PLZ help me with these crazy ap chem problems

muchograndechica
Thu, 27 Sep 2007 23:51:42 +0000

Can you solve these problems step by step? Thanks a bunch.

1). In 1897 the Swedish explorer Andree tried to reach the North Pole in a balloon. The balloon was filled with hydrogen gas. The hydrogen gas was prepared from iron splints and diluted sulfuric acid. The reaction is given below.
Fe(s) + H2SO4(aq) FeSO4(aq) + H2(g)

The volume of the balloon was 4800 m^3 and the loss of hydrogen gas during filling was estimated at 20.%. What mass of iron splints and 99% (by mass) H2SO4 were needed to ensure the complete filling of the balloon? Assume a temperature of 0°C, a pressure of 1.0 atm during filling, and 100% yield.

2). A 2.45 L sample of O2(g) was collected over a liquid at a total pressure of 785 torr and 25°C. When the O2(g) was dried (vapor of that liquid removed), the gas had a volume of 1.75 L at 25°C and 785 torr. Calculate the vapor pressure of this liquid at 25°C