How many molecules are in 24.0 grams of CO₂?

also,

How many formula units does 300.0 grams of calcium carbonate represent?

pretty confused about these, help would be greatly appreciated! :)

One mole of co2 weighs 44 grams i.e avagadro number of co2 molecules weigh 44 grams similarly 24 grams contain 24N/44 molecules of co2 i.e 6N/11 molecules where N is 6.023*10^23 a formula unit of ionic compounds is similar to a molecule in covalent compounds one mole of formula unit of CaC03 weighs 100 grams hence 300 grams contain 3N formula units