Question

Ethanol has the chemical formula C2 H6 O . A sample of ethanol contains 164grams of C. How many molecules are in the sample? (4.11E24 molecules C2 H6 O

Answer 1

We have 8.22 * 10^24 C atoms

We have 4.11 * 10^24 ethanol molecules

Step-by-step explanation:

Step 1: Data given

Molecular formula of ethanol = C2H6O

Mass of C = 164 grams

Molar mass C = 12.01 g/mol

Step 2: Calculate moles C

Moles C = mass C / molar mass C

Moles C = 164 grams / 12.01 g/mol

Moles C = 13.66 moles

Step 3: Calculate molecules of C

Atoms C = moles C * number of Avogadro

Atoms C = 13.66 moles * 6.02 * 10^23 molecules/ mol

Atoms C = 8.22 * 10^24 C atoms

Step 4: Calculate molecules in the sample

For 1 mol C2H6O we have 2 moles C

For 13.66 moles C we have 13.66/ 2 = 6.83 moles C2H6O

Molecules C2H6O = 6.83 moles * 6.02 * 10^23 = 4.11 *10 ^24 molecules