a salt solution is a homogeneous mixture. Sand in water is heterogeneous because its composition is not uniform. Dissolving does not mean the solute has disappeared or been destroyed.
Saturation and solubility
At a stated temperature, a saturated solution holds as much of a particular solute as can dissolve under those conditions. Solubility states how much dissolves in a specified amount of solvent, so the units and temperature matter. Stirring often speeds dissolving but does not necessarily increase the maximum amount that can dissolve.
Separation by properties
Filtration separates an insoluble solid from a liquid; dissolved salt passes through ordinary filter paper. Evaporation can recover a dissolved solid; distillation evaporates then condenses solvent to collect it. Decanting separates liquid from a settled solid, and immiscible liquids form layers. Select the method by the property and the substance you want.
Other mixtures and precautions
Gases can dissolve in liquids, as oxygen does in water. Water dissolves many substances but not everything. Temperature can affect solubility differently for different substances. Use room-temperature salt, sand, paper diagrams or supplied results here; do not taste mixtures, use solvents or boil liquids without a teacher.
Solutions, suspensions and colloids
A true solution has solute distributed on a very small scale and does not ordinarily settle on standing. A suspension has larger dispersed particles that can settle, such as coarse mud in water. A colloid has dispersed particles that do not readily settle. Milk is a colloidal emulsion: droplets of one liquid are dispersed in another. Colloids can scatter light. Appearance alone does not establish safety or identify every component.
Measure a solution rather than just stir
State the solute, solvent, amount and temperature. A saturated solution has reached the amount of that solute that can dissolve under the conditions. More stirring may speed dissolving but does not necessarily increase this capacity. For a supplied mass example, 5 g solute plus 95 g solvent gives 100 g solution if no material is lost. Mass of solution and mass of solvent are different quantities.
Choose what to recover
Filtration leaves an insoluble residue on the filter and collects a filtrate below. Dissolved salt usually stays in the filtrate. Evaporation or crystallisation can recover a dissolved solid; distillation also condenses vapour to collect solvent. A condenser removes energy from vapour. Cooling can make crystals when solubility falls, but solubility changes depend on the substance and temperature. Distillation is not a universal way to remove every possible contaminant.
Everyday uses and a safe plan
Tea, food mixtures, paint and naturally occurring muddy water illustrate different mixture behaviours. Water dissolves many substances, not everything; oil and water can form separate layers. Use supplied observations, clean room-temperature materials or diagrams. Do not taste samples or use a medicine mixture as an experiment. Heating, glass distillation apparatus and chemical solvents require a teacher’s appropriate practical setup.
Worked example
To recover salt from salt-and-sand water: filter out the insoluble sand, then obtain salt from the filtrate by a suitable evaporation/crystallisation process. The filter alone does not remove dissolved salt.
- Identify the evidence, quantity or structure in the question.
- Write a labelled method or explanation; include units where needed.
- Check the model, explain one correction, then attempt the independent task.
Check a common mistake
Water is often called a universal solvent because it dissolves many substances. It does not dissolve everything, and a clear solution is not automatically safe to drink.
Keep the solvent amount clear
A supplied solubility is 25 g solute per 100 g water at a fixed temperature. For 50 g water the corresponding maximum is 12.5 g in this model. This is not 25 g per 100 g of finished solution.
Follow both components
For salt and sand mixed with water, filtration can leave sand as residue while salt solution passes through. A later suitable crystallisation step recovers salt; distillation can collect water if that is the desired component.
Your written practice
Show your working on paper and enter your answer here. If it does not match, compare the model and try again.
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solvent
Water is the dissolving medium.
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filtration
Insoluble sand is retained by the filter.
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unsaturated
It has not reached its dissolving capacity under those conditions.
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40
Twice the solvent mass holds twice the given amount in this model.
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Dissolved salt passes through the filter with the water; it is not trapped as an insoluble solid.
Connect the method to particle size/solution state.
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Distillation: evaporate water, then condense and collect it. Evaporation alone does not collect the vapour.
State the desired component and both steps; no home heating procedure is required.
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Stirring can speed the approach to saturation without changing the maximum amount that dissolves at a fixed temperature.
Distinguish rate from final capacity.
Take it further
Apply the idea in a new situation and explain your method. Open writing needs a guardian or teacher to review it.
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filtrate
The filtrate passes through; insoluble residue stays on the filter.
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residue
Residue is retained by the filter.
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suspension
Larger dispersed particles can settle.
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colloid
Milk is a familiar colloidal emulsion.
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100
7 + 93 = 100 g; do not confuse solvent mass with solution mass.
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12.5
25 × 50 ÷ 100 = 12.5 g in the supplied model.
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The dissolved salt passes through the filter with the water; visual clarity does not mean the solute is absent.
Explain what filtration can and cannot retain.
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The solvent vaporises, then vapour loses energy and condenses into a collected liquid.
Identify the substance followed through both changes.
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Cooling does not reduce every solute’s solubility in the same way; the substance and conditions determine whether crystals can form.
Avoid a rule that all cooling always makes crystals.
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Use supplied information or observe safe samples for settling and light scattering under teacher-approved conditions; record the limits of appearance alone.
Give a non-tasting observation and avoid treating one sign as a complete identification.
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Use an appropriate teacher-supervised distillation model to collect condensed water while salt remains, with a later suitable solid-recovery step if needed.
State the desired components and why collecting vapour matters.
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Oil does not mix into an ordinary true solution in water under these conditions. Water dissolves many substances but not all.
Use a suitable example and a qualified statement.
Your science notebook challenge
Draw a separation flow chart for a supplied sand–salt–water mixture, naming residue, filtrate, recovered solid and collected solvent. Compare one solution, suspension and colloid using non-tasting observations or supplied data.
Review with a guardian or teacher
- Use an observation, labelled diagram or stated data.
- Explain how the evidence supports your answer.
- Record one limitation or correction with a guardian or teacher.
Keep your work on paper or in a local file. This page does not upload it or automatically grade the project.
Chapter companion and further study
This original Kidemy practice follows the topic order of 2026 Class 6 Science · English Version, chapter 8, printed pages 70–84. It does not replace the complete chapter or its practical teaching.
Official book catalogue and source →
Continue with your book or teacher
- Independent mixture-identification and separation-plan assessment
- Teacher-reviewed solution preparation, crystallisation and distillation interpretation
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