Answer:
Explanation:
Hey,
so here the student is saying that the given mass is of one atom. But when we usually talk about amu it is the unified atomic mass so mass of all the atoms present.
So that's why he is wrong.
Also the definitions states,
The atomic mass of an element is the average mass of the atoms of an element measured in atomic mass unit (amu, also known as daltons, D). The atomic mass is a weighted average of all of the isotopes of that element, in which the mass of each isotope is multiplied by the abundance of that particular isotope.
The molecular formula would be Li2CO3
The answer is the percent composition which is number 4. This is the percent by mass of each element existing in a compound. To compute for this, you need to find two things: the mass of just the element, and the molar mass of the entire compound. Afterwards, you take the molar mass of only the element and divide it by the molar mass of the entire compound, and multiply by 100%.