Atoms And Molecules

The molecule CO contains two -bonds from the C–O single bond and two -bonds from the double bond between C and O. Thus, it has 2 -bonds and 2 -bonds.

Methane has the molecular formula: The atomic mass of carbon is: The atomic mass of hydrogen is: Since methane contains four hydrogen atoms, the total mass of hydrogen is: So the molecular mass of methane is: Now the mass of carbon present in one mole of methane is: Therefore, percentage of carbon in methane is:
Hence, the percentage composition of carbon in methane is:

Step 1: Understanding the Concept:
Percentage composition defines the mass percentage of each element present in a compound. It represents what portion of the total mass of the compound is contributed by a specific element.
Step 2: Key Formula or Approach:
The formula to calculate the mass percentage of an element is:

Step 3: Detailed Explanation:
The chemical formula for methane is .
First, we need the standard atomic masses of the constituent elements:
- Atomic mass of Carbon ( )
- Atomic mass of Hydrogen ( )
Next, calculate the total molar mass of methane ( ):



Now, calculate the mass percentage of Carbon:


Simplify the fraction:

Step 4: Final Answer:
The percentage composition of carbon in methane is 75%.