Solid calcium (CaF2) reacts with sulfuric acid to form solid calcium sulfate and gaseous hydrogen fluoride. The HF is then dissolved in water to form hydrofluoric acid. A source of calcium fluoride is fluorite ore containing 96 wt% CaF2 and 4% SiO2. In a typical hydrofluoric acid manufacturing process, fluorite ore is reacted with 93 wt% aqueous sulfuric acid, supplied 15% in excess of the stoichiometric amount. Ninety-five percent of the ore dissolves in the acid. Some of the HF formed reacts with the dissolved silica in the reaction 6 HF + SIO2 (aq) – H2SİF6 (9) + 2 H2O () The hydrogen fluoride exiting from the reactor is subsequently dissolved in enough water to produce 60 wt% hydrofluoric acid. Calculate the quantity of fluorite ore needed to produce a metric ton of acid. Express your answer into three significant figures.

2. 100 mol/h of gaseous ethane is burned with excess air. The fuel is mixed with air before entering the furnace; fuel-air mixture is fed to the furnace at 25oC and 1 atm. All the ethane is consumed in the combustion reaction that occurs in the furnace. A cooling water jacket surrounding the furnace removes all of the heat generated by the combustion reaction. The stack gas leaves the furnace at 25oC and 1 atm and contains 5.32 mole% CO2, 1.60% CO, 7.32% O2 and the balance H2O and N2.a. Use Hess’s Law and the Heat of Combustion to calculate ∆??o (kJ/mol) for complete and incomplete combustion of ethane. b. Calculate the molar percentage of ethane in the fuel gas and the percentage excess air fed to the reactor.c. Calculate rate of heat transferred to the cooling water jacket in kW.

8.39. In the manufacture of nitric acid, ammonia and preheated air are mixed to form a gas containing 10.0 mole% NH3 at 600°C. The ammonia is then catalytically oxidized to form NO2, which is absorbed in water to form HNO3. If ammonia enters the gas blending unit at 25°C at a rate of 520 kg/h and heat is lost from the mixer to its surroundings at a rate of 7.00 kW, determine the temperature to which the air must be preheated. (See Example 8.3-6.)

The pressure of methane (CH4) and acetylene (C2H2) gas mixture in a container is 70.5 torr. This gas mixture is burned with sufficient O2 and converted to CO2 and H2O. The H2O and excess O2 in the environment are removed and only CO2 is left in the container. Since the pressure of CO2 is 96.4 torr at the same temperature, what is the mole fraction of acetylene in the starting gas mixture?