Consider the chemical equation. 2nbr3 + 3naoh mc008-1.jpg n2 + 3nabr + 3hobr if there are 40 mol of nbr3 and 48 mol of naoh, what is the excess reactant?

Answer is: NBr₃ is the excess reactant.

Balanced chemical reaction: 2NBr₃ + 3NaOH → N₂ + 3NaBr + 3HBrO.

n(NBr₃) = 40 mol; amount of substance.

n(NaOH) = 48 mol.

From chemical reaction: n(NBr₃) : n(NaOH) = 2 : 3.

40 mol : n(NaOH) = 2 : 3.

n(NaOH) = 60 mol; for 40 moles of NBr₃, 60 moles of NaOH is needed, because there is only 48 moles, not all NBr₃ will react (onl 32 moles, 16 moles are excess).

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.