When the following equation is balanced, the coefficients are
NH, (g) +0, (g) → NO, (g) +H,0 (g)

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.