Determine the mass of calcium oxide, which is formed by burning 12g of calcium. Calculate the mass of oxygen reacted.

The calcium oxidation reaction is described by the following chemical reaction equation:

Ca + ½ O2 = CaO;

From 1 mole of calcium, 1 mole of calcium oxide is synthesized.

Let’s calculate the chemical amount of a substance contained in 12 grams of calcium.

M Ca = 40 grams / mol;

N Ca = 12/40 = 0.3 mol;

The same amount of calcium oxide will be obtained.

We calculate the weight of 0.3 mol of calcium oxide.

M CaO = 40 + 16 = 56 grams / mol;

m CaO = 0.3 x 56 = 16.8 grams;

0.15 mol of oxygen will enter into the reaction.

Its weight will be:

m O2 = 0.15 x 32 = 4.8 grams