im really confused on how to do this

sorry that was one part in how to solve table 4 which is the question i need help with

so i pretty much just need to know how to find the concentration(m)

Pait A Dilution Calculations 1. Use the actual mass of mekel (II) nitrate hexahydrate you used to calculate the concentration of your stock solution. Actuarmoss=0.249g Table 4: Concentration and absorbance of stock solutions