Question

4.6cm3 of methyl alcohol is dissolved in 25 .2 gm of water Calculate %/by weightof methyl alcohol.mole fraction of methyl alcohol and water

Answer 1

1) Formal for w/w %%(w/w)=wt. of solutewt. of solute+wt. of solute×100put the value:density of alcohol=0.8 g/ml so mass of 4.6 mld=massvolume; mass=0.8×4.6=3.68 g% by mass=3.683.68+25.2×100%=12.74% by mass2) mole fraction of solute =moles of solutetotal molesmoles of alcohol=wtm.wt.=3.6832=0.115moles of water=25.218=1.4mole fraction of alcohol =0.1151.515=0.0759mole fraction of water=1.41.515=0.9241.

Answer 2

Hello dear,

● Answer -
w/w % = 14.44 %
X1 = 0.925
X2 = 0.0753

● Explaination -
# Given -
W1 = 25.2 g
V2 = 4.6 cm^3

# Solution -
Mass of methyl alcohol dissolved -
W2 = d2.V2
W2 = 0.79 × 4.6
W2 = 3.64 g

Percentage by weight of methyl alcohol -
w/w % = W2 / W1
w/w % = 3.64 / 25.2
w/w % = 0.1444
w/w % = 14.44 %

Moles of H2O -
n1 = W1 / M1
n1 = 25.2 / 18
n1 = 1.4 mol


Moles of CH3OH -
n2 = W2 / M2
n2 = 3.64 / 32
n2 = 0.114 mol

Mole fraction of H2O -
X1 = n1 / (n1+n2)
X1 = 1.4 / (1.4+0.114)
X1 = 0.925

Mole fraction of CH3OH -
X2 = n2 / (n1+n2)
X2 = 0.114 / (1.4+0.114)
X2 = 0.0753

Hope this helped...