What is the role if a catalyst in a chemical reaction ? define catalyst.?
Answer:
A catalyst is defined as a substance that helps speed up a chemical reaction, however it is not consumed in the reaction.
A catalyst starts a reaction.
A catalyst is chemical that initiates a chemical reaction but is not part of the chemical reaction.
a catalyst is a substance which can alter the rate of a chemical reaction while itself remains chemically unchanged at the end of the reaction. catalyst can be classified into positive catalyst(which increases the rate of reaction) and negative catalyst(which decreases the rate of reaction).a catalyst does not change the quantity of the products formed.
definition & role of a catalyst - a substance that causes or accelerates a chemical reaction without itself being affected
In chemistry and biology, catalysis is the acceleration (increase in rate) of a chemical reaction by means of a substance, called a catalyst, that is itself not consumed by the overall reaction. The word is derived from the Greek noun κατάλυσις, related to the verb καταλύειν, meaning to annul or to untie or to pick up.
A catalyst provides an alternative route of reaction where the activation energy is lower than the original chemical reaction. Catalysts participate in reactions but are neither reactants nor products of the reaction they catalyze. An exception is the process of autocatalysis where the product of a reaction helps to accelerate the same reaction. They work by providing an alternative pathway for the reaction to occur, thus reducing the activation energy and increasing the reaction rate. More generally, one may at times call anything that accelerates a reaction, without itself being consumed or changed, a "catalyst" (for example, a "catalyst for political change").
A good example of a catalyst is in the disproportionation of hydrogen peroxide. Hydrogen peroxide reacts to give water and oxygen gas by itself:
2 H2O2 → 2 H2O + O2
Usually, this reaction is slow. On the addition of manganese dioxide to a dilute solution of hydrogen peroxide, an effervescence is observed, and much oxygen, detectable by a glowing splint, is evolved. The manganese dioxide may be recovered, and re-used indefinitely, thus it is a catalyst — it is not consumed by the reaction.
A promoter is an accelerator of catalysis, but not a catalyst by itself. An inhibitor inhibits the working of a catalyst.
Catalysts are the substances which alters(increase or decrease) the rate of a reaction without undergoing any change.
The catalysts which accelerates the rate of reaction ic called positive catalyst..(vanedium pentoxide in the manufacturing of H2SO4)
The catalysts which slow down the rate of a reaction is called negative catalysts.(glyserine is added to decrease the rate of disintegration of H2O2 in labs)
a substance that initiates a reaction but remains unchanged at the end of the reaction. magnesium oxide serves as a catalyst in the reaction to produce oxygen
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