Respuesta :
Answer:
a) 20.65%
b) 21.73%
c) 2.15 M
Explanation:
The mass conservation law in preparation or dilution of solutions, explains that the number of moles/mass of solute does not change after adding more solvent to dilute or removing more solvent to concentrate the solution.
The total volume of solution = 15.0 mL = 0.015 L
The total weight of solution = 15.78 g
The weight of the solute = 3.26 g.
The number of moles of KNO₃ = mass/molar mass of KNO₃
Molar mass of KNO₃ = 101.10 g/mol
Number of moles = 3.26/101.1 = 0.0322 mole
a) The weight percent in (%m/m) = 3.26/15.78 = 0.2065 = 20.65%.
b) The weight percent in (%mass/volume) = 3.26/15.0 = 0.2173 = 21.73%.
c) Molarity (mol/volume in L) = 0.0322/0.015= 2.15 M
Explanation:
A. % (m/m)
Mass of KNO3 solution = mass of water + mass of dry KNO3
%(m/m) = (mass of KNO3/total mass of KNO3 solution) * 100
= (3.26/15.78) * 100
= 20.66 %
B. %(m/v)
%(m/v) = (mass of dry KNO3/volume of KNO3 solution) * 100
= 3.26/15 * 100
= 21.73 %
C. molarity
Molar mass of KNO3 = 39 + 14 + (3*16)
= 101 g/mol
Number of moles = mass/molar mass
= 3.26/101
= 0.0323 mol.
Molarity is defined as the number of moles of the solute per unit volume of solution.
Molarity = 0.0323/0.015
= 2.15 M.
