2 Answers

Randy Stauner · Answer 1 · 2021-09-28T15:24:21+0000

Answer:

Approximately
$0.47\; \rm mol \cdot L^(-1)$ (note that
$1\; \rm M = 1 \; \rm mol \cdot L^(-1)$ .)

Step-by-step explanation:

The molarity of a solution gives the number of moles of solute in each unit volume of the solution. In this
$\rm NaNO_3$ solution in water,

Let
be the number of moles of the solute in the whole solution. Let
represent the volume of that solution. The formula for the molarity
of that solution is:

$\displaystyle c = (n)/(V)$ .

In this question, the volume of the solution is known to be
$1250\; \rm mL$ . That's
$1.250\; \rm L$ in standard units. What needs to be found is
, the number of moles of
$\rm NaNO_3$ in that solution.

The molar mass (formula mass) of a compound gives the mass of each mole of units of this compound. For example, the molar mass of
$\rm NaNO_3$ is
$85\; \rm g \cdot mol^(-1)$ means that the mass of one mole of

$\displaystyle n = (m)/(M)$ .

For this question,

$\begin{aligned}&n\left(\mathrm{NaNO_3}\right) \\ &= \frac{m\left(\mathrm{NaNO_3}\right)}{M\left(\mathrm{NaNO_3}\right)}\\&= (50\; \rm g)/(85\; \rm g \cdot mol^(-1)) \\& \approx 0.588235\; \rm mol\end{aligned}$ .