2NO + 2H → N + 2H O The above reaction has been studied at 800°C. The related data are given in the — Chemical Kinetics Chemistry Question
Question
2NO + 2H → N + 2H O The above reaction has been studied at 800°C. The related data are given in the table below Reaction serial number Initial pressure of H /kPa Initial Pressure of NO/kPa Initial rate 1 65.6 40.0 0.135 2 65.6 20.1 0.033 3 38.6 65.6 0.214 4 19.2 65.6 0.106 The order of the reaction with respect to NO is____ 2 2 2 2
💡 Solution & Explanation
**Step 1: Identify the rate law form** For the reaction, the rate law is: Rate = k[NO]^m[H₂]^n We need to find m (the order with respect to NO). **Step 2: Select two experiments where H₂ concentration is constant** Compare Experiments 1 and 2 (both have [H₂] = 65.6 kPa): - Exp 1: [NO] = 40.0 kPa, Rate = 0.135 - Exp 2: [NO] = 20.1 kPa, Rate = 0.033 **Step 3: Set up the ratio of rates** $$\frac{\text{Rate}_1}{\text{Rate}_2} = \frac{k[NO]_1^m}{k[NO]_2^m} = \left(\frac{[NO]_1}{[NO]_2}\right)^m$$ $$\frac{0.135}{0.033} = \left(\frac{40.0}{20.1}\right)^m$$ **Step 4: Calculate the ratio** $$4.09 ≈ (1.99)^m ≈ (2)^m$$ **Step 5: Solve for m** $$4 ≈ 2^m$$ $$2^2 = 2^m$$ $$m = 2$$ Therefore, the order of the reaction with respect to NO is **2**.