Chemistry, asked by selena17, 1 year ago

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Answered by kvnmurty
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Q8.  Graham's Diffusion (Effusion) Law.

  We know a mole of ideal gas occupies 22.4 L at STP.
  1.12 L of H2 at STP contains  1.12/22.4 = 0.05 moles  (0.10 gms)
  1.12 L of D2 at STP contains  1.12/22.4 = 0.05 moles of D2  (0.20 gms)

Molar mass of H2 = 2.    Molar mass of D2 = 4
Gases H2 and D2 diffuse (effuse) into 2nd bulb, at rates r1 and r2 respectively.

       r1 / r2 = √(4/2)          =>       r1 = √2 * r2

=> number of moles of H2 in bulb2 will be √2 times number of moles of D2.

Number of moles of H2 remaining in bulb1 = 0.05 gm / (2gm/mol) = 0.025
So number of moles of H2 that diffused into bulb2 = 0.05 - 0.025 = 0.025

So number of moles of D2 that diffused into bulb2 = 0.025/√2 = 

Weight of D2 in bulb2 = 0.025/√2  * 4 = 0.05 √2 gms

Total weight of gases in bulb2:  0.025 * 2 + 0.05 √2 = 0.05 *(1+√2) gm

Composition of H2 in bulb2 = 0.05/[ 0.05(1+√2)] * 100
      = 100/(1+√2)  % = (√2-1)*100 = 41.4%  by weight

Composition of D2 in bulb2:   √2 /(1+√2) = (2-√2)*100 %   by weight
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Q9. 

Compressibility Factor = Z
    Z = Volume of real gas / Volume of Ideal gas , at same T & P.
    Z = P*V/(n R T)

     => Real Volume = V = nRT * Z / P

V1 = Real Volume of N2 of n moles at T1 = 223K, P1 = 800 atm 
V2 = Real Volume of N2  of n moles at T2 =373K, P2 = 200 atm.
Z1 = 1.95.     Z2 = 1.10.

     V2/V1 = [ T2 Z2 P1 ] / [T1 Z1 P2 ]
                = [ 373* 1.10 * 800 ] / [223 * 1.95 * 200 ]
                = 3.43 
     
Given at T=223 K and P=800 atm , V1 = 1.0 dm³
So Volume of same quantity of N2 at  P = 200 atm and 373K
            = 3.43 * 1 dm³ = 3.43 dm³

====================
Q10.   Graham's diffusion law:
 
Assume the mixture of H2 and Gas G to be Ideal.  Find the number n of moles in it.

                         P * V = n R T
            6 atm * 3 Litre = n * 8.314 J/°K/mol * (273+27)°K
            n = 6*1.013*10⁵ * 3 * 10⁻³ / [ 8.314 * 300°K]
                = 0.731 moles.

Number of moles of H2 = 0.7 moles.
Hence the number of moles of Gas G = 0.731 - 0.7 = 0.031 moles.

Ratio of Rates of diffusion of H2 & Gas G = 0.7 / 0.031

As per Graham's law:   0.7/0.031 = √ [ M / 2]     , M = molar mass of Gas G.
           => M = 1019.77 gms/mole

kvnmurty: :-)
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