Question

How many moles of KNO3, should be used to prepare 0.70 L of a 0.560 M solution?

Answer 1

0.392 moles of KNO3.

Step-by-step explanation:

To find the moles of a solute based on the volume and concentration of a solution, we use the following formula:

`Molarity\text{ \lparen M\rparen=}\frac{mole\text{s of solute}}{liter\text{s of solution}}=\frac{mo\text{l }}{L}.`

The given data is: molarity = 0.560 M and volume (liters of solution) = 0.70 L. So, let's solve for 'moles of solute' and replace the values that we have. The solute in this case, would be KNO3:

`\begin{gathered} mole\text{s of solute=Molarity \lparen M\rparen}\cdot liter\text{s of solution} \\ mole\text{s of KNO}_3\text{=0.560M}\cdot0.70\text{ L = 0.392 moles KNO}_3. \end{gathered}`

We're going to use 0.392 moles of KNO3 to prepare 0.70 L of a 0.560 M solution.