what is the molar concentration of an aqueous NaOH solution when 45.0 grams are dissolved in water to make 100mL of solution
Molarity=moles/volumeinliters=mass/(molmass*volumeinliters)
To find the molar concentration of an aqueous solution, we need to know the amount of solute (in moles) and the volume of the solution (in liters).
First, let's convert the mass of NaOH from grams to moles using its molar mass. The molar mass of NaOH is the sum of the atomic masses of sodium (Na), oxygen (O), and hydrogen (H).
To calculate the molar mass:
Na = 22.99 g/mol
O = 16.00 g/mol
H = 1.01 g/mol
Molar mass of NaOH = (22.99 g/mol) + (16.00 g/mol) + (1.01 g/mol) = 39.99 g/mol
Now, let's convert the mass of NaOH to moles:
45.0 g NaOH * (1 mol NaOH / 39.99 g NaOH) = 1.125 mol NaOH
Next, we need to convert the volume of the solution from milliliters (mL) to liters (L):
100 mL * (1 L / 1000 mL) = 0.1 L
Finally, we can calculate the molar concentration (often denoted as Molarity) using the formula:
Molarity (M) = moles of solute / volume of solution (in L)
Molarity = 1.125 mol NaOH / 0.1 L = 11.25 M
Therefore, the molar concentration of the aqueous NaOH solution is 11.25 M.