Tips on Questions 29 and 31 on the morning of the first day of the professional exam in 2011

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29. For a certain distillation column, it is known that the feed flow rate F is 1000 kg/h, and the average specific heat capacity is 4.0 kJ/(kg·K)； The heat in the vapor phase at the top of the tower is Hv=786500 kJ/h, the liquid flow leaving the reboiler at the bottom of the tower is W=900 kg/h, and the average specific heat capacity is 4.2 kJ/(kg·K). What is the heat load required for the reboiler (kJ/h), and which of the following values represents it? The feed temperature is known to be 35°C, the temperature of the product at the top of the tower is 25°C, and the temperature of the liquid leaving the reboiler at the bottom of the tower is 100°C. file:///C:/Users/ADMINI~1/AppData/Local/Temp/msohtmlclip1/01/clip_image002.gif A、9.3×105 B、1.12×106 C、2.4×106 D、1.03×106 31. The heat released (in kJ/h) when 10,000 kg/h of H2SO4 with a concentration of 78 wt% is diluted to 25 wt% is which of the following values? Given: The integrated heat of solution for H2SO4 at 78% is: △H1 = -37620 kg/kmol of H2SO4. The integrated heat of solution for H2SO4 at 25% is: △H2 = -69390 kg/kmol of H2SO4. A. -6.0×105 B. -2.5×106 C. -2.5×108 D. -8.5×106