What volume does 0.25 moles of oxygen gas occupy at stp? 22.4 l2.24 l10.0 l5.60 l

Can someone me with questions 15 to 17 plz.

Cucl2 + 2nano3 cu(no3)2 + 2nacl what is the percent yield of nacl if 31.0 g of cucl2 reacts with excess nano3 to produce 21.2 g of nacl? 49.7% 58.4% 63.6% 78.7%

All of the following are part of the biosphere except