r2.2 rate of chemical change Flashcards
(7 cards)
1
Q
what is rate of reaction?
A
rate of reaction is defined as the change in concentration of reactants or products per unit time (units mol dm⁻³ s⁻¹)
2
Q
what is average rate of reaction?
A
the average rate of reaction is the mean reaction rate over a period of time
3
Q
what is instantaneous rate of reaction?
A
the instantaneous rate of reaction is the reaction rate at a given moment in time
4
Q
how do you calculate rate of reaction using reactants?
A
RoR = decrease in reactant conc / change in time
5
Q
how does amount of reactant in a reaction change over time?
A
- at the start of the reaction, each reactant has its greatest concentration
- the RoR decreases with time as the conc of reactant particles decreases which results in a lower frequency of collisions between the reactant particles
- this can be seen in a graph, where the line is initially steep but eventually plateaus when the limiting reactant is consumed
6
Q
how do you calculate rate of reaction using products?
A
RoR = increase in product concentration / change in time
7
Q
how can you determine the instantaneous rate of reaction from a graph?
A
- draw a tangent to the curve at a specific time
- measure the gradient of the line
- gradient of the line = rate of reaction
