Question

How many molecules of C2H5OH are in 0.238mol of C2H5OH?

Answer 1

Explanation:

Start by writing a balanced equation

CH3CH2OH + 3 O2 → 2CO2 + 3H2O

1 mol CH3CH2OH reacts with 3 mol O2 to produce 3 mol H2O

Mass of ethanol reacted = 4.63 mL * 0.789 g/mL = 3.653 g

molar mass CH3CH2OH = 46,07 g/mol

mol ethanol reacted = 3.653 g / 46.07 g/mol = 0.0793 mol

This will react with 0.0793 mol * 3 = 0.238 mol O2

molart mass O2 = 32 g/mol

Mol O2 in 15.35 g = 15.35 g/ 32 g/mol = 0.479 mol O2

The O2 is in excess - the CH3CH2OH is limiting.

0.0793 mol CH3CH2OH will produce 3*0.0793 = 0.238 mol H2O

Molar mass H2O = 18 g/mol

Mass of 0.238 mol H2O = 0.238 mol * 18 g/mol = 4.28 g H2O Theoretical Yield

But 3.7 mL = 3.70 g H2O was recoverd

% yield = 3.70 g / 4.28 g * 100% = 86.4 % yield ( 3 significant digits)