Naturally occurring zirconium exists are five isotopes. axe with a mass of 89.905 u(51.45%); zr with a mass of 90.906 u (11.22%); zr with a mass of 91.905 u (17.15%); zr with a mass of 93.906 u (17.38%) and zr with a mass of 95.908 u (2.80%). calculate the average mass of zirconium.

Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. an industrial chemist studying this reaction fills a 25.0l tank with 4.5 mol of sulfur dioxide gas and 4.5 mol of oxygen gas at 30.°c. he then raises the temperature, and when the mixture has come to equilibrium measures the amount of sulfur trioxide gas to be 1.4 mol. calculate the concentration equilibrium constant for the reaction of sulfur dioxide and oxygen at the final temperature of the mixture. round your answer to 2 significant digits.