1) Bromine gas reacts with flourinne gas to give a low boiling liquid. A sample of this liquid is vaporized at 42.0 degrees C into a flask with a volume of 252.2mL. The atmospheric pressure is 726.3 torr. The flask is found to contain 1.632 g of the compound.
a) Calculate the formula weight of the compound.
b) Is the compound bromine triflouride, bromine pentaflouride or dibromine hexaflouride?
2) Calculate the volume of H2 gas collected over water at 70.0 degreesC and a barometric pressure of 748.3 torr from the reaction of 1.588g of magnesium with excess hydrochloric acis.
n = PV/RT
P = 726.3torr (1 atm/760 torr) = 0.9557 atm
V = 0.2522 L
T = 42.0 + 273.15 K = 315.2 K
R = 0.08205 L*atm/mol*K
plug these things in for n gives...
n = 0.009320 mol
molecular weight = mass / moles = ...
The solution is found using the ideal gas law N = PV/RT. The formula weight of a compound is discussed.