Question

Calculate the mass of 2.45 x 1024 molecules of Lithium oxide (Li2O)
(Atomic mass of Lithium is 6.9)

Answer 1

Answer:

Let's use this equation to answer the question:

atomic weight of element × number of atoms given by subscript = molar mass

First, you want to have a periodic table available so you can determine the atomic weight of Li and O:

Li has an atomic weight of 6.94 g/mol

O has an atomic weight of 16.00 g/mol

Based on the chemical formula, we have 2 atom of Li, so the atomic weight of Li has to be multiplied by 2 to obtain 13.88 g/mol.

You have 41 atom of O, so the atomic mass would just be 16.00 g/mol

Now you want to add the mass of each atom together to obtain the molar mass of the entire compound: