Can someone help me please

Problem page gaseous ethane reacts with gaseous oxygen gas to produce gaseous carbon dioxide and gaseous water . if of water is produced from the reaction of of ethane and of oxygen gas, calculate the percent yield of water. be sure your answer has the correct number of significant digits in it.

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

If 1.8 l of water is added to 2.5l of a 7.0 m koh solution, what is the molarity of the new solution