What is the percentage by mass of oxygen in nitroglycerin?

Sure, to find the percentage by mass of oxygen in nitroglycerin, we need to follow these steps:

1. First, we need to know the molecular formula of nitroglycerin, which is C3H5N3O9.

2. Next, we need to calculate the molar mass of nitroglycerin. The molar mass of carbon (C) is approximately 12.01 g/mol, hydrogen (H) is 1.01 g/mol, nitrogen (N) is 14.01 g/mol, and oxygen (O) is 16.00 g/mol.

   So, the molar mass of nitroglycerin = (312.01 g/mol) + (51.01 g/mol) + (314.01 g/mol) + (916.00 g/mol) = 227.09 g/mol.

3. Then, we need to calculate the total mass of oxygen in the formula, which is 9*16.00 g/mol = 144 g/mol.

4. Finally, we find the percentage by mass of oxygen in nitroglycerin by dividing the total mass of oxygen by the molar mass of nitroglycerin and then multiplying by 100.

   So, the percentage by mass of oxygen = (144 g/mol / 227.09 g/mol) * 100 = 63.4%.

Therefore, the percentage by mass of oxygen in nitroglycerin is approximately 63.4%.