Carbon tetrachloride is a human carcinogen. Its boiling point is 76.65 degree C.
ID: 475080 • Letter: C
Question
Carbon tetrachloride is a human carcinogen. Its boiling point is 76.65 degree C. (Reference: NST Webbook carbon tetrachloride. Accessed Jan 13, 2017) Research online to find the short term exposure limit (STEL) for carbon tetrachloride. What does the STEL mean? A friend is planning to do an experiment with liquid carbon tetrachloride at 24 degree C on the open bench top in a small (19 m) poorly ventilated room (i.e. consider the room to be a closed system for this question). Convert the STEL to vapour pressure for this room. Disclaimer: You should never work with a human carcinogen outside a fumehood under any circumstances! Using formulas used in this course, calculate the theoretical vapour pressure of carbon tetrachloride inside the room at 24 degree C. Use your data to explain to your friend why she can or cannot do the experiment.Explanation / Answer
a) Acceptable amount of exposure over certain short period of time usually 15 minutes is called as Short Term Exposure Limit.
According to American Conference of Governmental Industrial Hygienists (ACGIH), the STEL value
for CCl4 is 63mg/m3 or 10 ppm
b) 10 ppm = VPccl4 / VProom * 106
c) Using Antoine equation you can find out theoretical vapor pressures
log P = A - B/(C+T)
just plug in all values of A,B,C of CCl4 & T=24oC to get the answer