calculation the molarity ,molality and mole fraction of ethyl alcohol in a solution of total volume 95 ml prepared by adding 50 ml of ethyl alcohol (d=0.789ml-1 )to 50 ml water (d =1gml-1)
Answers
No. of moles of ethyl alcohol =
Molar mass
Volume×density
=
46
50×0.789
=0.8576
No. of moles of water =
Molar mass
Volume×density
=
18
50×1
=2.7777
Molarity =
Vol.ofsol.in mL
No.of moles
×1000
=
95
0.8576
×1000=9.027M
Molality =
Mass of solvent in grams
No.of moles of solute
×1000
=
50
0.8576
×1000=17.152m
Mole fraction =
0.8576+2.7777
0.8576
=
3.6353
0.8576
=0.236
Explanation:
Volume of ethyl alcohal used = 50 ml
Volume of wster used = 50 ml
Total volume of solution = 100 ml
Density of ethyl alcohal = 0.789g/ml
Mass of 50 ml ethyl alcohal = 0.789 × 50 = 39.45 g
No. of moles of ethyl alcohal = 39.45/46 = 0.857
Molarity = 0.857 × 1000 /95 = 9.021 M