What is the molar mass of lactic acid, #C_3H_6O_3#?
Before we begin here's a tip:
atomic weight of element
First, you want to have your handy dandy periodic table available so you can determine the atomic weight of C, H, O
C has an atomic weight of 12.01 g/mol
H has an atomic weight of 1.008 g/mol
O has an atomic wight of 16.00 g/mol
Based on the chemical formula, we have 3 atoms of carbon so you would multiply the atomic weight of C by 3 to obtain 36.03 g/mol.
You do the same for hydrogen, we have 6 atoms of H so you multiply the atomic weight of H by 6 to get 6.048 g/mol
Lastly, for O you would multiply 16.00g/mol by 3 to obtain 48.00 g/mol
Now you want to add the mass of each atom together to obtain the molecular weight of the entire compound:
48.00 g/mol + 6.048 g/mol + 36.03 g/mol = 90.08 g/mol