The calcium and the Calcium Oxide are divided by 2 because of their coefficients there is no number in front of the oxygen so it is over one. Hope this helped!!
Mole ratio is the ratio used to determine the equivalent of two substances (in moles) in a chemical reaction. Only the <u>number of moles</u> of a substance involved in a chemical reaction is considered in mole ratio. Also, the reaction for which mole ratio is to be considered must be balanced.
The interpretation of the equation in the question is that calcium (Ca) and oxygen (O₂) react in the ratio 2:1 to form calcium oxide (CaO).
It can also be said that 2 moles of Ca will be needed in the production of 2 moles of CaO. Hence the mole ratio between the two substances is 2:2.
The mole ratio between O₂ and CaO is 1:2 since 1 mole of O₂ was needed to produce 2 moles of CaO
