Answer: Antoine Lavoisier.
He classified the elements into four groups: elastic fluids, nonmetals, metals and earths. Some of the called elementes were not really elements (light and heat). Others were compounds, e.g. hydrochloric acid.
Answer:
a. -29.8 kJ/mol-rxn
Explanation:
For a chemical reaction system the forward and reverse rate are equal. The standard molar enthalpy formation of NH3 is -45.9 kJ/mol. For the enthalpy of NH3 (8) the molar enthalpy is -29.8kJ/mol. The molar mass of N2 = 28.02g/mol. Molar enthalpy of formation is standard amount of substance produced in the formation of a reaction. The molar enthalpy is the change in enthalpy due to reaction per mole.
I can tell you there certainly is enough information, so we can eliminate the fourth option right away.
Group two elements tend to form 2+ cations, and nitrogen forms 3- anions. To make a stable substance, we need those to cancel out. Calling the group 2 element X:
N2X3 would cause the charge to be 2(-3) + 3(2) = 0
This would mean 3 ions of X and 2 anions of N would be a stable ionic compound.
