Final answer:
To calculate the number of carbon atoms in a propane sample given the number of hydrogen atoms, divide the amount of hydrogen atoms by 8 (the number of H atoms in each propane molecule) and then multiply the result by 3 (the number of C atoms per propane molecule).
Step-by-step explanation:
The question asks about determining the number of carbon atoms in a sample of C₃H₈ (propane) given the number of hydrogen atoms present. To answer this question, we need to utilize the molecular formula of propane, which indicates there are 8 hydrogen atoms per molecule of C₃H₈. Given that there are 7.20×10²⁴ H atoms in the sample, we can divide this number by 8 to find the number of propane molecules, since each molecule contains 8 hydrogen atoms.
For example, suppose we know that one mole of any element or compound equals 6.02 x 10²³ entities (atoms, molecules, etc.). Therefore, the number of moles of C₃H₈ present would then be the number of molecules divided by Avogadro's number (6.02 x 10²³). Finally, since each propane molecule contains 3 carbon atoms, we would multiply the number of moles by 3 to find the total number of carbon atoms.