1 mole is the number of atoms in exactly
- 1 g of 12C
- 12 g of 12C
- 1/12 g of 12C
- none of these
12 g of 12C
1 mole is the number of atoms in exactly 12 g of 12C.
This is because a mole is defined as the amount of substance that contains the same number of entities (such as atoms or molecules) as there are atoms in 12 grams of the isotope carbon-12 (12C). Since the atomic mass of carbon-12 is 12, one mole of carbon-12 contains 6.022 × 1023 atoms, which is known as Avogadro’s number.