Respuesta :
Answer:
Mole fraction of salt is 0.00049.
The concentration of the salt solution in percent by mass is 0.16%.
The concentration of the salt solution in parts per million is 1,610.18 .
Explanation:
Molarity of the NaCl solution = [tex]2.750\times 10^{-2} M[/tex]
Moles of NaCl = [tex]n_2[/tex]
Volume of the solution = 1.000 L
Molarity=[tex]\frac{\text{Moles of compound}}{\text{Volume of solution(L)}}[/tex]
[tex]2.750\times 10^{-2} M=\frac{n_1}{1 L}[/tex]
[tex]n_1=2.750\times 10^{-2} mol[/tex]
Mass of [tex]2.750\times 10^{-2} mol[/tex] of NaCl :
[tex]2.750\times 10^{-2} mol\times 58.5 g/mol=1.60875 g[/tex]
Mass of water = m
Density of water = 0.9982 g/mL
Volume of water = 999.3 mL
[tex]Mass=Density\times Volume [/tex]
[tex]m=0.9982 g/mL\times 999.3 mL=997.50 g[/tex]
Moles of water =[tex]n_1=\frac{997.5 g}{18 g/mol}=55.416 mol[/tex]
Mole fraction of salt = [tex]\chi_1[/tex]
[tex]\chi_1=\frac{n_1}{n_1+n_2}=\frac{2.750\times 10^{-2} mol}{2.750\times 10^{-2} mol+55.416 mol}=0.00049[/tex]
Percentage by mass:
[tex]\frac{\text{Mass of Solute}}{\text{Mass of Solution}}\times 100[/tex]
[tex]\frac{1.60875 g}{1.60875 g+997.50 g}\times =0.16\%[/tex]
The concentration of the salt solution in percent by mass is 0.16%.
The concentration of the salt solution in parts per million.
[tex]=\frac{\text{Mass of solute}}{\text{Mass of solution(mL)}}\times 10^6[/tex]
[tex]\frac{1.60875 g}{1.60875 g+997.50 g}\times 10^6=1,610.18 ppm[/tex]
