Question

In lab practices, we use average atomic mass for calculations, not the mass of an isotope. Will this give us accurate or inaccurate lab data? Please explain why.

A) Accurate; it accounts for various isotopes' contributions
B) Accurate; average atomic mass is precise
C) Inaccurate; it doesn't consider specific isotope masses
D) Inaccurate; average atomic mass is an estimate

Answer 1

Using average atomic mass in lab calculations is accurate as it represents the weighted average of an element's isotopes, calculated based on their individual masses and relative abundances, as reflected in the periodic table. Thus, the option A is the correct answer.

Step-by-step explanation:

In laboratory practices, using average atomic mass for calculations is considered accurate; it effectively accounts for the various isotopes' contributions to the sample. Since most elements occur as mixtures of isotopes, the average atomic mass represents the weighted average of these isotopes as they are found naturally. This approach considers both the individual isotopes' masses and their relative abundances.

For example, carbon's average atomic mass is a weighted average of its two main isotopes, 12C and 13C, with their respective abundances and masses contributing to the final calculated value. This ensures that the atomic mass reflects the actual proportion of the isotopes present in a typical sample.

The periodic table provides the weighted average atomic mass of each element, which is crucial for accurate calculations in chemical reactions and for determining the formula mass of substances.