activation energy barriers

Energy Barrier - In this theory, the rate constant is related to three factors Z, f and p by the equation k = Zfp b (19) where Z is the collision frequency f is the fraction of collisions having energy greater than the threshold energy and p is the fraction o..

. Collision theory explains the temperature dependence of rate of a reaction based specifically on the concept of effective collisions. However, collision theory does not account for the role of activation energy influencing the rate of a reaction. Another theory that was propos..

In this theory, the rate constant is related to three factors Z, f and p by the equation k = Zfp..

Concept of Activation Energy - For a reaction to occur, reactant molecules must collide with each other. Only those collisions result in product formation which have energy equal or more than a certain minimum energy. This energy is called the thres..

Collision Theory - From Arrhenius equation, it is seen that the rate constant k of a reaction increases with temperature and therefore, the rate of reaction also increases. Why does k depend on temperature? This can be explained, to a certain extent, by collision theory. According to this theory, a..

Active Absorption - Movement of ions from the outer space of the cell to the inner space is generally against the concentration gradient and hence requires energy. This energy is obtained through metabolism either directly or indirectly. Various evidences indicate the ..

The transport of materials across the cell membranes with the help of energy is called active transport. Both diffusion and osmosis are passive transport mechanisms, not requiring energy. Active transport helps in the transport of ions across the membranes of..

Movement of ions from the outer space of the cell to the inner space is generally against the concentration gradient and hence requires energy. This energy is obtained through metabolism either directly or indirectly. Various evidences indicate the active uptake ..

This process is much faster and requires energy. A membrane pump operates across the cell membranes which transports the nutrients from the lumen of the intestine into the cells. This transport occurs with the help of ATP molecules. The carrier proteins in the membrane act as ATPases and..