What mass is the amount of sodium oxide substance required to obtain 37 grams of calcium?

Let’s compose and solve the proportion
CaO + H2O = CA (OH) 2
n (Ca (OH) 2) = m (Ca (OH) 2) / M (Ca (OH) 2) = 37 grams / 74 g / mol = 0.5 mol
From 1 mol of CaO, 1 mol of Ca (OH) 2 is obtained (according to the equation)
From x mol of CaO, 0.5 mol of Ca (OH) 2 will be obtained (by condition)
Hence x = 0.5 mol
m (CaO) = n (CaO) * M (CaO) = 0.5 mol * 56 g / mol = 28g
Answer: To get 37 grams of calcium you need 28 grams of sodium oxide.