Practice AP Chemistry Unit 5.5 questions on connecting collision frequency, particle energy, activation energy, temperature, and surface area to reaction rate.
A chemical reaction between maleic acid (H2C4H2O4) and sodium bicarbonate (NaHCO3) occurs in the presence of water to produce carbon dioxide and sodium maleate (Na2C4H2O4), as represented by the following equation.
The student performs a second experiment that is identical to the first except that the student grinds the chunks of H2C4H2O4(s) and NaHCO3(s) into powder before combining the powder with water.
The rate-determining step for the overall reaction is the dissolving of the solids. Would the time required for the dissolving of the solids in the second experiment be longer than, shorter than, or the same as the time required in the first experiment? Justify your answer based on the collisions between particles.
For the correct answer and a valid justification: 1 point
Shorter than. The powdered solids have a larger surface area than the solid chunks, thus collisions between water and the surface particles occur more frequently, resulting in a faster rate of dissolution and a shorter amount of time to dissolve the solids.