Benzene is classified by the U.S. Department of Health and Human Services (DHHS) as a carcinogen. Exposure to benzene increases the risk of cancer and other illnesses in humans. The Occupational Safety and Health Administration (OSHA) have established that action should be taken when benzene level in air reaches 0.5 ppm. A lab technician has poured liquid benzene (M 5 78.11 kg/kmol) into 10 test tubes with inner diameter of 25 mm. Each test tube holds equal amount of liquid benzene at a level of 1 cm from the top. The benzene vapor pressure is 10 kPa, and evaporation of benzene to the surrounding air is occurring at 25°C and 1 atm. The HVAC system for the laboratory is capable of keeping the air fresh, provided that the rate of benzene vapor being evaporated is below 3 g/h. Determine whether or not the benzene evaporation rate from all ten test tubes would present
health risks to the people in the laboratory.