Mass of this substance = 9.928 g
Further explanation
Molarity is a way to express the concentration of the solution
Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution
![\large{\boxed {\bold {M ~ = ~ \frac {n} {V}}}](https://img.qammunity.org/2021/formulas/chemistry/high-school/3y3zno44t8yfpzlz1cte5il1fifkf98njq.png)
Where
M = Molarity
n = Number of moles of solute
V = Volume of solution
So to find the number of moles can be expressed as
![\boxed{\bold{n=V* M}}](https://img.qammunity.org/2021/formulas/chemistry/college/2us87vp13xc9m5gksxj9rl3b8j80iqbaop.png)
mol of substance -Lithium nitrite - LiNO₂ :
V = 250 ml = 0.25 L
M = 0.75 M
![\tt n=0.25* 0.75=0.1875](https://img.qammunity.org/2021/formulas/chemistry/high-school/6bdmxpsyv255zhtqp0qzeznxgfoefw2s0g.png)
So mass of this substance - LiNO₂ (MW=52,947 g/mol) :
![\tt mass=mol* MW\\\\mass=0.1875* 52,947 g/mol\\\\mass=9.928~g](https://img.qammunity.org/2021/formulas/chemistry/high-school/dqigs6zf6pezag8h2tynpml3t80opm8gwh.png)