Determine the mass of calcium oxide if it is known that 80 g of calcium entered the reaction?

Given:
m (Ca) = 80 g
To find:
m (CaO) =?
Decision:
1) We draw up the equation of the chemical reaction, let the mass of calcium oxide be x g.
2Ca + O2 = 2CaO
2) Find the molecular weights of calcium and calcium oxide.
M (Ca) = 40 x 2 = 80 g / mol
M (CaO) = (40 + 16) x 2 = 112 g / mol.
3) 80 g: 80 g / mol = x g: 112 g / mol
x = (80 x 80): 112 = 112 g.
Answer: m (CaO) = 112 g.