(c)Dinitrogen tetraoxide in its liquid state was used as one of the fuels on the lunar Lander expeditions for a NASA space vessel. In the gas phase it decomposes to gaseous nitrogen dioxide as shown in the following equation:
N2O4was allowed to reach equilibrium at 4000C where Ksp= 0.133atm. At equilibrium the pressure of N2O4(g) was found to be 2.71atm.
(i)Write the equilibrium expression in terms of the concentration.
(ii)Write the equilibrium expression in terms of the partial pressures. (iii) Calculate the equilibrium pressure of NO2(g)
(c)(i) The melting point of camphor is 176.50C. When0.125g of sulphur is finely ground and mixed with 3.62g of camphor, the resultant mixture melts at 171.40C. What is the molecular weight of sulphur in camphor?
(ii)Water and ethanol form an azeotropic mixture of composition 95.6% ethanol which boils at 78.150C. Sketch a well labelled temperature composition curve for the water-ethanol mixture. Explain whether it is possible to obtain pure ethanol from a water-ethanol mixture.
(c)The atomic radius of sodium is cm and the molar volume of sodium is 23.68cm3. If 68.52% of this volume is the actual volume occupied by sodium atom, calculate the Avogadro's constant. (Volume of one sodium atom =?x3).
(d)One mechanism for the removal of excess heat generated by metabolic processes in the body is evaporation of the water in sweat. In a hot, dry climate as much as 1.5 litres per day may be lost by one person. Calculate the amount of heat required to evaporate this water at T = 460C. (AH vap = 43.02kJmo F1at 460C)