Description
PLEASE SEE INSTRUCTIONS BELOW Notes for Unit VIII Problem Solving
The following are examples of problems where a student is requiredto show work. When working such problems, show as many steps in theprocess as possible. It may be helpful to use the examples from thetextbook or the study guide to model your steps. Showing all steps canhelp your instructor award partial credit in the event that the overallanswer is incorrect but the work is partially correct. A correct answerwithout the demonstration of steps for solving the problem will notreceive full credit.
Example: Place the following two gases inorder of increasing average molecular speed at 300K: H2S and HBr.Explain your answer.
Correct Way to Solve the Problem:
Since there is a small difference between the average molecular speedµavg and the root mean squared (rms) speed µrms we can assume that thefollowing equation is a good reference for determining differences inµavg
µrms = ?(3RT/M)
You will notice that since thetemperature is constant amongst all molecules in the gas phase and thegas phase constant is, indeed, always constant. Therefore, the onlydifference between molecules is their molar mass M. M is in thedenominator so molecules with smaller molar mass (M) will have a highermolecular speed.
MH2S = 34.08 g/mol
MHBr = 80.91 g/mol
So the series for this answers is:
(slowest) HBr < H2S (fastest)
