Here is how to calculate the weight percent carbon in CO2.
(Atomic Mass: C = 12.0 amu     O = 16.0 amu)

1. Find the mass of C in 1 mole of CO2.

1 x 12.0 g/mol = 12.0 grams

2. Find the total mass of 1 mole of CO2.

1 x 12.0 =	12.0 grams
2 x 16.0 =	32.0 grams
Total =	44.0 grams

3. Divide the grams of C by the gram-molecular weight and multiply by 100.

Weight % C =

12.0 g C 44.0 g CO2

x 100 = 27.3%

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