Calcium oxide can be prepared by heating calcium metal in oxygen according to the reaction: 2Ca+ O(2) --> 2CaO. How many grams of calcium would be needed to produce 15.0 grams of calcium oxide?
To determine the number of grams of calcium needed to produce 15.0 grams of calcium oxide, we need to use stoichiometry and the given balanced equation.
Step 1: Write down the balanced equation:
2Ca + O₂ → 2CaO
Step 2: Calculate the molar mass of calcium oxide (CaO):
Molar mass of Ca = 40.08 g/mol
Molar mass of O = 16.00 g/mol
Molar mass of CaO = (1 × 40.08) + (1 × 16.00) = 56.08 g/mol
Step 3: Convert the given mass of CaO to moles:
moles of CaO = mass (g) / molar mass (g/mol)
moles of CaO = 15.0 g / 56.08 g/mol ≈ 0.267 mol
Step 4: Use the stoichiometry of the balanced equation to determine the number of moles of calcium required.
From the balanced equation, we know that 2 moles of Ca are required to produce 2 moles of CaO.
So, the molar ratio of Ca to CaO is 2:2 (or 1:1).
moles of Ca = moles of CaO = 0.267 mol
Step 5: Calculate the mass of calcium needed:
mass of Ca = moles of Ca × molar mass of Ca
mass of Ca = 0.267 mol × 40.08 g/mol ≈ 10.68 g
Therefore, approximately 10.68 grams of calcium would be needed to produce 15.0 grams of calcium oxide.
mols CaO = grams/molar mass.
Convert mols CaO to mols Ca using the coefficients in the balanced equation. Then g Ca = mols a x atomic mass Ca.