To find the molar mass of C4H8O4, we need to add up the atomic masses of each element present in the compound.

Molar mass of C4H8O4 = (4 x Molar mass of Carbon) + (8 x Molar mass of Hydrogen) + (4 x Molar mass of Oxygen)

Molar mass of Carbon (C) = 12.01 g/mol

Molar mass of Hydrogen (H) = 1.008 g/mol

Molar mass of Oxygen (O) = 16.00 g/mol

So, the molar mass of C4H8O4 is:

= (4 x 12.01 g/mol) + (8 x 1.008 g/mol) + (4 x 16.00 g/mol)

= 48.04 g/mol + 8.064 g/mol + 64.00 g/mol

= 120.104 g/mol

Therefore, the molar mass of C4H8O4 is 120.104 g/mol.