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For the decomposition reaction 2N2O5 → 4NO2 + O2, the rate and the rate constant are 1.02 × 10⁻⁴ mol L⁻¹ s⁻¹ and 3.4 × 10⁻⁵ s⁻¹, respectively. What is the concentration of N2O5 at that instant?

1. 1.732 M
2. 3 M
3. 3.4 × 10⁵ M
4. 1.02 × 10⁻⁴ M

Correct answer: 3 M

Solution

For first-order decomposition, rate = k[N2O5], so [N2O5] = rate/k = (1.02 x 10^-4)/(3.4 x 10^-5) = 3 M.

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