"Concentration"Concentration == "Moles of solute"/"Volume of solution (L)"Moles of soluteVolume of solution (L), and thus "Concentration"Concentration has the units mol*L^-1mol⋅L−1. With this relationship we can solve most problems of dilution.
We started with 25.7*mL25.7⋅mL of a 3.12*mol*L^-13.12⋅mol⋅L−1 KMnO_4KMnO4 solution.
"Moles of "KMnO_4Moles of KMnO4 == 25.7xx10^-3*Lxx3.12*mol*L^-125.7×10−3⋅L×3.12⋅mol⋅L−1 == ??*mol??⋅mol.
This molar quantity was then diluted to a 50.00*mL50.00⋅mL volume.
"Final concentration"Final concentration == (25.7xx10^-3*cancelLxx3.12*mol*cancel(L^-1))/(50.00xx10^-3*L) = ??mol*L^-1