Moderate

Reactants in a transition state:

Correct answer: C. May return to reactants or proceed to form products

  • A. Always change to product
  • B. Return back to reactants
  • C. May return to reactants or proceed to form products
  • D. Are of low energy

Explanation

The transition state is a high-energy state, and some amount of energy - the activation energy - must be added for the molecule to reach it. Because the transition state is unstable, reactant molecules don't stay there long but quickly proceed to the next step of the chemical reaction. If the molecules in the reactants collide with enough kinetic energy and this energy is higher than the transition state energy, then the reaction occurs, and products form. But if the k.E of colliding molecules is not enough and so transition state then the colliding molecules just bounce back unchanged.

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About Reaction Kinetics

Reaction kinetics relates reaction rate to concentration, temperature, surface area and catalysts. Questions cover rate laws, reaction order, rate constants, activation energy and the activated complex, including how a catalyst lowers the activation energy without changing the overall energy change or equilibrium position.

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