Sometimes in lab we collect the gas formed by a chemical reaction over water $($see sketch at right$).$ This makes it easy to isolate and measure the amount of gas produced.

Suppose the $O_2$ gas evolved by a certain chemical reaction taking place at $45\mathrm{.}0C$ is collected over water, using an apparatus something like that in the sketch, and the final volume of gas in the collection tube is measured to be $109.mL.$

Calculate the mass of $O_2$ that is in the collection tube. Round your answer to $2$ significant digits. You can make any normal and reasonable assumption about the reaction conditions and the nature of the gases.

${10}^{}$