Question

2.In a mixture of helium, He, oxygen, 02, and methane, CH4, the partial pressures of helium and oxygen are 13.6 kPa and 29.2 kPa, respectively, and the total pressure if 95.4 kPa. The temperature of this mixture is 30°C.
a)What is the partial pressure of methane?

b)Methane undergoes a combustion reaction with oxygen to produce carbon dioxide and water. The UNBALANCED reaction is:

c)If mixture described above is ignited and then cooled back to the original temperature of 30°C, what would be the final pressure inside the container. Assume the volume of the container does not change.

Answer 1

2.

a) What is the partial pressure of methane?

     pCH4 = 95.4 - (13.6+29.2) = 52.6 kpa

b) CH4(g) + O2 (g) ----> CO2(g) + H2O(l)

c)   CH4(g) + 2O2 (g) ----> CO2(g) + 2H2O(l)

        Dn = 1-3 = -2

so that , no of mole of initial gas = 3

             
             no of mole of final gas = 1

   from ideal gas equation

   p1/n1 = P2/n2

   81.8/3 = x/1

x = partial pressure of resulting gas in the reaction = 27.27 kpa

   total pressure = 27.27+13.6 = 40.87 kpa