What is the molar mass of strontium nitrate Sr(NO3)2?
The Correct Answer and Explanation is:
Correct Answer:
The molar mass of strontium nitrate, Sr(NO₃)₂, is 211.63 g/mol.
Detailed Explanation (300 words):
To calculate the molar mass of a compound like strontium nitrate, you must add up the atomic masses of all the atoms in the formula. The atomic mass of each element is found on the periodic table and is expressed in atomic mass units (amu), which correspond directly to grams per mole (g/mol) when calculating molar mass.
The chemical formula for strontium nitrate is Sr(NO₃)₂. This indicates that the compound consists of:
- 1 atom of strontium (Sr)
- 2 nitrate groups (NO₃), which means:
- 2 nitrogen atoms (N)
- 6 oxygen atoms (O)
Now we find the atomic masses for each element:
- Strontium (Sr): 87.62 g/mol
- Nitrogen (N): 14.01 g/mol
- Oxygen (O): 16.00 g/mol
Next, we multiply the atomic masses by the number of atoms in the formula:
- 1 Sr × 87.62 g/mol = 87.62 g/mol
- 2 N × 14.01 g/mol = 28.02 g/mol
- 6 O × 16.00 g/mol = 96.00 g/mol
Now, add all these contributions together:
Molar mass = 87.62 + 28.02 + 96.00 = 211.64 g/mol
Due to rounding conventions or small differences in atomic weights from source to source, some tables might show 211.63 g/mol instead of 211.64. Both values are acceptable within rounding limits.
Understanding molar mass is essential in chemistry because it allows scientists to convert between grams and moles, which is critical in chemical equations, stoichiometry, and laboratory calculations. For example, knowing the molar mass of Sr(NO₃)₂ helps determine how much of the compound is needed to provide a certain amount of strontium ions in a reaction.
