Which description BEST describes a particle that contains 18 electrons, 18 neutrons and 16 protons? A) an ion with a charge of negative 2
B) an ion with a charge of positive 2
C) an atom with an atomic number of 18
D) an atom with a mass of 34 amu

Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. in the first step, nitrogen and hydrogen react to form ammonia: (g) (g) (g) in the second step, ammonia and oxygen react to form nitric acid and water: (g) (g) (g) (g) calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions. round your answer to the nearest .