Final answer:
Both a 12.01 g sample of carbon and a 24.3 g sample of magnesium represent one mole of atoms, as their masses are equal to the respective relative atomic masses of carbon and magnesium.
Step-by-step explanation:
A 12.01 g sample of carbon and a 24.3 g sample of magnesium have one thing in common: both samples contain exactly one mole of atoms. This is determined by comparing the sample mass to the relative atomic mass of each element. The relative atomic mass of carbon is approximately 12.01 u, and one mole of carbon weighs 12.01 g. Similarly, the relative atomic mass of magnesium is approximately 24.3 u, and one mole of magnesium weighs 24.3 g. Therefore, both samples described in the question represent one mole of their respective elements.
In chemistry, the mole is a fundamental unit in the International System of Units (SI) for measuring the amount of substance. By definition, one mole contains exactly 6.022 × 10²³ entities (atoms, molecules, ions, or other particles) and is equivalent to the relative atomic mass of a substance expressed in grams.