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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 :

We have 8.22 [tex]\times[/tex] 1[tex]0^{24}[/tex] C atoms

We have 4.11 [tex]\times[/tex] 1[tex]0^{24}[/tex] ethanol molecules

Explanation:

Step 1: Data given

Molecular formula of ethanol = [tex]C_{2} H_{6} O[/tex]

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 [tex]\times[/tex] number of Avogadro

Atoms C = 13.66 moles [tex]\times[/tex] 6.02 [tex]\times[/tex] 1[tex]0^{23}[/tex] molecules/ mol

Atoms C = 8.22 [tex]\times[/tex] 1[tex]0^{24}[/tex] C atoms

Step 4: Calculate molecules in the sample

For 1 mol [tex]C_{2} H_{6} O[/tex] we have 2 moles C

For 13.66 moles C we have 13.66/ 2 = 6.83 moles [tex]C_{2} H_{6} O[/tex]

Molecules [tex]C_{2} H_{6} O[/tex] = 6.83 moles [tex]\times[/tex] 6.02 [tex]\times[/tex] 1[tex]0^{23}[/tex] = 4.11 [tex]\times[/tex] 1[tex]0^{24}[/tex] molecules.

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