Chemical Kinetics (continued)

We will now look at some examples. According to the reaction of ammonia synthesis, see the following problem:

Hydrogen gas is consumed at a rate of 18 moles every 4 minutes. Calculate:

a) N consumption speed2

b) the formation rate of the NH3

c) the consumed mass of H2 per minute

d) the mass obtained from NH3 per minute

During a chemical reaction, the concentration of reagents (B) decreases, while the concentration of products increases (A).

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The concentration of reagents may or may not reach zero. If the concentration of the reagents decreases, the reaction speed decreases as well. When the reaction is complete, the speed will be zero.


Consumption and production speed

Average consumption rate is the measure of reagent that is consumed, “disappears” in the reaction, per unit of time.

Average production speed is the measure of product formed during the reaction per unit of time. Be the generic reaction:

In this case, the reagent may also be called a reactor.

The chemical equation can give the stoichiometric coefficient of each reagent. This coefficient represents the number of moles of the substance. See a generic chemical equation where a, b, c and d are stoichiometric coefficients and A, B, C and D it's the chemicals.

Reagent Consumption Speed:


Product formation speed:

Conditions for a chemical reaction to occur

For a chemical reaction to occur, there must be chemical contact and affinity between the reagents. One of the most important conditions for a chemical reaction to occur is activation energy and the collisions between reactant molecules.