Really off topic, but I need help with converting something for my lab writeup. I just can’t seem to calculate this without seeing an example of it.

Q: Calculate the concentration (mg/mL) of DNA using an extinction coefficient of 250 (for a 1% solution (weight/volume), a light path of 1.0cm, and a wavelength of 260.

A: Absorbance at 260 was 0.657, and the equation is:

C=Abs/ext coeff*pathlength

Seems easy enough, but the answer comes out in mol/L, I got 0.002628 mol/L, and now need to convert it to mg/mL. I know this has something to do with the 1% solution, but i don’t know how to do it. Anyone else know???