Final answer:
To calculate the percent by mass of oxygen in carbon monoxide (CO), divide the molar mass of oxygen (16.00 g/mol) by the molar mass of CO (28.01 g/mol) and multiply by 100 resulting in 57.12% oxygen by mass.
Step-by-step explanation:
The percent by mass of oxygen in carbon monoxide (CO) can be calculated using the molar masses of carbon and oxygen. Given that carbon has a molar mass of 12.01 g/mol and oxygen has a molar mass of 16.00 g/mol, we can determine the molar mass of CO by adding these values together, resulting in a molar mass of 28.01 g/mol for CO.
To find the percent by mass of oxygen, divide the molar mass of oxygen by the molar mass of the compound and multiply by 100. Thus, the calculation would be:
(16.00 g/mol O ÷ 28.01 g/mol CO) × 100 = 57.12%
Therefore, carbon monoxide contains 57.12% oxygen by mass.