Question

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Solve only-38,42,43,45,47,48

Answer 1

38.      P V =   n R T =  (m/M) RT,        d = m/V
            P  =  (d / M) R T
         find   M = d R T / P
                P = 764 mm * 13.6 * g              , g = acceleration due to gravity
        from M,  using formulas   for  NO, N2O, NO2, NO3, N3O, N2O2... check which one matches.

42.     P = 0.61 kPa  =  0.61 * 1000 * N/m^2
         P = density of Hg * acceleration due to gravity g * height of Hg column in barometer
         height in meters Hg  = h = P / [13.6 *1000 kg/m^3   *  g in m/sec^2 ]
                     g = 9.81 m/sec^2  or  10 m/sec^2
          height in mm = h * 1000

43.     d1 = 6.095 gm/ml            1 torr = 1 atm / 760
           P = 740 mm Hg         
            ie., height of mercury column is 740 mm in barometer..
           P = density of liquid * g * height of liquid inside barometer tube
              as pressure is same..    h is inversely proportional to density.
                      h1  d1 = h2 d2       =>  h2 = 13.6 * 740 / 6.095   mm
                convert to cm..

45.        V1, P1 are given..
          P2 at 10 ft =   10 * (12 * 2.54 * 10) mm water + P1
              P1 = 760 mm Hg 
          P2 =   P1 +  10 * (12*25.4) * density of water/density of Hg    mm Hg
                      = 760 + 120*25.4 * 1/13.6   mm Hg
              P1  V1  = P2 V2
                     10 feet of water =  10* 12 * 25.4 /13.6   mm of Hg

47.     m1 / m2  = 2.375/ 1.00 = M2 / 32              32 = molecular mass of O2..
              which gas has molecular weight = M2 ? check..

48.     m = 6.81 gm         V = 1.16  * 10^4 L         T = -23 C     convert to kelvin
           P V = m/M  R T
           P1  = m1 R T / (V1 * M)    
              convert  P1 in dynes/cm^2  or  N/m^2
           m2 = P2 V1    M / (R T)
                  P2 = 4.0 * 10^-3 atm  convert to  N/m^2  or  dynes/cm^2
                So  if V,  T   remain same...    m  is proportional to pressure.
         answer  m2 - m1..