Final answer:
To make a 1.35 L solution, 0.189 mol of sodium hydroxide (NaOH) is required.
Step-by-step explanation:
To find the number of moles of sodium hydroxide (NaOH) required to make a 1.35 L solution, we first need to determine the concentration of the solution in mol · dm-3. Given that 3.5 g of NaOH is dissolved in 2.5 dm3 of water, we can calculate the concentration using the formula:
Concentration (mol · dm-3) = moles of solute / volume of solution (dm3)
Concentration = (3.5 g / 39.997 g/mol) / 2.5 dm3 = 0.14 mol · dm-3
Now, to find the number of moles of NaOH required for a 1.35 L solution, we can use the formula:
Moles of solute = concentration · volume (L)
Moles of NaOH = 0.14 mol · dm-3 × 1.35 L = 0.189 mol