This model demonstrates an energetic background of the process of chemical catalysis. The graph represents a conventional curve of the dependence of reagent energy on a progress of reaction. The potential barrier prevents the progress of reaction under low temperature when the energy of thermal motion is insufficient to overcome it. By use of spin box located in the low part of the model you may change temperature. You may make certain that the model reaction may proceed without catalyst under the highest temperature the only. In the presence of catalyst the energy barrier either decreases essentially or disappears entirely and thus the rate of reaction substantially increases. To observe in this model how the reaction proceeds in the presence of catalyst, click the button marked as "Catalyst" (it is available until the process of reaction is initiated). To initiate the reaction, press the "Start" button. The "Stop" and "Reset" button are aimed to stop reaction and to fix the model in initial position, respectively. A column diagram in the window on the right side of the window of reaction shows the current amounts of the reaction components (initial compounds and products).