Answer:
0,268M
Explanation:
A dilution is a process in which the concentration of a solution is reduced by adding more solvent.
In the problem, the sample of Mg(NO₃)₂ was diluted from 35,00mL to 62,50mL -dilution factor: 62,50mL/35,00mL- . The NO₃⁻ concentration of this diluted solution was 0,300M, as Mg(NO₃)₂ has two NO₃⁻, the concentration of Mg(NO₃)₂ in the diluted solution is:
0,300M NO₃⁻×[tex]\frac{1Mg(NO_{3})_2}{2NO_{3}^-}[/tex] = 0,150M Mg(NO₃)₂
Using dilution factor, the original concentration of Mg(NO₃)₂ is:
0,150M Mg(NO₃)₂×[tex]\frac{62,50mL}{35,00mL}[/tex] = 0,268M
I hope it helps!