Determine the molarity of a solution formed by dissolving 4.00 moles of KBr in enough water to yield 3.00 L of solution.

Molarity (M) is the numer of moles per liter (mol/L)

Both are already given:

mol = 4.00 moles of KBr

L = 3.00 L H2O (water)

Plug them both into the equation:

4.00 mol KBr = 1.33 M KBr (1.33 because of sig figs)

3.00 L H2O