Final answer:
The question pertains to the discrepancy between experimental and expected enthalpy values in chemistry, where a lower than expected experimental value suggests a negative deviation possibly due to inherent methodological limitations.
Step-by-step explanation:
The question 'Lower enthalpy than expected experimental error. A) True B) False' relates to the concept of enthalpy in chemistry, particularly the comparison between experimental enthalpy values and expected or theoretical values. When the experimental value of enthalpy is lower than expected, it indicates a negative deviation, which could happen due to various reasons such as experimental error or the application of mean bond enthalpies in calculations. In contrast, a positive deviation occurs when the vapor pressure is greater than predicted.
It is important to note that experimental procedures, including enthalpy determination, are subject to errors. For instance, enthalpies of formation can be used to calculate the experimental value of enthalpy changes; however, any discrepancies observed might be attributed to the use of mean bond enthalpies which are averages and might not account accurately for specific molecular contexts. This does not necessarily imply an experimental error, but rather a limitation of the methods used. Furthermore, in the field of chemical energies, the approximate formula may yield results that are favorably compared to true values, as seen with the fractional mass considerations for different elements.