Final answer:
To calculate the mass percent of oxygen in sodium oxide, divide the mass of oxygen by the molar mass of the compound and multiply by 100%. The mass percent of oxygen in sodium oxide is approximately 25.82%.
Step-by-step explanation:
In order to calculate the mass percent of oxygen in sodium oxide (Na2O), you need to find the mass of oxygen in the compound and divide it by the total mass of the compound. Sodium oxide consists of two sodium atoms (mass of one sodium atom = 22.990 g/mol) and one oxygen atom (mass of one oxygen atom = 15.999 g/mol). The total molar mass of sodium oxide is therefore 2 * 22.990 g/mol + 15.999 g/mol = 61.979 g/mol.
The mass of oxygen in sodium oxide is 15.999 g/mol. To calculate the mass percent, divide the mass of oxygen by the molar mass of the compound, and multiply by 100%. So, in this case, the mass percent of oxygen in sodium oxide is (15.999 g/mol / 61.979 g/mol) * 100% = 25.82% (rounded to two decimal places).