separating mixtures by physical properties — HSC chemistry year 11, live

Separating mixtures by physical properties

A mixture is two or more substances physically combined, not chemically bonded, so each one keeps its own physical properties. Separating a mixture means finding a property the components differ in (magnetism, particle size, solubility, density or boiling point) and choosing the technique that exploits it. Weigh each recovered component and you can calculate its percentage composition by mass: its mass divided by the mass of the original sample, times 100. This is the real knowscape from knowhere, not a picture of one. Drag it. Watch what actually changes.

chemistry · properties and structure of matter · separating mixtures by physical propertiesdrag it · it is yours

why this one carries the topic.

Most of this topic is one question at three zoom levels: how hard does a nucleus hold electrons? That sets periodic trends and flame colours, then which atom gets the bonding pair, then how particles cling: strength sets melting point and hardness; how charges sit is why salt shatters, copper bends.

A beaker of sand, salt and iron filings is run through three stations (a magnet, a filter funnel and an evaporating basin) and each component lands in its own dish, labelled with its recovered mass and its percentage of the original sample.

five things, not forty.

Heterogeneous mixtures, like sand, salt and iron filings, have visibly separate parts; homogeneous mixtures, like salt water, have a uniform composition throughout.

Each separation technique exploits one physical property: magnetism, particle size (filtration, sieving), solubility, density (decanting) or boiling point (evaporation, distillation).

Separation is a physical change: no new substances form, so the masses of the separated components should add back to the mass of the original sample.

Percentage composition by mass (weight) = mass of component ÷ mass of the whole sample × 100, and the percentages of all components add to 100%.

Mixtures have variable composition, so two samples of the same kind of mixture can give different percentages, while a pure compound always gives the same ones.

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this conceptseparating mixtures by physical propertiesA beaker of sand, salt and iron filings is run through three stations (a magnet, a filter funnel and an evaporating basin) and each component lands in its own dish, labelled with its recovered mass and its percentage of the original sample.

sits under itphysical properties and intermolecular forcesbecause Boiling point and solubility are the physical properties these separations rely on.

sits under itdissolution of ionic compoundsbecause Filtration splits sand from salt only because the ionic salt dissolves in water and sand does not.

9 more, same treatment.

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trends across the periodic tablelive →flame colours and electron energy levelsin the appalpha, beta and gamma decaylive →ionic versus covalent bondingin the appallotropes of carbonin the appionic, covalent and metallic structuresin the appbonds within versus forces betweenin the appprotons, neutrons and isotopesin the appelectron shells filling upin the app

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