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Story problems are often contrived. Puns are often unappreciated. But, if you can't have fun at work, why go to work at all! I like these kind of problems, since they usually make it clear which students are paying attention and which ones are just memorizing the facts. You need to internalize the information to answer these types of questions. Here are some of my faves from our first year course in the equilibrium section. Please post yours, or better yet, submit it as a learning object! You can expect to find these on the site shortly under the problem set question section.
First, an easy one:
Timothy Toxic very carefully weighs out 0.2151 moles of NaCN and gives it to his lab partner, Daphne Dilution. Daphne adds the NaCN to a 1.000 L volumetric flask and dilutes it up to the line. Timothy then asks their instructor, Peter P. Aitchmeter to measure the pH of the solution using a very accurate pH meter.
a) List all dissolved species at equilibrium.
b) give a complete system of equations that could be used to find the pH.
c) Solve the system of equations to find the pH. Clearly state all assumptions (if made).
Now a more difficult one, including some nasty unit conversions:
While working in the laboratory, you spill 1 mL of mercury. While trying to flee, you accidentally lock yourself in, cut off the power to the ventilation system, and disconnect the phone. Your lab is 12 feet by 12 feet by 9 feet. The toxic level of Hg vapor is 29 mg/m3 and the legal limit of exposure to Hg vapor is 0.025 mg/m3. Should you be concerned about this spill? Why or why not?
Useful information: P(Hg,298 K) = 0.0012 mm Hg; density of Hg = 13.534 g/mL; paramedics = 911.
First, an easy one:
Timothy Toxic very carefully weighs out 0.2151 moles of NaCN and gives it to his lab partner, Daphne Dilution. Daphne adds the NaCN to a 1.000 L volumetric flask and dilutes it up to the line. Timothy then asks their instructor, Peter P. Aitchmeter to measure the pH of the solution using a very accurate pH meter.
a) List all dissolved species at equilibrium.
b) give a complete system of equations that could be used to find the pH.
c) Solve the system of equations to find the pH. Clearly state all assumptions (if made).
Now a more difficult one, including some nasty unit conversions:
While working in the laboratory, you spill 1 mL of mercury. While trying to flee, you accidentally lock yourself in, cut off the power to the ventilation system, and disconnect the phone. Your lab is 12 feet by 12 feet by 9 feet. The toxic level of Hg vapor is 29 mg/m3 and the legal limit of exposure to Hg vapor is 0.025 mg/m3. Should you be concerned about this spill? Why or why not?
Useful information: P(Hg,298 K) = 0.0012 mm Hg; density of Hg = 13.534 g/mL; paramedics = 911.