The moles of NaOH can be calculated using the formula:
moles = concentration (M) x volume (L)
First, convert the volume from milliliters to liters:
30.0 mL = 30.0 mL / 1000 mL/L = 0.03 L
Then, use the formula to calculate the moles:
moles = 3 M x 0.03 L = 0.09 moles
So, 0.09 moles of 3 M NaOH were used.