A2: Rates of Reactions Flashcards
State the effect, if any, on the value of the rate constant k when the temperature is
LOWERED but all other conditions are kept constant
1) LOWERS
2) fewer particles have sufficient (ACTIVATION) energy (to REACT)
How to deduce which is the rate-determining step?
same amounts (of REACTANTS) as in RATE EQUATION
Define “Reaction Rate”
it’s the CHANGE IN THE AMOUNT of reactants/products PER UNIT TIME.
If the REACTANTS are in SOLUTION, the rate will be CHANGE IN CONC. PER SECOND
If the gradient is ZERO, what has happened to the reaction?
It has FINISHED
What are the units of “Rate”? All first orders
moldm-3s-1 BOTH MINUSES
the bigger the value of “K” is…the ______ the reaction
FASTER
what does “K” represent?
the rate KONSTANT
Why does the RATE OF REACTION
INCREASE
when you INCREASE the TEMPERATURE?
cos you’re increasing the NO. OF COLLISIONS between REACTANT MOLECULES and also, the ENERGY of EACH COLLISION.
But, the conc. of reactants and orders of reactants stay the same SO value of K must INC. for the RATE EQUATION TO BALANCE
Write the general Rate Equation:
Rate = K [A]m [B]n
How do you calculate the GRADIENT of the tangent on a graph?
Y DIVIDED BY X
your (ex) is lame so right at the back
What is the “RATE DETERMINING STEP” ???
the SLOWEST step in a Multi-Step reaction
What do the ORDER OF REACTIONS show you?
orders…with respect to a reactant shows the NUMBER OF MOLECULES of that REACTANT that are involved in the RATE-DETERMINING STEP
The pH scale is a measure of?
Hydrogen ion concentration
Explain the effect of an INCREASE in TOTAL PRESSURE on the RATE of attainment of equilibrium:
- Increase
- More particles in a given space
- Higher chance of more successful collisions
