Practicing Success

Target Exam

CUET

Subject

Chemistry

Chapter

Physical: Chemical Kinetics

Question:

The rates of most reactions double when their temperature is raised from 298 K to 308 K. Calculate their activation energy. [R = 8.314 JK-1 mol-1]

Options:

52.905 kJ mol-1

42.905 kJ mol-1

62.905 kJ mol-1

72.905 kJ mol-1

Correct Answer:

52.905 kJ mol-1

Explanation:

log\(\frac{K_2}{K_1}\) = \(\frac{E_a}{2.303R}\)[\(\frac{1}{T_1}\) - \(\frac{1}{T_2}\)]

let K1 = x and K2 = 2x

log\(\frac{2x}{x}\) = \(\frac{E_a}{19.15}\)[\(\frac{1}{298}\) - \(\frac{1}{308}\)]

log2 = \(\frac{E_a}{19.15}\)[\(\frac{1}{298}\) - \(\frac{1}{308}\)]

0.30 = \(\frac{E_a}{19.15}\)[\(\frac{308 - 298}{298×308}\)]

Ea = 52905 J mol-1 = 52.905 kJ mol-1