Final answer:
To identify which compound contains the greatest mass of oxygen per 1.00 g sample, one must calculate the per cent composition of oxygen in Na2O, MgO, K2O, and CaO, and then determine the mass of oxygen for each compound based on this percentage.
Step-by-step explanation:
The question asks which compound among Na2O, MgO, K2O, and CaO contains the greatest mass of oxygen in a 1.00 g sample. To answer this, one must consider the molar mass of each compound and the proportion of oxygen within that molar mass. This is a stoichiometry problem that involves calculating the per cent composition of oxygen in each compound and then determining for a 1.00 g sample how much of that mass is oxygen.
For example, if we were to calculate for Na2O, we would find the molar mass of Na2O, determine the mass of oxygen in one mole of Na2O, and then calculate what fraction of 1.00 g would be oxygen. This process is repeated for each of the given compounds. After comparing the calculated masses of oxygen for each compound, we can ascertain which compound holds the most oxygen by mass per 1.00 g sample.