To find the molar mass of sodium phosphate ([tex]\( \text{Na}_3\text{PO}_4 \)[/tex]), we need to determine the molar mass of each element in the compound and then sum these contributions according to the number of each type of atom present in one formula unit.
1. Identify the number of each type of atom in [tex]\( \text{Na}_3\text{PO}_4 \)[/tex]:
- Sodium (Na): 3 atoms
- Phosphorus (P): 1 atom
- Oxygen (O): 4 atoms
2. Determine the molar mass of each element (values in g/mol):
- Sodium ([tex]\( \text{Na} \)[/tex]): 22.989 g/mol
- Phosphorus ([tex]\( \text{P} \)[/tex]): 30.974 g/mol
- Oxygen ([tex]\( \text{O} \)[/tex]): 15.999 g/mol
3. Calculate the contribution of each element to the molar mass of [tex]\( \text{Na}_3\text{PO}_4 \)[/tex]:
- Sodium: [tex]\( 3 \times 22.989 \, \text{g/mol} = 68.967 \, \text{g/mol} \)[/tex]
- Phosphorus: [tex]\( 1 \times 30.974 \, \text{g/mol} = 30.974 \, \text{g/mol} \)[/tex]
- Oxygen: [tex]\( 4 \times 15.999 \, \text{g/mol} = 63.996 \, \text{g/mol} \)[/tex]
4. Sum the contributions to find the total molar mass:
[tex]\[
68.967 \, \text{g/mol} + 30.974 \, \text{g/mol} + 63.996 \, \text{g/mol} = 163.937 \, \text{g/mol}
\][/tex]
Therefore, the molar mass of [tex]\( \text{Na}_3\text{PO}_4 \)[/tex] is [tex]\( \boxed{163.94 \, \text{g/mol}} \)[/tex], rounding to the hundredths place.
The correct answer is:
A. [tex]\( 163.94 \, \text{g/mol} \)[/tex]
