Question

calculate the concentration of a solution in %  by volume when 56g of water is mixed with 0.17l of  ethanol ??

Answer 1

To calculate concentration by volume, first convert into volumes.
Volume of ethanol = 0.17l
Volume of water = 56g/(1g/cm³) = 56 ml = 0.056l
(taking density of water = 1g/cm³)

Total volume of solution = 0.17 + 0.056 = 0.226l
Concentration of ethanol = $\frac{volume of ethanol in solution}{volume of total solution}$ × 100
⇒ Concentration = $\frac{0.17}{0.226}$ × 100
⇒Concentration = 75.22%

Answer 2

concentration of ethanol in % = 100 * volume of ethanol / total volume of solution
               = 100 * volume of Ethanol / [ volume of ethanol + volume of water ]
              = 100 * 170 cc / [ 170 cc + 56 cc ] = 75.22 %

      as 1 liter = 1000 cc    and   1 gm of water occupies 1 cc.