How many grams of co2 are in 8 mol of the compound?

If you look at the periodic table, underneath each element it give you the atomic mass, which has the units g/mol.  So CO2 have a molecular mass (MM) of those combined atomic masses.  

The MM for CO2 would be...
12.01 g/mol + 2(16.00 g/mol) = 44.01 g/mol

This can be used as a conversion to change from moles to grams.

8 mol * (44.01 g / 1 mol) = 352.08 g or 6 x 10 to the 2 g for the significant figures (sig figs) at are shown in your problem.  

You may have just typed 8 instead of 8.0 or 8.00 which would change your sig figs.  It is all important to right now all your zeros, since almost all chemistry calculations involve significant figures.

I solved the above equation using dimensional analysis and had to cancel out the units, in case this is your first chemistry class.

I hope I helped!

Since there is the same amount of agn03 in both silver chloride and silver nitrate they produce the same amount of moles. therefore silver chloride produces the same amount of silver nitrate, so your answer is 15.0 moles of silver nitrate. i hope this !