Temperature coefficient = k_$\frac{T+10}{k_T}$, typically 2-3 for most reactions near room temperature. Even a small temperature increase dramatically affects rate because the fraction of molecules with E >= Ea increases exponentially: fraction = e^(-Ea/RT). A 10 K increase from 300 to 310 K: the Boltzmann factor e^(-Ea/RT) can increase by 2-4x for Ea ≈ 50-100 kJ/mol. The Maxwell-Boltzmann distribution curve shifts right and flattens with increasing T — more molecules populate the high-energy tail. This exponential sensitivity to temperature is why Arrhenius kinetics is so important. For biological reactions: Q10 (the 10-degree coefficient) is typically 2-3; enzymes may denature above ~60 C, causing rate to drop.