1. Find the molar mass of CO:

* Carbon (C) has a molar mass of 12.01 g/mol

* Oxygen (O) has a molar mass of 16.00 g/mol

* Molar mass of CO = 12.01 g/mol + 16.00 g/mol = 28.01 g/mol

2. Use the following formula to calculate moles:

* moles = mass / molar mass

3. Plug in the values:

* moles = 1.23 g / 28.01 g/mol

* moles ≈ 0.0439 mol

Therefore, there are approximately 0.0439 moles of CO in 1.23 g.