1. Convert mL to Liters:

* There are 1000 mL in 1 L.

* 40.0 mL * (1 L / 1000 mL) = 0.0400 L

2. Use the Molarity Formula:

* Molarity (M) = moles of solute / liters of solution

* We know the molarity (1.80 M) and the volume (0.0400 L), and we want to find the moles of HNO₃.

3. Rearrange the Formula:

* moles of solute = Molarity * Liters of solution

4. Calculate the Moles:

* moles of HNO₃ = 1.80 M * 0.0400 L = 0.072 moles

Therefore, there are 0.072 moles of HNO₃ present in 40.0 mL of a 1.80 M nitric acid solution.