Answer:
Step-by-step explanation: First, convert the mass of graphite from milligrams (mg) to grams (g).
As 1,000 milligrams in 1 gram
therefore,
300 mg = 300/1000 = 0.3 grams
Now, we can use the molar mass of carbon to calculate the number of moles. We divide the mass of the sample by the molar mass:
Number of moles = Mass (g) / Molar mass (g/mol)
Number of moles = 0.3 g / 12.01 g/mol
Number of moles ≈ 0.02498 moles (rounded to five decimal places)
Therefore, there are approximately 0.02498 moles of carbon in 300 mg of graphite.