How many molecules of ethane (C2H6) are present in 0.524 g of C2H6?
(0.524 g C2H6)*(1 mol/ "molar mass" C2H6)*("Avogrado's number" molecules/1 mol)
notice that all my units are canceled except for molecules
To calculate the number of molecules of ethane (C2H6) present in 0.524 g, we need to follow these steps:
Step 1: Calculate the molar mass of ethane (C2H6).
Ethane (C2H6) is made up of 2 carbon atoms (C) and 6 hydrogen atoms (H). The atomic masses of carbon and hydrogen are approximately 12.01 g/mol and 1.01 g/mol, respectively.
Molar Mass of C2H6 = (2 * Atomic Mass of C) + (6 * Atomic Mass of H)
= (2 * 12.01 g/mol) + (6 * 1.01 g/mol)
= 24.02 g/mol + 6.06 g/mol
= 30.08 g/mol
Step 2: Determine the number of moles of ethane (C2H6).
To find the number of moles, divide the given mass (0.524 g) by the molar mass determined in Step 1.
Number of moles = Mass (g) / molar mass (g/mol)
= 0.524 g / 30.08 g/mol
≈ 0.0174 mol
Step 3: Use Avogadro's number to convert from moles to molecules.
Avogadro's number is approximately 6.022 x 10^23 molecules/mol.
Number of molecules = Number of moles * Avogadro's number
= 0.0174 mol * 6.022 x 10^23 molecules/mol
≈ 1.05 x 10^22 molecules
Therefore, there are approximately 1.05 x 10^22 molecules of ethane (C2H6) present in 0.524 g of C2H6.