The molar mass of carbon is 12.01 g/mol. To calculate the number of moles in 4.50 g of carbon, we can use the formula:

$$moles = \frac{mass}{molar \ mass}$$

Substituting the given values into the formula, we get:

$$moles = \frac{4.50 g}{12.01 g/mol} = 0.374 \ mol$$

Therefore, there are 0.374 moles in 4.50 g of carbon.