If 58g of NaOH are dissolved in water to make a final volume of exactly 400mL, what is the molar concentration of NaOH? (The FM of NaOH = 40.0)

How do I set this up?

moles NaOH = grams/mola mass

M = moles/L

You don't

3.6 M NaOH

To find the molar concentration of NaOH, you need to calculate the number of moles of NaOH in the given mass and then divide it by the volume of the solution.

Here's how you can set up the calculation:

Step 1: Convert the given mass of NaOH from grams to moles.
Number of moles = given mass / molar mass
Given mass = 58g
Molar mass of NaOH = 40.0 g/mol

Number of moles = 58g / 40.0 g/mol

Step 2: Convert the given volume of the solution from milliliters to liters.
Volume of solution = 400mL = 400/1000 = 0.400L

Step 3: Calculate the molar concentration.
Molar concentration (M) = number of moles / volume of solution in liters
Molar concentration = (58g / 40.0 g/mol) / 0.400L

Now, you can perform the division to calculate the molar concentration of NaOH.