Question

HOW MANY GRAMS OF CA ARE REQUIRED IF I HAVE 12.9 GRAMS OF OXYGEN TO FORM CAO

Answer 1

Write the equation and balance it.

Convert 12.9 g O2 to mols. mols = grams/molar mass.
Use the coefficient in the balanced equation to convert mols O2 to mols Ca.
Now convert mols Ca to grams. g = mols x molar mass.
Note: All caps makes it difficult for us to read the post. Also, Co CO, and co all mean something different. CA means California to me which has little to do with the problem.