Answer:
m = 2.955x10⁻² mol/kg
X = 5.323x10⁻⁴ mol NaCl/Total moles
(w/w)% = 0.1726%
ppm = 1726 mg/kg
Explanation:
Molality is the ratio between moles of solute per kg of solution.
As the solution is 2.950×10⁻² mol/L, mililters are 999.2mL and density is 0.9982 g/mL, molality is:
m = 2.950×10⁻² mol/L×(1L/0.9982kg) = <em>2.955x10⁻² mol/kg</em>
Mole fraction is moles of NaCl/total moles.
Moles of H₂O are:
999.2mL×(0.9982g/mL)×(1mol/18,02g) = 55,35 moles of H₂O
Moles of NaCl are:
2.950×10⁻² mol/L×(0.9992L)= 2.950×10⁻² mol of NaCl
mole fraction is:
X = 2.950×10⁻² mol of NaCl / (2.950×10⁻² mol of NaCl+55.35mol water) = <em>5.323x10⁻⁴ mol NaCl/Total moles</em>
Mass of NaCl is:
2.950×10⁻² mol of NaCl×(58.44g/mol) = 1.724g of NaCl
Mass of water is:
55.35mol water×(18.02g/mol) = 997.4g of H₂O
(w/w)% is:
1.724g of NaCl / (1.724g of NaCl+997.4g of H₂O) ×100 = <em>0,1726%</em>
<em></em>
Parts per million is mg of NaCl per kg of solution, that is:
1724mg of NaCl / 0.999124g = <em>1726 ppm</em>
<em></em>
I hope it helps!
