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

73.89 g/mol

Explanation:

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

the answer would be c

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.