Answer:
The mass percent of carbon in C₁₄H₁₉NO₂ is 72.1%.
Explanation:
To calculate the mass percent of carbon in C₁₄H₁₉NO₂ we have to follow two simple steps:
1st) Look for the <u>atomic weight of each element</u> in the Periodic Table and then <u>multiply each one by its subscript</u> in the molecule and finally <u>sum all</u> of them to find the molar weight of the molecule:
- Carbon atomic weight . Carbon subscript = 12 . 14 = 168g
- Hydrogen atomic weight . Hydrogen subscript = 1 . 19 = 19g
- Nitrogen atomic weight . Nitrogen subscript = 14 . 1 = 14g
- Oxygen atomic weight . Oxygen subscript = 16 . 2 = 32g
The molar weight of C₁₄H₁₉NO₂ is: 168g + 19g + 14g +32g = 233g.
2nd) Find the mass percent of carbon with a <u>Rule of three</u>:
If 233g represents the 100% of mass, the 168g of carbon in the molecule will represents the 72.1% of mass.
The Rule of three is:
233g ------------- 100%
168g ------------- = (168 . 100)/233 = 72.1% mass of carbon.