Final answer:
To find the mass of oxygen released during the decomposition of magnesium oxide, subtract the mass of magnesium (9.72 g) from the mass of magnesium oxide (16.12 g), resulting in 6.40 g of oxygen gas.
Step-by-step explanation:
To determine the mass of oxygen gas released in the decomposition of magnesium oxide, we can apply the law of conservation of mass. Since the mass of the reactants in a chemical reaction must equal the mass of the products, we can subtract the mass of magnesium from the mass of magnesium oxide to find the mass of oxygen released.
The mass of magnesium oxide given is 16.12 g, and it decomposes to form 9.72 g of magnesium. Using these quantities, we calculate the mass of oxygen as follows:
Mass of oxygen = Mass of magnesium oxide - Mass of magnesium
Mass of oxygen = 16.12 g - 9.72 g
Mass of oxygen = 6.40 g
Therefore, 6.40 g of oxygen gas is released during the decomposition of magnesium oxide.