Your stomach is a chemical reactor. When you devour a fast food $0.99 hamburger in about a minute, it acts like an instantaneous input of 350 g of food entering the stomach. In response, the stomach starts producing gastric liquids (acids), which are continuously excreted into the stomach at a rate of 12.0 mL/min as the hamburger is digested. The fluid also leaves the stomach to the small intestine at a flow rate of 12.0 mL/min, so the volume of the liquid in the stomach stays constant at 1.15 L. The hamburger digestion rate constant is 1.33 hr-1. A. What kind of ideal reactor would you model your stomach as?
B. What fraction of the hamburger's mass will remain undigested in your stomach one hour after you eat the hamburger?

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?