Standardized NaOH solutions are typically restandardized if left unused for more than a week or two. The main concern is exposure to the atmosphere (thus it is important to seal the bottle well each time, and not leave it open during a lab period). Why is exposure to the atmosphere a concern (be specific)? 1. If a titration net volume should be 20.00 mL and a student accidentally goes one drop past this endpoint (~0.05 mL), what will the percent error in this titration be?
2. If the incorrect titration net volume described in question 3 is used to standardize an NaOH solution, will the calculated [NaOH] be higher or lower than the true value of that solution’s concentration? Explain briefly.

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.