Classification of Matter Worksheet – Elements to Mixtures

All 32 samples

Element 8

aluminum A light metal element, symbol Al, rolled into kitchen foil.
copper A metal element, symbol Cu, drawn into electrical wires.
diamond Carbon and nothing else. Diamond and graphite are two forms of that one element.
gold A metal element, symbol Au. It can be found pure in rocks.
helium An element, symbol He. This gas is lighter than air and fills party balloons.
iron A metal element, symbol Fe. A magnet picks it up.
oxygen A gas of the air. Its molecules are pairs of oxygen atoms, with no other atom in them.
sulfur A bright yellow solid element, symbol S.

Compound 8

ammonia NH3: nitrogen bonded to hydrogen. A colorless gas with a sharp smell.
baking soda Sodium bicarbonate, NaHCO3: four elements in one compound.
carbon dioxide CO2: carbon and oxygen, two oxygen atoms to each carbon atom.
methane CH4: carbon and hydrogen, four hydrogen atoms to each carbon atom. Natural gas is mostly methane.
quartz Silicon dioxide, SiO2: a hard mineral.
table salt Sodium chloride, NaCl: sodium and chlorine, one to one.
table sugar Sucrose, C12H22O11: carbon, hydrogen and oxygen bonded into one molecule.
water H2O: hydrogen and oxygen, two hydrogen atoms to each oxygen atom.

Show all 32 samples (16 more)

Homogeneous mixture 8

air Mostly nitrogen with oxygen and other gases spread evenly through it.
brass An alloy: copper with zinc in it.
bronze An alloy, mostly copper, usually with tin.
gasoline Many hydrocarbons blended into one even liquid.
salt water Salt dissolved in water: a solution, alike in every drop.
steel An alloy: iron with carbon in it.
sugar water The sugar dissolves and does not settle; no filter takes it out.
vinegar Acetic acid dissolved in water.

Heterogeneous mixture 8

flour in water A suspension: the flour does not dissolve, and in time it settles.
granite A rock whose grains of quartz, feldspar and mica can be told apart by eye.
gravel Loose pieces of rock.
muddy water A suspension: bits of soil hang in the water.
oil and vinegar Shaken into a dressing, the two blend for a short time, then part into layers.
oil and water Two liquids that will not blend.
sand and water The sand stays sand; a filter takes it out again.
trail mix Nuts, dried fruit and granola tossed together.

How this list was compiled: List chosen for this site on 2026-10-15. The four classes are those of the English Wikipedia article Mixture and its diagram of elements, compounds, homogeneous mixtures and heterogeneous mixtures (https://en.wikipedia.org/wiki/Mixture; Wikipedia's text is under the Creative Commons Attribution-ShareAlike license) and of BBC Bitesize, Elements, compounds and mixtures (https://www.bbc.co.uk/bitesize/articles/zngddp3). Each sample stands under one heading only and was checked that day at a page that puts it there. Elements: BBC Bitesize names oxygen, iron, sulfur, gold, copper, aluminium and helium as elements and diamond as a form of the element carbon; symbols and the color of sulfur are from the Wikipedia articles Gold, Iron, Copper, Aluminium, Helium, Sulfur, Oxygen and Diamond. Compounds: BBC Bitesize for water, carbon dioxide and table salt with their formulas; the Wikipedia articles Sodium chloride, Sucrose, Sodium bicarbonate, Methane, Ammonia and Quartz for the rest. Homogeneous mixtures: the article Mixture for salt and sugar dissolved in water, for air and for alloys as solid solutions; Vinegar, Gasoline, Brass, Bronze and Steel for what each is made of. Heterogeneous mixtures: the article Mixture for sand in water, oil and water and its table of suspensions (mud, granite, gravel, vinaigrette); Suspension (chemistry) for flour in water; Granite, Gravel, Vinaigrette and Trail mix for what each is made of. For the answers under the tool: BBC Bitesize for how a compound differs from a mixture and how mixtures are separated; the Wikipedia articles Milk and Colloid. Left out: milk, fog, smoke and blood (colloids, which the article Mixture sets apart from solutions and suspensions) and hydrogen. Licence: own work

How it works

This classification of matter worksheet prints twenty samples, among them gold, table sugar, sugar water and granite, above four headings: Element, Compound, Homogeneous mixture and Heterogeneous mixture. Pupils write each sample under its heading. A key is the last page.

Read the full guide

Pairs that look alike

The list under the tool is built from near neighbors. Table salt and table sugar are compounds; salt water and sugar water are homogeneous mixtures. Iron is an element; steel, iron with carbon in it, is a mixture. Diamond is an element, pure carbon; carbon dioxide is a compound. Oil and water is a heterogeneous mixture, and so is oil shaken with vinegar, though vinegar alone is homogeneous.

Only a sheet of 16 or 20 samples prints all four headings. Other counts print two or three of them.

Questions and answers

How is matter classified?

Matter is either a pure substance or a mixture. A pure substance is an element, one kind of atom, or a compound, elements bonded in a fixed ratio. A mixture is homogeneous, alike all through, or heterogeneous, with parts that stay apart.

What is the difference between a compound and a mixture?

In a compound the elements are bonded together, always in the same ratio, and only a chemical reaction can part them: water is always H2O. In a mixture nothing is bonded and the amounts are free: a little sand in the water, or a lot.

Is milk a homogeneous or heterogeneous mixture?

Milk looks alike all through, but it is a colloid: tiny globules of butterfat hang in a watery liquid, undissolved and far too small to see. Seen that closely it is heterogeneous. It can be argued both ways, so milk is not on the sheet.

How are mixtures separated?

By physical means, because nothing in a mixture is chemically bonded. A filter takes sand out of water. Distilling salt water boils the water off and leaves the salt behind. A magnet lifts iron filings out of sulfur powder.