how can u answer and prepare this

1-A stock bottle of copped sulohate (heptahydydrate) is orovided. there is a mass concentration of 20%w/v and 500ml vume of copper sulphate to be prepared. using a volumetric flask, make up this solution and measure its absorbance in a spectrophotometer.

b-if the Mr of copper sulphate is 249.68. what is the molar concentration of the solution you prepared.