Answer: The percent by mass of oxygen in the compound CO2 is approximately 72.72%.
Step-by-step explanation:
To calculate the percent by mass of oxygen in a compound, you need to know the formula of the compound and the atomic mass of each element present.
Here are the steps to follow:
1. Write down the formula of the compound. For example, let's consider the compound CO2.
2. Find the atomic mass of each element in the compound. The atomic mass of carbon (C) is approximately 12.01 grams per mole, and the atomic mass of oxygen (O) is approximately 16.00 grams per mole.
3. Calculate the molar mass of the compound by adding up the atomic masses of all the elements present. In our example, the molar mass of CO2 would be 12.01 + (2 * 16.00) = 44.01 grams per mole.
4. Determine the mass of oxygen in the compound. In our example, the mass of oxygen in CO2 is 2 * 16.00 = 32.00 grams.
5. Finally, calculate the percent by mass of oxygen by dividing the mass of oxygen by the molar mass of the compound and multiplying by 100. Using our example, the percent by mass of oxygen in CO2 would be (32.00 / 44.01) * 100 = 72.72%.
So, the percent by mass of oxygen in the compound CO2 is approximately 72.72%.