How many atoms are there in 2.50 mol of carbon dioxide? complete the response using standard scientific notation?

The answer to this question would be: 4.52 * 10^24 atoms
In this question, the carbon dioxide unit is already in mol so you don't need to find the molecular weight of the carbon dioxide. Carbon dioxide chemical formula would be CO2 which means every 1 carbon dioxide molecule is made of 3 atoms, 1 carbon atom and 2 oxygen atoms. 

Then, the number of atoms in 2.5 mol of carbon dioxide would be:
2.5 mol * 3 * 6.02 *10^23 atoms/mol =
45.15 * 10^23 =
4.52 * 10^24 atoms