Question

Up late, a tired engineer calculated the molar mass of nitroglycerin (C3H5N3O9) to be 193.7 g/mol, but this incorrect. What is the percent error of this incorrect molar mass

Answer 1

• The atomic mass of carbon is 12.011 g/mol.
• The atomic mass of hydrogen is 1.00794 g/mol.
• The atomic mass of nitrogen is 14.0007 g/mol.
• The atomic mass of oxygen is
• g/mol.

So, the formula mass of nitroglycerin is$3(12.011)+5(1.00794)+3(14.0007)+9(15.9994)=227.0694 \text{ g/mol}}$

Therefore, the percent error is

$\frac{193.7-227.0694}{227.0694} \times 100=\boxed{-14.70 \% \text{ (to 4 sf)}}$