# A 5*g mass of sodium chloride, and an 8.2*g mass of sodium sulfate are dissolved in a 200*mL of aqueous solution. What is [Na^+]?

Sep 18, 2017

Well I make $\left[N {a}^{+}\right] = 1.00 \cdot m o l \cdot {L}^{-} 1$

#### Explanation:

$\text{Moles of NaCl} = \frac{5.0 \cdot g}{58.44 \cdot g \cdot m o {l}^{-} 1} = 0.0856 \cdot m o l$.

$\text{Moles of}$ $N {a}_{2} S {O}_{4} = \frac{8.2 \cdot g}{142.04 \cdot g \cdot m o {l}^{-} 1} = 0.0577 \cdot m o l$.

And thus $\left[N {a}^{+}\right] = \frac{0.0856 \cdot m o l + 2 \times 0.0577 \cdot m o l}{200 \cdot m L \times {10}^{-} 3 \cdot L \cdot m {L}^{-} 1}$

=??*mol*L^-1.

Why did I double the molar quantity with respect to $N {a}_{2} S {O}_{4}$. Did I make a mistake?