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Rate Of Reaction In Sodium Thiosulphate And (стр. 2 из 2)

Collisions between reacting particles are therefore more likely to occur.

The graph for concentration shows that when the concentrations were relatively

low (10, 15, 20 g/dm3), the increase of rate x1000 was also fairly small

(increasing from 4.47 to 6.71 to 9.47). There was then a gradual increase in

the difference, and between 30 and 35 g/dm3 the rate more than doubled from

17.90 to 37.56s-1. This shows that there are far more collisions at a

concentration of 35 g/dm3 than at 30 g/dm3.

The graph plotting time against the rate of reaction x1000 shows that the

difference of rate between increasing temperatures (excluding the anomaly of

30°C) was pretty much regular, increasing in steps of 6-10 (9.17 to 15.37 to

24.28 to 31.67). However, once again there is a giant gap in the last

temperature increase ? at 60°C the RoR x1000 is 31.67 s-1, and at 70°C it is

57.03 s-1.

For this to fully make sense it is necessary to recap the collision theory

briefly:

For a reaction to occur particles have to collide with each other. Only a small

percent result in a reaction. This is due to the energy barrier to overcome.

Only particles with enough energy to overcome the barrier will react after

colliding. The minimum energy that a particle must have to overcome the barrier

is called the activation energy, or Ea. The size of this activation energy is

different for different reactions. If the frequency of collisions is increased

the rate of reaction will increase. However the percent of successful

collisions remains the same. An increase in the frequency of collisions can be

achieved by increasing the concentration, pressure, or surface area.