A 1.509 g sample of asmium oxide which melts at 40 C and boils at 130 C degrees is placed inot a cylinder with a movable piston that can expand against the atomospheric pressure of 745 torr. Whe the sample is heated to 200 degrees c, it is completely vaporized and the volume of the cylinder expandes by 235 mL. What is the molar mass of the oxide? Asuming that the oxide is OsOx, find X?
So what do I do? Pl. tell me how to do it. I have to study for the test tomorrow and I need help quickkkkkkkk.
~~thax~~*_*~~~
2007-10-22 11:24:24 · 1 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
Use ideal gas law!
Unfortunately, the initial volume is not given. ---Assume it is zero.
n = PV/RT = (745/760)*0.235/(0.08206*473) = 0.00593
Hence the molar mass of OsOx is: 1.509/0.00593 = 254
The molar mass of Os is: 190. So X = 4 and the oxide is OsO4.
2007-10-23 12:02:57 · answer #1 · answered by Hahaha 7 · 0⤊ 0⤋