How Much K2SO4 Solution is Needed for a Specific Potassium Ion Concentration?

[grumpyasian]

Homework Statement

Want to prepare 450.0 mL of a 145 ppm K + ion solution. density of solution is 1.01 g/mL. solution is .728 M in K2SO4. How many mL of the K2SO4 solution need to use?

Homework Equations

The Attempt at a Solution

(.728 mol/L K2SO4 )(1.01g/mL)(450.0 mL)

i don't know what to do next...help?

 

[Borek]

This is a simple mass conservation.

How much potassium will be present in the final solution?

What volume of the starting solution contains this amount of potassium?