7Ca+1O_(2)arrow ZCaO How many grams of calcium is used in this reaction, if 15.0 g calçium oxide are produced? a) 5.4g (light green) x 10.7g ( purple) b) 7.25 g k areen d) 15.0g rk blue)

## Step 1: Identify the reaction equation### The reaction is: .## Step 2: Calculate molar mass### Molar mass of Ca = 40.08 g/mol, CaO = 56.08 g/mol.## Step 3: Determine moles of CaO produced### Moles of CaO = .## Step 4: Calculate moles of Ca used### Moles of Ca needed = Moles of CaO produced = 0.2675 mol.## Step 5: Calculate mass of Ca### Mass of Ca = moles of Ca molar mass of Ca = .