What is the molar mass of each compound?
a. li2co3 (lithium carbonate)

73.89 g/mol

Explanation:

Molar mass is the mass contained by one mole of an element or a compound.The molar mass of an element is equivalent to its atomic mass, while the molar mass of a compound is equivalent to the relative formula mass of the compound.Relative formula mass of a compound is calculated by getting the sum of the relative atomic masses of all the elements making the compound.

In this case,

Our compound is LI₂CO₃, it is made of 2 Lithium atoms, 1 carbon atom and 3 oxygen atoms.

Atomic mass of O = 16.0

Atomic mass of Li = 6.94

Atomic mass of C = 12.01

Thus, RFM of  LI₂CO₃ = (2  × 6.94 ) + 12.01  + (3 × 16.0)

                                  = 73.89 g/mol

Thus, the molar mass of  LI₂CO₃ is 73.89 g/mol

1. and 2. question: in which equation? or i don't understand you, 3. a), 4. c), 5. c), 6. b), 7. d), 8. d) if small number is underlined(behind symbol) , b) if big number is underlined(in front of symbol)9. what is underlined there? 10. c)

The answer to this is the 3rd choice!