What is the molar mass of NaNO3? A. 34.0 g B. 37.0 g C. 53.0 g D. 75.0 g E. 85.0 g
The Correct Answer and Explanation is:
The correct answer is:
E. 85.0 g
Explanation:
To find the molar mass of a compound like sodium nitrate (NaNO₃), you must add up the atomic masses of each element present in one mole of the compound. Use the periodic table values for each atom:
- Sodium (Na): 22.99 g/mol
- Nitrogen (N): 14.01 g/mol
- Oxygen (O): 16.00 g/mol, and there are three oxygen atoms
Now calculate the total molar mass:Molar mass of NaNO3=(1×22.99)+(1×14.01)+(3×16.00)\text{Molar mass of NaNO}_3 = (1 \times 22.99) + (1 \times 14.01) + (3 \times 16.00)Molar mass of NaNO3=(1×22.99)+(1×14.01)+(3×16.00)=22.99+14.01+48.00=85.00 g/mol= 22.99 + 14.01 + 48.00 = 85.00 \text{ g/mol}=22.99+14.01+48.00=85.00 g/mol
Thus, the molar mass of sodium nitrate is 85.0 grams per mole.
Why It Matters:
Understanding molar mass is critical in chemistry because it allows us to convert between the mass of a substance and the number of moles. Moles are a standard unit in chemistry for counting particles like atoms or molecules.
For example, if you are asked to prepare a solution with one mole of NaNO₃, you would weigh out exactly 85.0 grams. This ensures proper stoichiometry in reactions, meaning the chemical quantities react in correct proportions.
This calculation is also essential in fields like environmental science, where sodium nitrate may be a component in fertilizers, and in medical laboratories where precise chemical measurements are required for accurate testing and analysis.
