How do I compare the size of a chemical reaction rate?

There are generally two ways to compare the magnitude of chemical reaction rates: 1: Convert to the same unit, unify the reaction rate of the substance, and directly compare the size.

2: For equation aa + bb == cc, find: v(a):

The value of v(b) is compared to the value of a:b, if v(a):v(b)==a:

b The rate is equal; if: v(a):v(b) a:

b，v(a)＞v(b）；v(a):v(b)＜a:b，v(a)＜v(b）。

When the same chemical reaction rate is expressed by different substances, the values may be different, and the speed of comparing the chemical reaction rate can not only look at the size of the value, but also carry out a certain transformation: convert to the same substance, the same unit representation, and then compare the value size.

For example, the reversible reaction A+3B=2C+2D, the fastest reaction rate under different conditions is ( ).

a．v(a)= b．v(b)=

c．v(c)= d．v(d)=

After conversion, v(a)=in a, v(a)=, v(a)=, v(a)=, and v(a)=6mol (l·min) in d, the answer is d.

The easiest way is to divide the rates of different substances by the coefficients, and the larger is the faster.

The chemical reaction rate is the amount of change in the reactants or products of the reaction per unit time, and it must be noted that the same substance should be noted when comparing.

Of course, the powder form is fast, and chemical tests have shown that the temperature increases by 5 degrees, and the rate is doubled, so the lumpy form is due to the high temperature, and the lumpy form.

Compared with the temperature of 35, the rate is 2*2*2=8 times, and the ratio of powdered surface area to bulk surface area is much greater than 8, so the powder is fast.

Scheme 2, because this is an exothermic reaction, the higher the temperature, the slower the reaction rate. At the same time, the reaction rate of the powder form is also faster than that of the bulk form because of the large contact area of the molecules.

It's a really difficult question, and I can't do it, but to correct a mistake. The reaction rate has nothing to do with whether the reaction is exothermic or not, so don't confuse the balance problem with the rate problem. As for which one has the fastest reaction rate, I can only say that there is no condition for this topic.

How much is lumpy than the surface? How big is the powdered form than the surface?

The rate of the same chemical reaction.

The value may be different when it is expressed by different substances in the bond town, and the speed of comparing the chemical reaction rate can not only look at the value size, but also carry out a certain transformation: convert it into the same substance, the same unit representation, and then compare the value size of the bright source Qing state.

For example, the reversible reaction A+3B=2C+2D, the fastest reaction rate under different conditions is ( ).

a．v(a)= b．v(b)=

c．v(c)= d．v(d)=

After conversion, v(a)=in a, v(a)=, v(a)=, v(a)=, and v(a)=6mol (l·min) in d, the answer is d.

The main factors that affect the rate of a chemical reaction include concentration, pressure, temperature, catalyst, and many more.

1. Concentration of group bending: increasing the concentration of reactants can increase the rate (excluding solids and pure liquids, the concentration of the two is a constant, and the rate will not change when increasing);

2. Pressure: For reactions with gas participation, when the volume is constant, increasing the pressure can speed up the rate, and it does not include solids and pure liquids;

3. Temperature; Increase the temperature, increase the rate, decrease the temperature, decrease the rate;

4. Catalyst: The positive catalyst can increase the reaction rate, and the negative catalyst can slow down the rate.

The rate of a chemical reaction is an indication of how fast a chemical reaction proceeds. It is usually expressed as the change value (reduction value or added value) of the concentration of reactants or products per unit time, and the reaction speed is related to the nature and concentration of the reactants, temperature, pressure, catalyst, etc., and if the reaction is carried out in solution, it is also related to the properties and amount of solvents. Among them, the pressure relationship is small (except for gas reaction), and the influence of catalyst is greater.

The rate of reaction can be controlled to achieve certain purposes by controlling the reaction conditions.

The ratio of the rate of the same chemical reaction represented by different substances is equal to the ratio of stoichiometric numbers. This formula is used to determine the stoichiometric number and compare the speed of the reaction, which is very practical.

The rate of the same chemical reaction is expressed by the change in the concentration of different substances, and the values are different, so the substance must be specified when expressing the rate of chemical reaction.

Effect of external conditions on the rate of chemical reactions:

1) The concentration of pure liquids and solids is considered constant, and the change in their amount does not affect the rate of chemical reactions. However, the size of the particles causes the size of the contact area to change, so the reaction rate is affected.

2) Solid and liquid substances, since the pressure changes have little effect on their volume, so the effect of pressure on their concentration can be regarded as constant, and the pressure has no effect on the rate of chemical reactions without the participation of gases.

3) The increase in temperature increases whether it is an endothermic reaction or an exothermic reaction, and whether it is a positive reaction rate or a reverse reaction rate.

4) For chemical reactions with the participation of gases, there are the following cases:

At constant temperature: compressing the volume of the reaction system leads to an increase in the induced pressure, which in turn leads to an increase in the concentration of reactants, which in turn leads to an increase in the reaction rate.

At constant temperature, for constant volume closed containers:

a.The filling of gas reactants leads to an increase in the concentration of gas reactants (as well as an increase in pressure), which leads to an increase in the reaction rate.

b.The addition of "inert" gas causes an increase in the total pressure of the gas, but the concentration of the gas reactants does not change, so that the reaction rate does not change.

At constant temperature and pressure: the filling of "inert" gas causes the volume of the reaction system to increase, which in turn causes the concentration of gas reactants to decrease, which leads to a decrease in the reaction rate.

5) When other things being equal, the chemical reaction rate is accelerated by using a catalyst.

6) In addition, light waves, electromagnetic waves, ultrasonics, solvents, etc. can also affect the rate of chemical reactions.

For reversible reactions, it is impossible to judge, because the reaction rate increases with the increase of temperature, and many strong endothermic reaction rate constants are very large, for reversible reactions, because the positive reaction rate constant divided by the reverse reaction rate constant is the equilibrium constant, so if the effect of the increase of the positive reaction rate constant after the temperature increases is greater than the effect of the increase of the reverse reaction rate constant, the reaction is endothermic (the equilibrium constant increases), and vice versa.

Factors influencing the rate of chemical reactions: main factors: properties of the reactants themselves, external factors: temperature, concentration, pressure, catalyst, light, laser, reactant particle size, contact area between reactants and reactant state.

The size of the rate can be judged according to the difference in each condition.

For reversible reactions, it is impossible to judge because the reaction rate increases with the increase of temperature, and many strong endothermic reaction rate constants are very large, for reversible reactions, because the positive reaction rate constant divided by the reverse reaction rate constant is the equilibrium constant, so if the effect of the increase of the positive reaction rate constant after the temperature rises is greater than the effect of the increase of the reverse reaction rate constant, the reaction is endothermic (the equilibrium constant increases), and vice versa.