How many molecules are in 92 liters of butane at stp show work

The ammonia molecule in the diagram has the observed bond orientation because

How many lone pairs of electrons are on the central atom of no3- and what is the molecular shape? one, trigonal planar zero, trigonal pyramidal zero, trigonal planar one, tetrahedral one, trigonal pyramidal

20 grams of water. she poured out 15 grams. which of the following physical properties of the water changes? a .boiling point b. density c .electrical conductivity d .volume