What is the percentage by mass of hydrogen in ethanoic acid?
Show workings bit by bit
Ethanoic acid has the molecular formula CH3COOH.
Let's find the molar mass of the component atoms:
- Carbon (C) has a molar mass of 12 g/mol.
- Hydrogen (H) has a molar mass of 1 g/mol.
- Oxygen (O) has a molar mass of 16 g/mol.
Now, let's find the molar mass of ethanoic acid:
- It contains 2 carbon atoms, 4 hydrogen atoms, and 2 oxygen atoms.
- Molar mass of ethanoic acid = (2 × 12) + (4 × 1) + (2 × 16) = 24 + 4 + 32 = 60 g/mol.
Next, let's calculate the mass of hydrogen in ethanoic acid:
- The mass of hydrogen = (Number of hydrogen atoms) x (Molar mass of hydrogen)
- The mass of hydrogen = 4 x 1 = 4 g.
Finally, let's find the percentage by mass of hydrogen in ethanoic acid:
- Percentage = (Mass of hydrogen / Molar mass of ethanoic acid) x 100
- Percentage = (4 / 60) x 100 = 0.0667 x 100 = 6.67%.
So, the percentage by mass of hydrogen in ethanoic acid is approximately 6.67%.