1.A surveyor is going to take a 5.5 mile sight across a lake from the top of one tower to a target on the top of another tower. It is desired to keep the line of sight 6 ft above the lake surface. At what equal heights above the shorline should the instrument and the target be located?
2.What will be the pH of a solution prepared by adding 10^-2 moles of hydrofluoric acid (HF) to 1 L of pure water? The pKa of HF is 3.2.
a) that for conservation of mass equilibrium 10^-2 moles = [HF] + [F-]
b) to maintain electroneutralty [H+] = [OH-] + [F-]
c) assume [HF] > [F-]
d) assume [F-] > [OH-]