Empirical formula of octane C8H18
The Correct Answer and Explanation is:
The empirical formula of a compound represents the simplest whole-number ratio of the elements in the compound. For octane, the molecular formula is C8H18.
Steps to determine the empirical formula:
- Write the molecular formula:
The molecular formula for octane is C8H18, meaning it contains 8 carbon (C) atoms and 18 hydrogen (H) atoms. - Find the greatest common divisor (GCD):
The ratio of carbon to hydrogen in the molecular formula is 8:18. To simplify this ratio, we need to find the greatest common divisor (GCD) of 8 and 18.
The GCD of 8 and 18 is 2. - Divide both the number of carbon and hydrogen atoms by the GCD:
Divide 8 by 2 to get 4.
Divide 18 by 2 to get 9. - Write the empirical formula:
The ratio of carbon to hydrogen atoms is now 4:9. So, the empirical formula for octane is C4H9.
Explanation:
- The molecular formula represents the actual number of atoms of each element in one molecule of a compound. For octane (C8H18), the number of carbon and hydrogen atoms is given directly.
- The empirical formula represents the simplest integer ratio of the elements. By dividing both the number of carbon atoms (8) and hydrogen atoms (18) by their GCD (2), we obtain the empirical formula C4H9.
- The molecular formula is a multiple of the empirical formula. In this case, C8H18 is exactly twice the empirical formula C4H9, meaning the molecular formula is a dimer (a multiple of the empirical formula).
So, while C8H18 is the molecular formula of octane, the empirical formula is C4H9.
