Select the best answer for the question.

8. The molecular mass of sodium oxide [tex]\left( \text{Na}_2 \text{O} \right)[/tex] is

A. 45.97954
B. 38.98917
C. 22.98977
D. 61.97894



Answer :

To determine the molecular mass of sodium oxide ([tex]\(\text{Na}_2\text{O}\)[/tex]), we need to calculate the combined mass of all the atoms in one molecule of the compound.

1. Sodium oxide ([tex]\(\text{Na}_2\text{O}\)[/tex]) consists of two sodium (Na) atoms and one oxygen (O) atom.
2. The atomic mass of one sodium atom is 22.98977.
3. The atomic mass of one oxygen atom is 15.999.

To find the molecular mass of sodium oxide, we sum the masses of the constituent atoms:
[tex]\[ \text{Molecular mass of Na}_2\text{O} = 2 \times \text{mass of Na} + \text{mass of O} \][/tex]
[tex]\[ \text{Molecular mass of Na}_2\text{O} = 2 \times 22.98977 + 15.999 \][/tex]

Now we add these values together:
[tex]\[ 2 \times 22.98977 = 45.97954 \][/tex]
[tex]\[ 45.97954 + 15.999 = 61.97854 \][/tex]

Therefore, the molecular mass of sodium oxide ([tex]\(\text{Na}_2\text{O}\)[/tex]) is [tex]\(\boxed{61.97854}\)[/tex].

Among the given options, the best match for this value is:
D. 61.97894