10ml of C2H5OH(density=0.7893g/ml) and 20ml of water(density=0.0997g/ml) are mixed to get a solution. The density of the resultant solution is 0.957g/ml. Calulate the molarity of the resultant solution.
Answers
Mass = Volume × Density
Mass of C₂H₅OH = 10 mL × 0.7893 g/mL
Mass = 7.893 grams
Mass of H₂O = 20 mL × 0.0997 g/mL
Mass = 1.994 grams
Total Mass of mixture = 7.893 g + 1.994 g
Total Mass = 9.887 gram
Volume = Mass/Density
Volume of mixture = 10 mL + 20 mL = 30 mL
Moles of C₂H₅OH = 7.893/(24 + 5 + 16 + 1)
Moles = 0.2 (approx)
Moles of Water = 1.994/(2 + 16)
Moles = 0.1 (approx)
Molarity = Moles/V of Soln (in mL) × 1000
→ Molarity of C₂H₅OH = 0.2/30 × 1000 = 6.7 M
→ Molarity of Water = 0.1/30 × 1000 = 3.3 M
→ M₁v₁ + M₂v₂ = M₃v₃
→ 6.7 × 10 + 3.3 × 20 = M × 30
→ 67 + 66 = 30 M
→ 4422/30 = M
→ 147.4 M = Molarity of Solution
Molarity of Mixture is 147.4 M
Answer:
5.71 M
Explanation:
Given,
Volume of C2H5OH(ethanol) = 10ml
Density of Ethanol = 0.7897 g/ml
Molar Mass of Ethanol = 24 + 5 + 16 + 1
= 46
We know that ,
Mass = Volume × Density
Mass = 10 × 0.7893
Mass = 7.893 g
Moles of Ethanol = Mass/Molar mass
= 7.893/46
= 0.171587 Moles.
Total Volume of solution = 10ml + 20ml
= 30ml
Now, We know that Molarity,
M = (Moles of Solute/Volume of Solution)×1000
M = (0.171587/30) × 1000
M = 5.71 M
Thus Molarity of the solution is 5.71 M