(3) The rate constant for an elementary, gas-phase reaction: 2A+B2C is k. The reaction is taking place in a continuous stirred tank reactor (CSTR). The concentrations entering the reactor are CA0=CB0=2moldm3,CC0=0moldm3. Which of the following statements is correct (choose all correct answers) ? Answer: (A) rA=kCA2CB (B) yA0=0.5 (C) =0.5 (D) =0.25 (E) rC=2(rB) (4) In the exponential growth phase, the cell growth rate dtdCc=maxCc, and the cell concentration (Cc) doubles every 2.5 hours. Please determine max ? Answer: (A) max=0.28h1 (B) max=0.40h1 (C) max=0.80h1 (D) max=1.73h1 (E) max=2.50h1 (F) None of the above. (5) Which of the following statements about the cell growth in a bioreactor is/are true? Choose all correct answers unless all of A to D are true (in which case you should choose E ). Answer: (A) In a batch bioreactor, cell growth period consists of four typical phases: lag phase, exponential phase, stationary phase, and cell death phase (B) In a batch bioreactor with cell growth in exponential phase, it requires at least 7 generations (doublings) to increase the cell density by more than 100 fold. (C) Feb-batch bioreactor is also called semicontinuous bioreactor, where nutrient solution for cell growth is continuously fed into the bioreactor but no reaction mixture is withdrawn from the bioreactor during the entire fed-batch process. (D) In a steady-state continuous bioreactor, the concentrations of cells, substrate, and product remain unchanged. (E) All of the above