To find the molecular mass of sodium oxide (Na₂O), we need to consider the atomic masses of sodium (Na) and oxygen (O), as well as the molecular structure of sodium oxide. Let's break it down step by step:
1. Find the atomic masses from the periodic table:
- The atomic mass of sodium (Na) is approximately 22.98977.
- The atomic mass of oxygen (O) is approximately 15.999.
2. Understand the composition of sodium oxide (Na₂O):
- Sodium oxide consists of two sodium (Na) atoms and one oxygen (O) atom.
3. Calculate the total molecular mass of sodium oxide:
- Since there are two sodium atoms in the compound, we multiply the atomic mass of sodium by 2:
[tex]\[
2 \times 22.98977
\][/tex]
- Next, we add the atomic mass of one oxygen atom:
[tex]\[
2 \times 22.98977 + 15.999 = 45.97954 + 15.999
\][/tex]
- This gives the total molecular mass:
[tex]\[
61.97854
\][/tex]
Therefore, the molecular mass of sodium oxide (Na₂O) is 61.97854.
So, the correct answer is:
A. 61.97854
