Реферат: Rate Of Reaction In Sodium Thiosulphate And
Effects of a temperature change – The graph below shows Maxwell-Boltzmann
distribution graphs for a fixed mass of gas at two temperatures ? T1 and T2,
where T2 is roughly 10°C higher than T1. The total area under the curve remains
the same, since there is no change in the number of particles present.
A small increase in temperature causes significant changes to the distribution
energies. At the higher temperature:
1. The peak is at a higher energy.
2. The peak is lower.
3. The peak is broader.
4. There is a large increase in the number of particles with higher energies.
It is the final change that results increase in rate, even with a relatively
small increase in temperature. A small increase in temperature greatly
increases the number of particles with energy greater than the activation
energy. The shaded areas on the energy distribution curves show this.
Effect of a catalyst – A catalyst works by providing an alternative reaction
pathway that has lower activation energy. A catalyst does not alter the
Maxwell-Boltzmann distribution. Because a catalyst provides a reaction route of
lower activation energy, however, a greater proportion of particles will have
energy greater than the activation energy.
Secondary Sources Used:
AS Level Chemistry Textbook (kinetics module)
The Internet
Dr. Jones?s Chemistry Lessons
Information sheets from Dr. Jones
Obtaining Evidence
Temp.(°C)???????? Time 1 (s)???????? Time 2 (s)??????? Average (s)
20??????????????????? 110.67????????????? 107.42????????????? 109.045
30??????????????????? 100.13????????????? 103.34????????????? 101.735
40??????????????????? 64.20?????????????? 65.92????? ??????????65.06