To calculate the number of carbon dioxide molecules in 10 moles of the substance, we first need to determine the molar mass of carbon dioxide.

Carbon has a molar mass of 12.01 g/mol, and oxygen has a molar mass of 16.00 g/mol. So, the molar mass of carbon dioxide (CO2) is:

12.01 g/mol + 2(16.00 g/mol) = 44.01 g/mol

Next, we need to convert the amount of substance from moles to grams, using the molar mass of carbon dioxide:

10 moles * 44.01 g/mol = 440.1 g

Now, we need to calculate the number of carbon dioxide molecules in 440.1 grams of the substance. We will use Avogadro's number, which is approximately 6.022 x 10^23 molecules/mol:

Number of molecules = (440.1 g / 44.01 g/mol) 6.022 x 10^23 molecules/mol
Number of molecules = 10 6.022 x 10^23
Number of molecules = 6.022 x 10^24

Therefore, there are approximately 6.022 x 10^24 carbon dioxide molecules in 10 moles of the substance.