The molecular weight of ethylene glycol is 62.0689 when calculated using the atomic weights found in a standard periodic table, yet the molecular weight determined experimentally by high-resolution mass spectrometry is 62.0368. Explain the discrepancy.

Molecular weight is calculated by summing the atomic weights of all atoms in a molecule based on the periodic table. Ethylene glycol (C2H6O2) consists of 2 carbon, 6 hydrogen, and 2 oxygen atoms, leading to a theoretical molecular weight of 62.0689 g/mol. This calculation assumes standard atomic weights, which can vary slightly due to isotopic abundance.

Isotopic abundance refers to the relative amounts of different isotopes of an element in nature. The atomic weights listed in the periodic table are weighted averages based on these abundances. Experimental measurements, such as those from mass spectrometry, can yield different molecular weights if the sample contains isotopes in different proportions than those assumed in standard calculations.

Mass spectrometry is an analytical technique used to measure the mass-to-charge ratio of ions. It provides precise molecular weight measurements by detecting the actual mass of molecules in a sample. The discrepancy between the calculated and experimental molecular weights of ethylene glycol may arise from the presence of isotopes or variations in the sample's composition during analysis.