Final answer:
The mass of oxygen gas produced after heating 15.8 g of potassium permanganate and obtaining 14.2 g of remaining material is 1.6 g. The mass of oxygen gas is determined by subtracting the post-reaction mass from the pre-reaction mass.
Step-by-step explanation:
The student has conducted a thermal decomposition reaction by heating potassium permanganate (KMnO₄) where the products are manganese dioxide (MnO₂), oxygen gas (O₂), and potassium manganate (K₂MnO₄). The mass of oxygen gas produced in the reaction can be calculated by using the law of conservation of mass.
Initially, 15.8 g of potassium permanganate was available and after heating and the release of oxygen gas, the remaining mass is 14.2 grams. The mass of oxygen gas produced can be found by subtracting the final mass of the remaining potassium permanganate from the initial mass.
Mass of oxygen gas = Initial mass of KMnO₄ - Final mass of remaining material
Mass of oxygen gas = 15.8 g - 14.2 g = 1.6 g
Therefore, the answer to the question is a) 1.6 g of oxygen gas was produced in the reaction.