Question

A student adds 5400.0mL of 0.15M NaOH to 201.2mL of 4.0M NaOH. What is the final [NaOH]?

Answer 1

Answer:

0.287 M

Explanation:

Multiply the concentration of each solution by the volume of each (in liters) to get the moles of NaOH in that solution.

0.15 M • 5.4000 L = 0.81 mol NaOH

4.0 M • 0.2012 L = 0.80 mol NaOH

Add the mol of NaOH together to get the total --> 0.81 + 0.80 = 1.61 mol NaOH

Divide by the total volume of solution (5400.0 mL + 201.2 mL = 5,601.2 mL = 5.6012 L)

1.61 mol / 5.6012 L = 0.287 M NaOH