3. (15 points) Liquid butane is to be burned with excess air. The engineer designing the fumace must calculate the highest temperature that the furnace walls will have to withstand so that an appropriate material of construction can be chosen. Assuming that the butane is fed at 25C and the air enters at 100C, the engineer calculates the maximum temperature to be 1700C. Calculate the percentage excess air fed to the reactor. You may assume that air only consists of oxygen and nitrogen