Hello! I have few questions regarding concentrations and I am really confused: 1. Task: How many cm3 of water should be added on 50 cm3 solution of glucose which has mass concentration 2 g/dm3 to get solution that has concentration 0,002 mol/dm3 ? So what happened is that I got correct result but I think its not good procedure: V1(H2O) =? V2(C6H12O6)=50cm3=0,05dm3 ϒ2(C6H12O6)=2 g/dm3 C2(C6H12O6)=0,002 mol/dm3 V1⋅ϒ1=V2⋅ϒ2 ⇒ V1=(V2⋅ϒ2) / ϒ1 ϒ1=? C2= n2 / V || n2=m2 / M2 ⇒ C2=m2 / (M2 ⋅ V ) || ϒ1 = C2 ⋅ M2 ⇒ This is what confused me. If I put all data above in this I'll get 0,36 g/dm3 and after that when I put data in formula V1 = (V2⋅ϒ2) / ϒ1 I'll get V1=0,277 dm3 = 277,78 cm3 AND THAT IS CORRECT RESULT ! BUT how come I can get mass concentration of water while using data for glucose this is what consfuses me ! If I haven't done it well can someone explain me or give me any idea please. What confuses me the most is relation of different solution and solvent I cant relate them by formulas. I am ok with these tasks : How many cm3 20% solution of HCl density ∫=1,1 g/cm3 is required for prepearing 1dm3 HCl if C=2 mol/l BUT when it comes to different solution and solvent I am stuck. Sorry for bad english its not my native language :D Thanks in advance !!!