What is the molar mass of potassium nitrate, KNO3
The Correct Answer and Explanation is:
The molar mass of potassium nitrate (KNO₃) is 101.10 g/mol.
Detailed Explanation
Potassium nitrate, with the chemical formula KNO₃, is a common inorganic compound used in fertilizers, food preservation, and fireworks. To determine its molar mass, we need to sum the atomic masses of each element in the compound, based on their proportions.
Step-by-Step Calculation:
KNO₃ is composed of:
- 1 potassium atom (K)
- 1 nitrogen atom (N)
- 3 oxygen atoms (O)
From the periodic table, the atomic masses of the elements are approximately:
- Potassium (K): 39.10 g/mol
- Nitrogen (N): 14.01 g/mol
- Oxygen (O): 16.00 g/mol
Now calculate the molar mass:Molar mass of KNO₃=(1×39.10)+(1×14.01)+(3×16.00)\text{Molar mass of KNO₃} = (1 \times 39.10) + (1 \times 14.01) + (3 \times 16.00)Molar mass of KNO₃=(1×39.10)+(1×14.01)+(3×16.00)=39.10+14.01+48.00= 39.10 + 14.01 + 48.00=39.10+14.01+48.00=101.11 g/mol= \boxed{101.11\ \text{g/mol}}=101.11 g/mol
(Rounded to 101.10 g/mol for standard usage.)
Why Molar Mass Matters:
Molar mass is a critical concept in chemistry because it serves as the bridge between the microscopic world of atoms and the macroscopic world we can measure. By knowing the molar mass of a compound like KNO₃, chemists can:
- Convert between grams and moles of the substance.
- Calculate the amount of reactants and products in chemical reactions.
- Analyze concentrations in solutions.
For example, if you have 202.2 grams of KNO₃, dividing by the molar mass gives:202.2 g101.10 g/mol=2.00 mol\frac{202.2\ \text{g}}{101.10\ \text{g/mol}} = 2.00\ \text{mol}101.10 g/mol202.2 g=2.00 mol
This kind of conversion is essential for accurate experimental and industrial chemical processes.
In summary, the molar mass of potassium nitrate is 101.10 g/mol, calculated by summing the atomic masses of potassium, nitrogen, and oxygen in the formula KNO₃.
