Which of the following statements is FALSE?

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BlackTom AI · Accepted Answer

Question restatement: Which of the following statements is FALSE?

Option A: 'Chemical reactions progress at a faster rate when the reacting particles are present in higher concentration.' This is generally true because higher concentration increases the number of collisions between reactant molecules, raising the likelihood of successful reactions and thus the rate.

Option B: 'Catalysts increase the rate of chemical reactions, sometimes while undergoing reversible changes in shape.' This is true. Catalysts provide an alternative reaction pathway with a lower activation energy, and many catalysts work by changing shape during the process before returning to their original form; these changes can be reversible.

Option C: 'Larger particles move faster than smaller ones and thus collide more frequently and more forcefully.' This is false under typical gas-phase kinetics. At a given temperature, all gas particles have (on average) the same kinetic energy, but their speeds are inversely related to the square root of their masses. Therefore, larger (more massive) particles move more slowly than smaller ones, not faster. Consequently, they collide less frequently and with less force on average, not more.

Option D: 'Chemical reactions proceed more quickly at higher temperatures.' This statement is true because increasing temperature raises the average kinetic energy of molecules, leading to more energetic collisions and more molecules surpassing the activation energy barrier.

Option E: 'Chemical reactions proceed faster at higher temperatures, presence of catalysts and in increased solute concentrations' This is generally true as a combination: higher temperature and catalysts both raise reaction rates, and in solutions, higher solute concentrations can increase collision frequency or change the reaction environment to favor faster rates.

Overall assessment: Options A, B, D, and E describe factors known to increase reaction rates and are correct in standard kinetic and catalysis principles. Option C makes a claim opposite to the fundamental kinetic fact that, at the same temperature, smaller particles tend to have higher speeds than larger particles due to mass differences, and thus larger particles do not move faster and do not necessarily collide more forcefully. This misrepresents molecular speed–mass relationships and collision dynamics, making it the false statement.

Which of the following statements is FALSE?

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