The reaction that occurs in a breath analyzer, a device used to determine the alcohol level in a per — Chemical Kinetics Chemistry Question
Question
The reaction that occurs in a breath analyzer, a device used to determine the alcohol level in a person's blood stream is: 2K Cr O + 8H SO + 3C H O 2Cr (SO ) + 3C H O + 2K SO + 11H O If the rate of appearance of Cr (SO ) is 2.67 mol min at a particular time, the rate of disappearance of C H O at the same time is ________ mol min . (Nearest integer) 2 2 7 2 4 2 6 2 4 3 2 4 2 2 4 2 2 4 3 –1 2 6 –1
💡 Solution & Explanation
**Step 1: Identify the balanced equation coefficients** From the equation: 2K₂Cr₂O₇ + 8H₂SO₄ + 3C₂H₆O → 2Cr₂(SO₄)₃ + 3C₂H₄O + 2K₂SO₄ + 11H₂O Coefficient of Cr₂(SO₄)₃ = 2 Coefficient of C₂H₆O = 3 **Step 2: Apply stoichiometric relationship** For any reaction: rate relationships are determined by the stoichiometric coefficients. $$\frac{\text{Rate of appearance of Cr}_2(\text{SO}_4)_3}{2} = \frac{\text{Rate of disappearance of C}_2\text{H}_6\text{O}}{3}$$ **Step 3: Substitute the given rate** Rate of appearance of Cr₂(SO₄)₃ = 2.67 mol/min $$\frac{2.67}{2} = \frac{\text{Rate of disappearance of C}_2\text{H}_6\text{O}}{3}$$ **Step 4: Solve for the unknown rate** $$\text{Rate of disappearance of C}_2\text{H}_6\text{O} = \frac{2.67 × 3}{2}$$ $$= \frac{8.01}{2} = 4.005 \text{ mol/min}$$ **Step 5: Round to nearest integer** 4.005 ≈ 4.00 mol/min Therefore, the answer is **4.00**.