The diagram shows the molecular structure of propane
The Correct Answer and Explanation is:
B. C₃H₈
To determine the correct chemical formula for propane from its molecular structure, we need to count the number of atoms for each element present in the diagram. A chemical formula is a concise way to express the types of atoms and the number of each type in one molecule of a compound.
First, let’s identify the elements in the structure. The symbols used are ‘C’ for Carbon and ‘H’ for Hydrogen.
Next, we count the number of Carbon (C) atoms. By looking at the central chain of the molecule, we can see there are three ‘C’ symbols linked together: H-(C)-(C)-(C)-H. Therefore, there are 3 carbon atoms in one molecule of propane.
Then, we count the number of Hydrogen (H) atoms. It’s helpful to count the hydrogens attached to each carbon atom systematically:
- The first carbon atom on the left is bonded to 3 hydrogen atoms.
- The second (middle) carbon atom is bonded to 2 hydrogen atoms.
- The third carbon atom on the right is also bonded to 3 hydrogen atoms.
Adding these up gives us the total number of hydrogen atoms: 3 + 2 + 3 = 8 hydrogen atoms.
Finally, we write the chemical formula by combining the element symbols with their respective atom counts as subscripts. For hydrocarbons like propane, the convention is to write the carbon atom first, followed by the hydrogen atom. With 3 carbon atoms and 8 hydrogen atoms, the chemical formula is C₃H₈.
Comparing this result with the given options:
- A. 3CH₈ is incorrect notation.
- B. C₃H₈ matches our derived formula.
- C. C₃H₂ incorrectly states there are only 2 hydrogen atoms.
- D. 3H₂C₃H₃ is an incorrectly formatted and nonsensical formula.
Thus, the correct chemical formula for propane is C₃H₈.
