Question

4.6 Cm3 of ethanol is dissolved in 25.2g of water . calculate percantage by mass of ethanol​

Answer 1

Answer:

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.

Explanation:

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