Physical Change vs Chemical Change

[Arjun Sharma 1D]

Is the conversion of graphite to diamond a physical change or a chemical change?

[jillian1k]

It's a chemical change because there is a change in bonding that changes the identity/chemical composition of the substance. In graphite, each carbon atom is bonded to 3 other carbon atoms with one lone electron pair. Whereas in diamond, each carbon atom is bonded to the most number of carbons possible (4) with no lone electron pairs. This results in stronger, more stable bonds in diamond than in graphite.

Physical changes of substances just change the form (ie phase changes), but not the chemical composition of the substance.

[Shanmitha Arun 1L]

Graphite and diamond are both large molecules made of carbon, but have different connectivity. The carbon in graphite are bonded to 3 other carbon neighbors, but in diamond carbon bonds with 4 neighbors. Therefore, it would be a chemical change.