Question

Calculate the molarity (M) of a solution containing 49.0 grams of H3PO4 in 500 mL of solution.

Answer 1

The molarity (M) of the H3PO4 solution = 1.0 M

Step-by-step explanation

Given:

Mass of H3PO4 = 49.0 grams

Volume of the solution = 500 mL = 500/1000 = 0.5 L

What to find:

The molarity (M) of the H3PO4 solution.

Step-by-step solution:

Step 1: Convert 49.0 grams H3PO4 to moles using the mole formula.

`Mole=\frac{Mass}{Molar\text{ }mass}`

The molar mass of H3PO4 = 97.994 g/mol

So,

`Mole=\frac{49.0\text{ }g}{97.994\text{ }g\text{/}mol}=0.50\text{ }mol`

Step 2: Calculate the molarity of the solution using the molarity formula.

`Molarity=\frac{Mole}{Volume\text{ }in\text{ }L}`

Putting mole = 0.50 mol and volume = 0.50L into the formula, we have;

`Molarity=(0.50mol)/(0.50L)=1.0\text{ }M`

The molarity (M) of the H3PO4 solution = 1.0 M