a) A 1.500 L flask is filled with a mixture of 1.20 g H2 and 8.40 g O2, at 25°C. The mixture is ignited, and hydrogen and oxygen combine to form water.
What is the total pressure inside the flask before the reaction? (Report your answer in units of atmospheres.)
What is the total pressure after the reaction, once the flask is returned to 25°C? (Vapour pressure of water at 25°C is 23.8 mm Hg.)
b) In the photoelectric effect, the work function is the energy that must be supplied to overcome the attractive forces that hold an electron in the metal. For mercury, the work function is equal to 435 kJ mol-1 of photons. What is the kinetic energy, in joules, of the ejected electrons when light with a wavelength of 220 nm strikes the surface of mercury?