When conditions change, the rate of chemical reaction changes

Without the intrinsic factors, you can't change it.

In the section on learning reaction rate, the focus is on the change of reaction rate after the conditions change, how to quickly understand and answer such questions?

There are five factors that affect the reaction rate: temperature, pressure, concentration, catalyst, and contact area, of which the contact area is for solids and is not discussed at the high school level. The other four, in which the temperature increase is to increase the degree of molecular activation, so that more molecules can cross the activation energy to accelerate the reaction rate, the catalyst is to reduce the activation energy, so that more molecules can be activated to accelerate the reaction rate, and the pressure and concentration are to increase the reaction rate by increasing the amount of the unit volume of the substance, increasing the contact area.

This is the essential difference between the four influencing factors.

In addition, the reaction rate is divided into positive reaction rate and reverse reaction rate, which are always in a state where one increases and the other decreases, and finally equals and reaches an equilibrium state.

Therefore, after reaching the equilibrium state, the conditions are changed, and the reaction rate changes for the first time, which is the change caused by the conditions, such as increasing the temperature, the forward and reverse reaction rates are increased, which is the change of the conditions at this moment, and then, if the reaction is carried out in the direction of the positive reaction, the positive reaction rate will decrease, because the influencing factor after crossing the node is no longer the temperature increase, but the change of concentration, as the reaction proceeds in the direction of the positive and negative brothers, the concentration of reactants decreases, and the positive reaction rate decreases. As the concentration of the product increases, the positive reaction rate increases.

For example: n2(g)+3h2(g)==2nh3(g) h<0

After the reaction reaches equilibrium, when the pressure is increased, at this moment, the rate of forward and reverse reactions is increasing, which is the effect of pressure, and then, the effect of instantaneous pressure has ended, and the next thing that comes into play is the concentration. According to Lechatelier's principle, the reaction proceeds in the direction of positive reaction, and as the reaction progresses, the amount of N2 and H2 decreases, the rate of positive reaction decreases, the amount of NH3 increases, and the rate of reverse reaction increases.

Therefore, it is very simple to draw the positive reaction rate or the reverse reaction rate separately.

Another issue that needs to be highlighted is:

When the reaction proceeds in the direction of the positive reaction, when the rate of positive reaction represented by N2 decreases, the rate of positive reaction represented by NH3 also decreases hollowly, but the rate of reverse reaction represented by NH3 should increase. This is because the rate of the pure positive reaction or the rate of the reverse reaction is proportional to the coefficient, whether expressed in reactants or products, increasing and decreasing at the same time. Look at the problem in a dichotomy:

The reason is that the concentration of reactants increases, indicating that the reaction proceeds in the direction of the reverse reaction, and the concentration of the product decreases, so the rate of the reverse reaction decreases, and vice versa.

The whole process of rate change is often involved in the concentration, the conditions act in an instant, and the rest is that the concentration causes the change of the whole reaction, and finally reaches the equilibrium state.

Change the rate of chemical reactions.

Factors are: temperature, concentration, pressure, catalyst.

By changing the average kinetic energy of the split molecules, the temperature changes the number of molecules reaching the activated state, thereby changing the reaction rate. Imitation of royal potatoes.

Concentration and pressure by changing the unit volume.

the number of molecules in the body, so that the frequency of the collision required for the reaction changes, thus changing the reaction rate;

The catalyst can be activated directly by changing the reaction energy.

Generally, the reaction rate is changed by changing the reaction mechanism by the preparer. Among them, the positive catalyst decreases the activation energy and increases the rate (the most common), and the negative catalyst increases the activation energy and decreases the rate.

Factors that affect the rate of chemical reactions.

1.The rate of chemical reaction is determined by the aluminous properties of the reactants--- internal factors are the main cause.

2.Effect of catalyst on the rate of chemical reactions.

Catalysts can change the rate of chemical reactions.

3.Effect of temperature on chemical or paralytic reaction rate.

As the temperature increases, the rate of chemical reaction increases.

4.Effect of concentration on the rate of chemical reactions.

As the concentration of reactants increases, the rate of chemical reaction increases.

5.Effect of the surface area of a solid reactant on the rate of a chemical reaction.

The surface area of the solid reactants increases, and the chemical reaction rate increases.

Thank you.

What are the conditions that affect the rate of chemical reactions, and what are the comprehensive.

Expression: v(a) = c(a) t

Unit: mol (l·s) or mol (l·min) Factors that affect the rate of chemical reactions: temperature, concentration, pressure, catalyst.

In addition, X-rays, radiation, and the surface area of solid matter also affect the rate of chemical reactions.

The formula for calculating a chemical reaction:

For the following reactions:

ma+nb=pc+qd

Factors that affect the rate of chemical reactions.

1.The rate of chemical reaction is determined by the nature of the reactants--- internal factors are the main causes2Effect of catalyst on the rate of chemical reactions.

Catalysts can change the rate of chemical reactions.

3.Effect of temperature on the rate of chemical reactions.

As the temperature increases, the rate of chemical reaction increases.

4.Effect of concentration on the rate of chemical reactions.

As the concentration of reactants increases, the rate of chemical reaction increases.

5.The effect of the surface area of the solid reactants on the chemical reaction rate increases, and the surface area of the solid reactants increases, and the chemical reaction rate increases.

According to the coefficient, the pressure is increased by the reaction without the participation of gas.

Let's start with the rate of chemical reactions. There are several main factors. First.

Temperature. The rate of reaction is accelerated when the temperature increases. Second.

Concentration. The concentration depends on whether the concentration of the reactant or the concentration of the product is added. The instantaneous positive reaction rate of increasing the concentration of reactants becomes faster and the reverse reaction rate remains the same (vice versa), which can be understood by drawing. Third.

The essence of changing pressure is actually changing the concentration. However, as the image shows that the reverse reaction rate and the positive reaction rate are accelerated when the pressure is increased.

The limits of reversible reactions. Even the balance of moving that piece is also a few factors. Temperature – The temperature rises in the direction of the endothermic reaction. The temperature drop is like the direction of exothermy.

Pressure – The pressure increases. Go to the side with the gas coefficient low (you increase the pressure.) But it can't grow so fast. What to do, I have to make it produce less gas).

Secondly, as the concentration increases, the concentration equilibrium of the reactants shifts in the direction of the positive reaction (and vice versa).

That's pretty much it.

Temperature: In general, the higher the temperature of the system, the greater the rate.

Concentration: Usually the higher the concentration, the greater the reaction rate, but only if the reactant is a solution, a gas, generally if it is water, solid and the like.

There is no concentration at all.

Pressure: Usually the higher the pressure of the reaction with the participation of gas, the greater the rate, if there is no gas involved in the reaction, it is not applicable.

Therefore, temperature, concentration, and pressure do not necessarily affect the rate of chemical reactions.

Simply put, these are the external conditions of the chemical reaction, and the conditions that affect the rate of the chemical reaction are also related to the concentration of the catalyst reactants.

Pressure: For chemical reactions with gas participation, when other conditions remain unchanged (except volume), increase the pressure, that is, the volume decreases, the concentration of reactants increases, the number of activated molecules per unit volume increases, the number of effective collisions per unit time increases, and the reaction rate accelerates; Otherwise, it decreases. If the volume is constant, the rate of the pressurized reaction (adding gases that do not participate in this chemical reaction) will not change.

Because the concentration does not change, the number of activated molecules per unit volume does not change. However, when the volume remains the same, the reactants are added, which is also pressurized, and the concentration of reactants is increased, and the rate will also increase.

Temperature: As long as the temperature is raised, the reactant molecules gain energy, so that a part of the original low energy molecules become activated molecules, which increases the percentage of activated molecules, so that the number of effective collisions increases, so the reaction rate increases (the main reason). Of course, as the temperature increases, the rate of molecular motion accelerates, and the reaction will increase as the number of molecular collisions of reactants per unit time increases

Catalyst: The use of positive catalyst can reduce the energy required for the reaction, so that more reactant molecules become activated molecules, which greatly increases the percentage of reactant molecules per unit volume, thereby increasing the reactant rate thousands of times. Negative catalysts are the opposite.

Concentration: When other conditions are consistent, increasing the concentration of reactants increases the number of activated molecules per unit volume, thereby increasing the effective collision and increasing the reaction rate, but the percentage of activated molecules is unchanged.

The positive catalyst of the catalyst accelerates the positive reaction rate.

The temperature depends on the reaction, generally the higher the temperature, the faster the reaction.

The greater the concentration of reactants, the faster the reaction.

The gaseous state is first of all constant temperature to ensure that the temperature does not affect the rate

When the capacity is constant, the volume of the container remains unchanged, and the inert gas is filled with inert gas, which does not participate in the reaction, and the amount of gaseous substances participating in the reaction does not change, so the concentration does not change, and the rate does not change

At constant pressure, the amount of the substance becomes larger when the reaction gas is charged, and the volume becomes larger in order to maintain the constant pressure, so the concentration remains the same and the rate remains the same.

The larger the solid reactant surface, the faster the reaction!

Hope landlord !!

Concentration: Increase the concentration of reactants, and the reaction rate is accelerated.

Pressure: For gas reactions, increasing the pressure (reducing the volume of the vessel) is equivalent to increasing the concentration of reactants and accelerating the reaction rate.

Temperature: Increasing the temperature increases the reaction rate.

Catalyst: Generally can speed up the rate The number of words is limited, and on the contrary, there is no land.

The catalyst is one of these factors.

The external conditions that affect the chemical reaction rate are mainly the rapid reaction of increased temperature, the fast reaction of large reactant concentration, the fast reaction of high pressure (gas reaction), the accelerated reaction of catalyst, and the fast reaction of small reactant particles. In addition, there is light (such as lasers, which are effective in reacting to parts), ultrasound (similar to light), etc.

Temperature, concentration, pressure, catalyst, contact area, etc., all have reaction ......