concentration and dilution — VCE chemistry year 11, live

Concentration and dilution

Concentration tells you how much solute is shared out through each litre of solution: c = n ÷ V. Diluting a solution adds solvent only, so the moles of solute stay fixed while the volume grows and the concentration falls in proportion, which is why c₁V₁ = c₂V₂. The same solution can be reported in mol L⁻¹, g L⁻¹, %(m/v), %(v/v) or ppm, and converting between them is a matter of molar mass and units. This is the real knowscape from knowhere, not a picture of one. Drag it. Watch what actually changes.

chemistry · measuring and analysing chemicals · concentration and dilutiondrag it · it is yours

why this one carries the topic.

Particles are far too small to count, so every method here measures what you can (mass, volume, gas pressure, a titre, a colour) and converts it to moles. Then the balanced equation's ratio does the rest. Titration, gas laws, heating a salt to constant mass: one move.

Fifty copper(II) and sulfate ion dots sit in a container of solution. Raise the volume and the liquid rises, the same dots spread out and the colour fades, while a graph of c against V shows the concentration falling along a curve whose rectangle c × V never changes area.

five things, not forty.

Concentration is the amount of solute per volume of solution: c = n ÷ V, in mol L⁻¹, with V in litres.

The same solution can be quoted in mol L⁻¹, g L⁻¹ (mol L⁻¹ × molar mass), %(m/v) (g per 100 mL), %(v/v) (mL of liquid per 100 mL) or ppm (mg per kg, about mg L⁻¹ in water).

Dilution adds solvent only, so moles of solute before = moles after: c₁V₁ = c₂V₂, where V₂ is the final volume of solution, not the water added.

A standard solution is made by weighing a pure solid accurately, dissolving it and making it up to the mark in a volumetric flask: n = m ÷ M, then c = n ÷ V.

To dilute accurately, pipette a measured aliquot of stock into a volumetric flask and make it up to the mark with deionised water.

You can determine a concentration in the lab, for example by evaporating a measured volume to dryness and weighing the residue, or by titrating it against a standard solution.

nothing here is a standalone fact.

knowhere maps every concept to what it rests on and what rests on it — 3 underneath this one, 2 built on top. Each one says why, in a sentence, not as an arrow on a diagram.

this conceptconcentration and dilutionFifty copper(II) and sulfate ion dots sit in a container of solution.

sits under itthe molebecause Concentration counts solute in moles, so n has to make sense first.

sits under itmolar massbecause Weighing a standard and converting mol L⁻¹ to g L⁻¹ both use n = m ÷ M.

sits under itdissolution of ionic compoundsbecause The solute is drawn as separate Cu²⁺ and SO₄²⁻ ions because ionic solids dissociate.

built on itstrong versus concentrated: two different dialsbecause You need mol/L and what dilution does before you can separate concentration from strength.

built on itsolubility changing with temperaturebecause Solubility is a limit on concentration, quoted in g per 100 g or mg L⁻¹.

they don't read it. they run it.

Every HSC and VCE concept in knowhere is built like this one — mapped to your curriculum, never capped by it. Free for a week. No lock-in, cancel inside the week and pay nothing.

Free for a week, then a plan you can stop any time.

not your card? send it to whoever's is.

why this one carries the topic.

five things, not forty.

nothing here is a standalone fact.

3 more, same treatment.

they don't read it. they run it.