Final answer:
To find the number of moles of C2H6 in a 63.5g sample, you calculate the molar mass of C2H6, which is 30.07 g/mol, and then divide the mass of the sample by the molar mass, resulting in 2.11 moles of C2H6.
Step-by-step explanation:
To determine the number of moles of C2H6 in a 63.5g sample, you use the molar mass of ethane, C2H6. The molar mass is the sum of the masses of all the atoms in one mole of the compound. For C2H6, the molar mass is as follows: (2 × mass of carbon) + (6 × mass of hydrogen) = (2 × 12.01 g/mol) + (6 × 1.008 g/mol) = 30.07 g/mol. With the molar mass calculated, divide the given mass of the sample by the molar mass to find the number of moles:
Number of moles = Mass of sample ÷ Molar mass
Number of moles = 63.5 g ÷ 30.07 g/mol
Number of moles = 2.11 mol (rounded to two decimal places)
Therefore, there are 2.11 moles of C2H6 in the 63.5g sample.