How many grams are in 5.66 mol of CaCO3

First, find the molecular weight of CaCO3. Do that by locating the atomic weight of oxygen, carbon, and oxygen. Multiply those numbers by the number of atoms in the molecule (as written). Then, add the values together to get the molecular weight. The molecular weight is expressed in grams / mole. If you have 5.66 moles of a substance then you can calculate the number of grams from the molecular weight.

Note that (\frac{x}{y}) (y) = x . Substitute "x" = grams and "y" = "mole" and you can multiply the "units". The "mole" unit will cancel out and you're left with grams.