1. The problem statement, all variables and given/known data How would you prepare a 500 ml lab stock of 20% (w/v) SDS That is all that is stated in the problem. 2. Relevant equations I'm assuming for w/v the volume would be 0.5L but the weight I'm not sure. 3. The attempt at a solution 0.5L x .20 = .1g SDS / .5 L .. is that correct? doesn't make sense to me. Please help!