The concentration of sodium chloride in an aqueous solution that is 2.23 M and that has a density of
1)01 g/mL is _% by mass.
A) 45.3
B) 7.83
C) 12.9
D) 10.1
E) 2.21

Question

Quizplus · Accepted Answer

To calculate the percent by mass we first need to find the mass of the solution.

Mass of solution = volume of solution x density
Assuming we have 1 L of solution: 
= 1000 mL x 1.01 g/mL
= 1010 g

Now we need to find the mass of sodium chloride in the solution. To do this, we use the formula:

mass = concentration x volume x molar mass

The molar mass of sodium chloride is 58.44 g/mol. 
The volume of our solution is 1 L. 
The concentration of sodium chloride is 2.23 M.

mass = 2.23 mol/L x 1 L x 58.44 g/mol 
= 130.64 g

Now we can calculate the percent by mass:

% by mass = (mass of solute / mass of solution) x 100% 
= (130.64 g / 1010 g) x 100% 
= 12.9%

Therefore, the answer is C) 12.9.

The Concentration of Sodium Chloride in an Aqueous Solution That