L 10) A pure sample of an element was vaporized and injected into a mass spectrometer
and the data was plotted on the graph below. The mass values for the isotopes
were found to be: A–50 (49.946 amu), A-52 (51.941 amu), A-53 (52.941 amu),
and A-54 (53.939 amu). Find the average atomic mass and identify the element.

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.