How many moles of Oxygen are in 1 mile of CaCo3?

The compound given in the question is which is called Calcium Carbonate. A 1 mole of Calcium Carbonate has,

1 Moles of Calcium.

1 Moles of Carbon.

3 Moles of Oxygen.

In the Question, It is asked that how many moles are present in the 1 mole of Calcium Carbonate, So as per information we have, there are 3 moles of oxygen present in Calcium Carbonate.

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Much simpler way to understand why there are 3 mole is look at the subscript along the element. There is no number in the subscript of Calcium and Carbon thus 1 Mole, There is 3 present in the subscript thus 3 moles of calcium. Remember that subscript suggests the number of moles of an element in only 1 MOLE OF COMPOUND

trigonal pyramidal

tetrahedral

trigonal planar

bent