Forms of carbon: diamond, graphite and coal
Test twelve substances, from diamond and graphite to charcoal, soot and sugar, for hardness, electricity and what they are made of. Sort them into crystalline carbon, amorphous carbon and carbon compounds.
Core concept
Pure carbon exists in different forms called allotropes: crystalline ones (diamond, graphite, fullerene, graphene) have their atoms in a regular pattern, amorphous ones (coal, charcoal, coke, lampblack) do not; carbon compounds such as methane and sugar contain other elements too
Topic: Carbon and its compounds
Carbon is a very special element: it is in every living thing, in fuels, and in the pencil in your bag. Pure carbon comes in several forms, called allotropes, that are made of the same atoms joined in different ways. In crystalline allotropes the atoms are in a regular pattern. In diamond each atom is joined to four others in a strong 3-D network, so it is the hardest natural substance. In graphite the atoms form flat layers that slide over each other, so it is soft and conducts electricity. Fullerene is a ball of 60 atoms and graphene a single layer. In amorphous carbon, such as coal, charcoal, coke and lampblack (soot), the atoms have no regular pattern. Carbon also joins other elements to make compounds: organic ones like methane and sugar, and inorganic ones like carbon dioxide: A gas we breathe out. Plants take it in to make their food. All key words and limestone.
What you will learn
- Define allotropy and name the allotropes of carbon.
- Explain the properties of diamond and graphite from their structures.
- Distinguish crystalline and amorphous forms of carbon.
- Distinguish pure carbon from carbon compounds, organic and inorganic.
Before you start
- Know that an element is made of only one kind of atom.
Materials
- A pencil, a piece of charcoal, sugar, a candle (for soot), a piece of limestone
Equipment
- A battery, a bulb and wires to test for electricity
Procedure
- Pick a substance's card and test it.
- Do this for at least eight substances.
- Sort every substance into crystalline carbon, amorphous carbon or a carbon compound.