Question

if 4 g of naoh dissolves in 36 g of h2o, calculate the mole fraction of each component in the solution. also, determine the molarity of solution (specific gravity of solution is 1g ml-1).

Answer 1

Answer: X solute = 0.048, X solvent = 0.95, M = 0.058M

Step-by-step explanation:

First, convert g to mol using the molar masses of NaOH (39.997g/mol) and H₂O(18.01g/mol):

4g NaOH (1 mol NaOH/39.997g NaOH) = 0.100 mol NaOH/solute

36g H₂O (1 mol H₂O/18.01g H₂O) = 2.00 mol H₂O/solvent

Now, add mol NaOH and mol H₂O together to get the total number of moles of solution:

0.100 mol NaOH + 2.00 mol H₂O = 2.10 mol solution

Now, we find the mole fractions of NaOH and H₂O by dividing the number of moles of the component by the total number of moles of the solution:

X solute = 0.100 mol NaOH/2.10 mol soln
= 0.048

X solvent = 2.00 mol H₂O/2.10 mol soln
= 0.95

Now, we determine the molarity of the solution by first finding the amount of solution used in mL; we are given 1g/mL, so the number of grams is equivalent to the number of mL:

36g = 36mL H₂O

Now, to determine the molarity of the solution, we divide the number of moles of solution by the mL of solution:

M soln = 2.10 mol soln/36mL H₂O

= 0.058M soln

I hope this helps! :)