Question

Calculations of if 50ml of ethanol(density 0.79g/ml)is dissolved by 400ml of water.what is the concentration of ethanol in this solution.

Answer 1

Answer:

The concentration of 50mL ethanol in 400mL water is 2.14M.

Explanation:

given that,

     volume of solution = 400mL=0.4L

     volume of ethanol = 50 mL

     density of ethanol = 0.79g/mL

then,

   mass of ethanol = volume × density = 50 × 0.79 = 39.5g

   molar mass of CH₃CH₂OH = 12×2 + 1×6 + 16 = 46g/mol

   moles of ethanol = mass /molar mass = 39.5 / 46 = 0.858mol.

the concentration of aqueous solution of ethanol is given by,

Molarity = number of moles of solute / liters of solution

⇒           = 0.858 / 0.4 = 2.14 M