Answer:Okay, so first, let's turn the grams into moles.
1.3 g C / 12.011 g/mol = 0.1082341187 mol C
Next, we need to multiply it by Avogadro's Number for the number of atoms.
0.1082341187 mol C * 6.022*10^23 mol^-1 = 6.51785863*10^22 atoms C
Now we take significant figures into consideration. We started with two, so we need to end it with two.
6.5*10^22 atoms C
Step-by-step explanation: