11. The correct name for P2O5 is (A) phosphorus(II) oxide (B) phosphorus(V) oxide (C) diphosphorus oxide (D) diphosphorus pentoxide (E) phosphorus pentoxide

20. Refer to the following equation: \[ 4\text{NH}_3(g) + 7\text{O}_2(g) \rightarrow 4\text{NO}_2(g) + 6\text{H}_2\text{O}(g) \] How many molecules of NO2 are produced when 5.38 mol of ammonia is completely reacted? (A) 21.52 (B) 6.48 × 1024 (C) 3.24 × 1024 (D) 247 (E) none of these