The Rate Equation Flashcards
What does the rate equation tell us?
How rate is affected by the concentration of reactants and their order
Rate equation expression
Rate = k x [concentration of reactant]^order x [concentration of other reactant]^order
0 order reactants in the rate equation
Left out because if you put something to the power of 0 it = 1
1 order in rate equation
Simplified to just [reactant]
Because to the power of 1 is not needed to be expressed
Are catalysts included in rate equation?
Yes such as H+ ions if the reaction must take place in acidic conditions
Are spectator ions included?
NO
Bigger rate constant means…
Larger rate of reaction so the rate occurs at a faster rate
Why is it important to include orders?
Because it shows how rate is affected by the concentrations of these reactants and to what extent
How does the rate constant change?
The rate constant will stay the same for a certain reaction at a particular temperature
So temperature is the only variable that can change the value of K
Why does the value of k increases of temperature increases?
Because the rate of reaction increases (due to particles colliding more, more Ek so more collisions are of successful energy)
But conc doesn’t so to counteract increase in rate, value of k must increase
Find rate of reaction from rate of equation
Value of k x conc of reactant(^ of order) x conc of reactant(^ of order)
Find rate constant (k) from rate equation
Divide rate of reaction by the square brackets
Units of k
Rate of reaction units (eg moldm-3 s-1)
Divided by
Units of all concentrations, cancel out
(Powers are added together)
Inverse units to bring them to the top
Effect of concentration and time on value of k
k is independent of concentration and time
