Question

What is the density of an aqueous solution that is 50.0% KOH by mass and has a KOH concentration of 13.39 M?

Answer 1

To find the density of a 50.0% KOH solution with a 13.39 M concentration, multiply the molarity by the molar mass of KOH to get mass per liter, and then double it for a 50% solution by mass to obtain the density.

Step-by-step explanation:

The density of a solution that is 50.0% KOH by mass with a concentration of 13.39 M can be determined using the mass percentage, the molarity, and the molar mass of KOH. First, we calculate the mass per liter of the solution from the molarity:

Mass per liter = Molarity (M) × Molar mass (g/mol)

For KOH:

Molar mass of KOH = 39.1 (K) + 16.0 (O) + 1.0 (H) = 56.1 g/mol

Using the molarity, we find the mass per liter of the solution:

Mass per liter = 13.39 M × 56.1 g/mol = 751.449 g/L

Since 50% of the mass is KOH, we double the mass per liter to find the density:

Density = 751.449 g/L × 2 = 1502.898 g/L or 1.502898 g/cm³

Answer 2

Density = 1.56 g/mL

Step-by-step explanation:

We have two sort of concentrations in here, so let's combine them.

% by mass means grams of solute in 100 g of solution

M means, moles of solute in 1L of solution.

We know that our solute is KOH (Molar mass = 56.1 g/mol)

We convert the moles of solute to grams:

56.1 g/mol . 13.9 moles = 779.79 g

Now, we know that 50 g of solute are in 100 g of solution

Then, 779.79 g of solute will be contained in (100 . 779.79)/50 = 1559.58 g of solution

Density = mass / volume

1559.58 g of solution / 1000 mL of solution = 1.56 g/mL