Question

In the PhET Reactions & Rates (http://openstaxcollege.org/l/16PHETreaction) interactive, use the “Many Collisions” tab to observe how multiple atoms and molecules interact under varying conditions. Select a molecule to pump into the chamber. Set the initial temperature and select the current amounts of each reactant. Select “Show bonds” under Options. How is the rate of the reaction affected by concentration and temperature?

Short answer

Rate of reaction increases with increase in temperature and concentration.

Step-by-step solution

Effect of concentration

On increasing the concentration of reactant molecules, the reaction rate increases because the reaction rate is directly proportional to the concentration of reactant. A higher concentration of reactant will lead to more collisions of that reactant in a specific time period.

Rate law predicts the relationship between the rate of reaction and the concentration of reactant.

rate = k [reactant]ⁿ

Temperature

With the increase in temperature, the particle average velocity increases. The average kinetic energy of particles is also increased. The result is that the particle will collide more frequently and move around faster. This results in the encounter of more reactant particles.

Thus, on increasing temperature, the rate of reaction increases because the reactant molecules collide at a faster rate at the high temperature, and their collision results in the formation of products.

At low temperature, molecules have less kinetic energy and less velocity, so their collisions are not much effective to form the product. Hence, the rate of reaction is slow at low temperature.