Final answer:
The mass percent of oxygen in chromium(III) carbonate is calculated by using the molar masses of its constituent atoms, summing them to find the molar mass of the compound, and then determining oxygen's proportion of that total mass. The final mass percent of oxygen is 56.72%.
Step-by-step explanation:
To calculate the mass percent of oxygen in chromium(III) carbonate, or Cr2(CO3)3, you first need to determine the molar mass of the compound. Chromium(III) carbonate is made up of 2 chromium atoms, 3 carbon atoms, and 9 oxygen atoms. Using the molar masses from the periodic table (Cr = 51.996 g/mol, C = 12.01 g/mol, O = 16.00 g/mol), the molar mass of the compound can be calculated as follows:
Molar mass of Cr2(CO3)3 = (2 × 51.996) + (3 × 12.01) + (9 × 16.00) = 283.97 g/mol
Now, to find the mass percent of oxygen in the compound, multiply the total number of oxygen atoms by the molar mass of oxygen and divide by the total molar mass of the compound, then multiply by 100:
Mass percent of O = × 100 = 56.72%
Thus, the mass percent of oxygen in chromium(III) carbonate is 56.72%.