text: i have a concentration of 50 micromolar of  "x" solution and i want to make a 100 nanomolar conentration of it how do i got about doin that? in practice, a lot will depend on the available volumetric glassware and microvolume measuring and dispensing devices (pipettes).    let c1 = initial concentration (50 micromolar)  let v1 = the volume you want to dilute with (could be all of your 50 micromolar solution or only a part of it)  let c2 = the final concentration (100 nm or 0.1 micromolar)  let v2 = the volume you want to dilute to (the final volume you want to end up with)   the equation is c1 x v1 = c2 x v2 (we must conserve mass)  you'll have to choose either v1 or v2, then solve for the other one.