25.0 g of a hydrocarbon undergoes complete combustion leading to the formation of 77.0  g of CO2. What is the % of carbon in the hydrocarbon?Group of answer choices15.9%80.2 %16.8 %83.2%84.1 %

To solve this problem, we need to use the concept of stoichiometry and the fact that the mass of carbon in the hydrocarbon is equal to the mass of carbon in the carbon dioxide produced.

Step 1: Determine the molar mass of carbon dioxide (CO2). The molar mass of carbon (C) is approximately 12.01 g/mol and the molar mass of oxygen (O) is approximately 16.00 g/mol. Since there are two oxygen atoms in CO2, the molar mass of CO2 is 12.01 g/mol + 2(16.00 g/mol) = 44.01 g/mol.

Step 2: Determine the number of moles of CO2 produced. The number of moles is equal to the mass divided by the molar mass. So, the number of moles of CO2 is 77.0 g / 44.01 g/mol = 1.75 mol.

Step 3: Determine the mass of carbon in the CO2. Since each molecule of CO2 contains one atom of carbon, the number of moles of carbon is equal to the number of moles of CO2. Therefore, the mass of carbon is 1.75 mol * 12.01 g/mol = 21.02 g.

Step 4: Determine the percentage of carbon in the hydrocarbon. The percentage is equal to the mass of carbon divided by the total mass of the hydrocarbon, multiplied by 100%. So, the percentage of carbon is (21.02 g / 25.0 g) * 100% = 84.1%.

So, the correct answer is 84.1%.