Home
Class 12
CHEMISTRY
Calculate the molecular weight of a subs...

Calculate the molecular weight of a substance whose `7.0%` (by weight) solution in water freezes at `-0.89^(@)C`. `(k_(f) "for" H_(2)O=1.86K"molality"^(-1)`).

Text Solution

Verified by Experts

`DeltaT_(f)=K_(f)xx"Molality"=K_(f)xx(wxx1000)/(mxxW)`
w=7 g, W=100-7=93g, `DeltaT_(f)=0.89, K_(f)=1.86`
`:.` Molecular wt.,
`m=(K_(f)xxwxx1000)/(WxxDeltaT_(f))=(1.86xx7xx1000)/(93xx0.89)`
`=157.30`
Promotional Banner

Topper's Solved these Questions

  • DILUTE SOLUTION AND COLLIGATIVE PROPERTIES

    P BAHADUR|Exercise Exercise 3B Objectice Problems|1 Videos

  • DILUTE SOLUTION AND COLLIGATIVE PROPERTIES

    P BAHADUR|Exercise Exercise 9 Advanced Numerical|12 Videos

  • CHEMICAL KINETICS

    P BAHADUR|Exercise Exercise 9|13 Videos

  • ELECTROCHEMISTRY

    P BAHADUR|Exercise Exercise (9) ADVANCED NUMERICAL PROBLEMS|36 Videos

Similar Questions

Explore conceptually related problems

Calulate the molesules mass of a substance whose 7.0% by mass solution in water freezes at -0.93^(@)C . the cryosctopic constant of water is 1.86^(@)C kg mol^(-1) :

The freezing point of 0.08 molal NaHSO_(4) is -0.345^(@)C . Calculate the percentage of HSO_(4)+O ions that transfers a proton to water. Assume 100% ionization of NaHSO_(4) and K_(t) for H_(2)O = 1.86 K molality^(-1) .

Calculate the molecular weight of a substance if the freezing point of a solution containing 100 g of benzene and 0.2 g of the substance is 0.17 K below that of benzene. The cryoscope constant of benzerne is 5.16 K kgmol^(-1)

0.1 mole of sugar is dissolved in 250 g of water. The freezing point of the solution is [K_(f) "for" H_(2)O = 1.86^(@)C "molal"^(-1)]

The weight of ethyl alcohol which must be added to 1.0 L of water so that the solution will freeze at 14^@F is (K_f of water = 1.86 K kg mol^(-1) )

30 mL of 0.1M KI_(aq.) and 10 mL of 0.2M AgNO_(3) are mixed. The solution is then filtered out. Assuming that no change in total volume, the resulting solution will freezing at: [K_(f) "for" H_(2)O = 1.86K kg mol^(-1) , assume molality = molality]