Someone please help me with this again lol pls

Ibeg you to me 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?

Me with this assignment ! i only partially understand, so explain. also it's a work sample. at the championship bike race, steve and paula were fighting for first place. steve was 175 feet ahead of paula and had only 300 feet left to go. he was very tired and was going only 9 feet per second. paula was desperate to catch up and was going 15 feet per second. who won the bike race and by how far did she/he win?

22 points algebra 1//sum and product of rational and irrational numbers. dont have to do all 4 if could much : )) write an example: 1) how the product of two identical irrational numbers can be a rational number. 2) how the product of two different irrational numbers can be a rational number. 3) write a quotient of intergers that is not a real number. 4) is the set of positive irrational numbers closed for the operation of division? if not give a counter example.