To determine the molecular weight or molar mass of one mole of H2CO3, we need to consider the atomic masses of the elements that make up this compound.

In H2CO3, we have:

- 2 atoms of Hydrogen (H)

- 1 atom of Carbon (C)

- 3 atoms of Oxygen (O)

The atomic mass of Hydrogen (H) is approximately 1 atomic mass unit (amu).

The atomic mass of Carbon (C) is approximately 12 amu.

The atomic mass of Oxygen (O) is approximately 16 amu.

Considering this information, we can calculate the molecular weight of H2CO3:

Molecular weight (H2CO3) = (2 x atomic mass of H) + (atomic mass of C) + (3 x atomic mass of O)

Molecular weight (H2CO3) = (2 x 1 amu) + (12 amu) + (3 x 16 amu)

Molecular weight (H2CO3) = 2 amu + 12 amu + 48 amu

Molecular weight (H2CO3) = 62 amu

Therefore, the molecular weight of one mole of H2CO3 is approximately 62 grams per mole (g/mol).