Question

How many grams of carbon are in a 100 gram sample of decane? Your answer should have the appropriate number of significant figures (use two decimal places in atomic masses). Only give the numeric value of your answer. Don't include the units.

Answer 1

To find the grams of carbon in a 100 gram sample of decane, calculate the molar mass of decane, determine the percentage of carbon, and apply this percentage to the sample mass. The result, respecting significant figures, is 84.21 grams of carbon.

Step-by-step explanation:

To calculate the grams of carbon in a 100 gram sample of decane, we need to know the molecular formula of decane, which is C10H22.

Firstly, we calculate the molar mass of decane using the atomic masses of carbon (12.01 g/mol) and hydrogen (1.008 g/mol). The molar mass of decane C10H22 is:
(10 × 12.01 g/mol) + (22 × 1.008 g/mol) = 142.28 g per mole of decane.

Now, we calculate the percentage of carbon in decane by:
(mass of carbon / molar mass of decane) × 100 =
(10 × 12.01 g/mol / 142.28 g/mol) × 100 = 84.21%.

The mass of carbon in a 100 gram sample of decane is:
84.21% of 100 grams = 84.21 grams.

Following the rules of significant figures, the final value is rounded to two decimal places.