I don't think so.
%Carbon = (3*atomic mass C/molar mass C3H8)*100 = ?
A. 18.20%
B. 20.0%
C. 81.8%
D. 85.0%
I say A
%Carbon = (3*atomic mass C/molar mass C3H8)*100 = ?
To find the molar mass of carbon (C), we take the atomic mass of carbon from the periodic table, which is approximately 12.01 g/mol.
Next, we calculate the molar mass of the entire compound C3H8.
The molar mass of carbon (C) is 12.01 g/mol, and there are three carbon atoms in C3H8, so the mass of carbon in the compound is 12.01 g/mol x 3 = 36.03 g/mol.
The molar mass of hydrogen (H) is approximately 1.01 g/mol, and there are eight hydrogen atoms in C3H8, so the mass of hydrogen in the compound is 1.01 g/mol x 8 = 8.08 g/mol.
To find the molar mass of C3H8, we add the molar masses of carbon and hydrogen: 36.03 g/mol + 8.08 g/mol = 44.11 g/mol.
Next, we determine the percent by mass of carbon in C3H8 by dividing the mass of carbon by the molar mass of the compound and multiplying by 100%.
(36.03 g/mol / 44.11 g/mol) x 100% = 81.72%
Therefore, the correct answer is C. 81.8%.