To determine which of the given formulas is an empirical formula, we must first understand what defines an empirical formula. An empirical formula represents the simplest whole-number ratio of the elements in a compound. Now, let's analyze each given formula to determine if it fits this definition.
1. [tex]\( N_2O_4 \)[/tex]:
- This chemical formula represents dinitrogen tetroxide.
- The ratio of nitrogen to oxygen in [tex]\( N_2O_4 \)[/tex] is [tex]\( 2:4 \)[/tex].
- This ratio can be simplified to [tex]\( 1:2 \)[/tex], so the empirical formula would be [tex]\( NO_2 \)[/tex].
2. [tex]\( C_8H_{18} \)[/tex]:
- This chemical formula represents octane.
- The ratio of carbon to hydrogen in [tex]\( C_8H_{18} \)[/tex] is [tex]\( 8:18 \)[/tex].
- This ratio can be simplified to [tex]\( 4:9 \)[/tex], which means [tex]\( C_8H_{18} \)[/tex] is not in its simplest form.
3. [tex]\( CO_2 \)[/tex]:
- This chemical formula represents carbon dioxide.
- The ratio of carbon to oxygen in [tex]\( CO_2 \)[/tex] is [tex]\( 1:2 \)[/tex].
- This ratio is already in its simplest form and cannot be simplified further, so [tex]\( CO_2 \)[/tex] is an empirical formula.
4. [tex]\( C_2H_2 \)[/tex]:
- This chemical formula represents acetylene.
- The ratio of carbon to hydrogen in [tex]\( C_2H_2 \)[/tex] is [tex]\( 2:2 \)[/tex].
- This ratio can be simplified to [tex]\( 1:1 \)[/tex], so the empirical formula would be [tex]\( CH \)[/tex].
Given these analyses, the correct answer is:
CO_2 [tex]\( \rightarrow \)[/tex] Option 3
