Mr(HNO3)=

The molar mass (Mr) of nitric acid (HNO₃) can be calculated by adding the atomic masses of its constituent elements:

• Hydrogen (H): approximately 1.01 g/mol
• Nitrogen (N): approximately 14.01 g/mol
• Oxygen (O): approximately 16.00 g/mol (and there are three oxygen atoms in nitric acid)

Now, calculate the molar mass:

\[ \text{Mr(HNO}_3) = \text{Mr(H)} + \text{Mr(N)} + 3 \times \text{Mr(O)} \]

\[ \text{Mr(HNO}_3) = 1.01 \, \text{g/mol} + 14.01 \, \text{g/mol} + 3 \times 16.00 \, \text{g/mol} \]

\[ \text{Mr(HNO}_3) = 1.01 + 14.01 + 48.00 \]

\[ \text{Mr(HNO}_3) = 63.02 \, \text{g/mol} \]

So, the molar mass of nitric acid (HNO₃) is approximately 63.02 g/mol.