What could cause a less than 100% yield? a. not letting the reaction run long enough and heating the flask b. letting the reaction run too long and cooling the flask c. chemical contaminants and too much reaction time d. chemical contaminants and too little reaction time submit for grading save and finish later?

while cooking a piece of 1/2 pound beef steak, a cast iron pan (2.4kg in weight) was heated 260 celsius.

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.