Chemistry · States of Matter - Gases, Liquids and Solids

This statement directly proves they are allotropes because it shows they are two different physical forms of the same element that can be interconverted. Allotropes differ in the arrangement of atoms but are made of the same element. The ability to change from graphite to diamond under high temperature and pressure is clear evidence that both are pure carbon in different structural forms.

This statement directly proves they are allotropes because it shows they are two different physical forms of the same element that can be interconverted. Allotropes differ in the arrangement of atoms but are made of the same element. The ability to change from graphite to diamond under high temperature and pressure is clear evidence that both are pure carbon in different structural forms.

This is true for both diamond and graphite because they are both made entirely of carbon. When burned in excess oxygen, each produces CO₂. However, many different carbon-containing substances also produce CO₂ on combustion, so this fact alone doesn’t confirm they are allotropes. It only shows that carbon is the main element present.

This is a key difference between the two — graphite conducts due to its delocalized electrons, while diamond’s electrons are all involved in covalent bonds, making it an insulator. This proves they have different physical properties, but by itself it doesn’t prove they are allotropes, because substances of different elements can also have such contrasting properties.

This statement directly proves they are allotropes because it shows they are two different physical forms of the same element that can be interconverted. Allotropes differ in the arrangement of atoms but are made of the same element. The ability to change from graphite to diamond under high temperature and pressure is clear evidence that both are pure carbon in different structural forms.