Loading…
Loading…
GCSE Chemistry · key term
A value used to compare reaction speeds when an exact rate is not calculated; for a fixed endpoint it can be represented by .
Used by OCR
Specification CM5.2i, CM5.3i · Paper 2 (Foundation), Paper 4 (Higher)
A comparative measure calculated as when every experiment reaches the same fixed endpoint.
A value calculated as 1 divided by the time taken to reach the same endpoint in each trial; it is proportional to the reaction rate.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A value used to compare how fast reactions reach the same fixed endpoint; when the amount of change is held constant, it can be represented by 1 ÷ time.
For a fixed endpoint, a shorter reaction time means a faster reaction. Compare , not the times themselves, when numerical relative rates are required.
For experiments timed to the same endpoint, compare relative rate using . Remember that the rate ratio is the inverse of the time ratio.
Create a free account to read GCSE Chemistry revision notes for your exam board and track your progress.