Question

Calculate the molarity of a solution made by adding 250.0 mL of water to 85.00 mL of a 0.157 M solution.

Answer 1

Answer:

0.0398 mol·L⁻¹

Explanation:

You are diluting the solution with water, so you can use the dilution formula

$c_{1}V_{1} = c_{2} V_{2}$

You can solve this equation to get

$c_{2} = c_{1} \times \frac{V_{1}}{V_{2}}$  

$c_{1} = \text{0.157 mol/L}; V_{1} = \text{85.00 mL}$

$c_{2} = ?; V_{2} = \text{85.00 mL + 250.0 mL} = \text{335.0 mL}$  

$c_{2} = \text{0.157 mol/L} \times \frac{\text{85.00 mL}}{ \text{335.0 mL}} = \text{0.0398 mol/L}$