Question

calculate the mole fraction of benzene (C6H6) in solution which is 30% by mass in CCl4

Answer 1

Hey friend, ☺️ here is your answer _____________________________

30 % by mass means that 30 g of solute is dissolved in 100 g of solution or 70 g of solvent.

Now from this, we get the given mass of solute, solvent and solution.

Solute = benzene ( C6H6)
Solvent = carbon tetrachloride = CCl4

Molar mass of benzene = 12 × 6 + 1 × 6 = 72 + 6 = 78 g
Molar mass of CCl4 = 12 + 4 × 35.5 = 154 g

As we know the formula that
Number of moles = given mass / molar mass

Number of moles of benzene = 30g / 78 g = 0.38
Number of moles of CCl4 = 70g / 154 g = 0.45

Mole fraction = number of moles of solute / number of moles of solute + number of moles of solvent = 0.38 / (0.38 + 0.45) = 0.38 / 0.83 = 0.45


So, 0.45 is the mole fraction

Hope this helps you...

Answer 2

Let the total mass of the solution be 100g
Let the mass of benzene be 30g

Mass of carbon tetrachloride = total mass - mass of benzene
= (100-30)g
= 70g

Molar mass of C6H6 = 6×12+6×1
= 78g mol ^-1


By using the formula we have

No.of moles = mass / molar mass

No.of moles of C6H6 = 30/78 = 0.3846 mol

Molar mass of CCI4 = 1×12+4×335= 154g mol^-1

Using the same formula we have

Molar fraction of compound= no.of moles of component / total no.of moles

Mole fraction of benzene = 0.3846 / ( 0.3846+0.4545) = 0.458

HOPE THIS HELPS........

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