# 40g of NaOH is added to water to create 1 L of solution. The resulting solution has a SG of 1.07. a) Calculate the mass (in lb) of 1 L of solution? b) Calculate the molecular mass of NaOH? c) Calculate the molarity of NaOH in the solution.?

Oct 16, 2017

We know that the density of the solution, ${\rho}_{\text{solution}} = 1.07 \cdot g \cdot m {L}^{-} 1$

#### Explanation:

$a .$ And so if we gots a $1 \cdot L$ volume....then we have a mass of.....

$1000 \cdot m L \times 1.07 \cdot g \cdot m {L}^{-} 1 = 1070 \cdot g$..

But $1 \cdot l b \equiv 454 \cdot g$...

And so $1070 \cdot g \equiv 1070 \cdot g \times \frac{1}{454 \cdot g \cdot l {b}^{-} 1} = 2.36 \cdot \frac{1}{l {b}^{-} 1}$ $= 2.36 \cdot \frac{1}{\frac{1}{l b}} = 2.36 \cdot l b$

$b .$ And the molar mass of $N a O H$ is simply....

$\left(22.99 + 15.999 + 1.00794\right) \cdot g \cdot m o {l}^{-} 1 = 40.0 \cdot g \cdot m o {l}^{-} 1$.

$c .$ And the molarity is simply the quotient....

$\text{Molarity"="Moles of solute"/"Volume of solution}$

$= \frac{\frac{40 \cdot g}{40.0 \cdot g \cdot m o {l}^{-} 1}}{1.00 \cdot L} = 1.00 \cdot m o l \cdot {L}^{-} 1$.....

I don't know why the septic tanks don't go back to using pounds, shillings, and pence if they are bent upon using $\text{lbs}$, and $\text{inches}$, and $\text{tons}$. And while they are at it, they could recognize Queen Elizabeth II as their lawful sovereign.