Question

This is from an experiment simulating a breathalyzer. Potassium dichromate standard is 0.625 mg/mL in 9M sulfuric acid. We are using the equation 3 C2H5OH + 2 K2Cr2O7 + 8 H2SO4 → 3 CH3COOH + 2 Cr2(SO4)3 + 2 K2SO4 + 11 H2O for the reaction of dichromate and ethanol.

Operating wavelength : 436 nm
Absorbance of solution 1 (10.0 mL Standard Dichromate and 1.00 mL H₂O) : 0.577 a.u.
Absorbance of solution 2 (10.0 mL Standard Dichromate and 1.00 mL ethanol standard) : 0.445 a.u.
Absorbance of solution 3 (10.00 mL Standard Dichromate and 1.00 mL simulated ethanol DWI sample) : 0.438 a.u.
Mass of dichromate in Solution 1 : 6.25 mg
Mass of dichromate in Solution 2: 4.820 mg
Mass of dichromate in Solution 3: 4.744 mg

For solutions 2 and 3, what is the mass of dichromate consumed, the moles of dichromate consumed, the moles of ethanol consumed, and the mass of ethanol consumed?

Answer 1