Question

How many moles of `KCI` are required to prepare 1.50 L of 5.4 M `KCl`?

Answer 1

Why `8.1` `"moles"` of potassium chloride.

Explanation:

`"Concentration"="moles of solute"/"volume of solution"`

Since the concentration was specified to be `5.4` `mol•L^(-1)`, and the volume was specified to be `1.5` `L`, the given molar quantity is appropriate for this concentration.

As a word of caution, I don't know for a moment whether potassium chloride is soluble enough to give these concentrations. Check on the web to see the solubility of potassium chloride in aqueous solution. If this question quotes an unreasonable solubility, then it was entirely inappropriate to ask.