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The mole fraction of CO2 in a certain solution with H2O as the solvent is 3.6 × 10−4. What is the approximate molality of CO2 in this solution? A.0.00036 m.B.0.0065 m.C.0.020 m.D.2.0 × 10−5 m.E.6.5 m

User Bhavik
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1 Answer

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Answer: C) 0.020 m

Step-by-step explanation:

Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.


Molality=(n* 1000)/(W_s)

where,

n = moles of solute


W_s = weight of solvent in g

Mole fraction of
CO_2 is =
3.6* 10^(-4) i.e.
3.6* 10^(-4) moles of
CO_2 is present in 1 mole of solution.

Moles of solute
(CO_2) =
3.6* 10^(-4)

moles of solvent (water) = 1 -
3.6* 10^(-4) = 0.99

weight of solvent =
moles* {\text {Molar mass}}=0.99* 18=17.82g

Molality =
(3.6* 10^(-4)* 1000)/(17.82g)=0.020

Thus approximate molality of
CO_2 in this solution is 0.020 m

User Corashina
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