# What is the molality of a 56*g mass of common salt dissolved in 18*mL of water?

May 23, 2016

$\text{Molality}$ $=$ $\text{Moles of solute"/"Kilograms of solvent}$ $=$ $\text{A somewhat"/" large value}$

#### Explanation:

$\text{Molality}$ $=$ $\frac{1 \cdot m o l}{0.018 \cdot k g}$ $=$ $55.6 \cdot m o l \cdot k {g}^{-} 1$.

I do not believe that a concentration this strong is physically realistic.

5.56 m

#### Explanation:

Let's assume we have 1 mole of NaCl and 1 mole of water.

Molality is calculated by dividing the moles of solute (NaCl) by the volume in L of the solvent (water)

The trick here is to figure out how much water you have.

The molar mass of water is 18g/mol.
Since the density of water is 1g/mL, 1 mole of water would have a volume of 18mL or 0.18L.

So molality of this would be

Molality = 1 mole NaCl / 0.18L water

5.56 m NaCl

Here is another lesson about calculating molality.

Hope this helps!