Here's how to calculate the moles of carbon in a 1200 gram diamond:

1. Find the molar mass of carbon:

* The molar mass of carbon is 12.011 g/mol.

2. Use the molar mass to convert grams to moles:

* Divide the mass of the diamond by the molar mass of carbon:

1200 g / 12.011 g/mol = 99.91 moles

Therefore, there are approximately 99.91 moles of carbon in a 1200 gram diamond.