Rates of reaction/Chemical kinetics/Rate laws Flashcards
What is thermodynamics about?
A reaction’s energy requirement. Tells us whether a reaction is reactant-favored or product-favored.
What is kinetics about?
How fast a reaction goes from reactants to products. It is about reaction mechanisms and reaction rates.
True or False: All reactions are kinetically favored.
False. Reactions can be kinetically or thermodynamically favored.
Which type of reaction form quickest, kinetically or thermodynamically?
Kinetically.
What is chemical kinetics?
The study of the factors that affect reaction rates and the mechanism by which reactions proceed.
What is reaction rate?
The speed/rate of a chemical reaction or quantity change over a period of time.
When calculating the reaction rate, what is placed in front of the reactants?
A negative sign.
When calculating the reaction rate, what is placed in front of the products?
A positive sign.
What is instantaneous rate?
The change in the reaction rate at any ONE particular time. Calculated by measuring the slope of the tangent line to the curve.
What is average rate?
The change in the reaction rate measured over a particular time period. Calculated by measuring the linear approximation of the curve.
*The larger the time period, the more it deviates from the instantaneous rate.
What occurs as concentration increases?
The # of collisions increases.
What occurs as volume increases?
The # of collisions decreases.
What is the reaction speed of smaller molecules/ions?
Fast.
List the three states of matter in order from fastest moving molecules to slowest moving molecules.
Gas, Liquid, Solid.
Why do ions react quickly?
There are no bonds that need to be broken.
What happens to the speed of the reaction as temperature increases?
The speed increases.
What do catalysts do to a reaction?
Speed it up or slow it down.
How do catalysts speed up a reaction?
They lower the activation energy.
*Are not consumed during the reaction.
What is the rate of reaction proportional to?
The concentration of reactant A.
What is the rate of reaction equation?
(M/s)=k[A]^n.
M/s= Molarity/Second
k= rate constant at temp.
n= reaction order for reactant A*.
*Not always the case.
What is the rate law?
Rate= k[A]^x[B]^y.
x and y=reaction order for the reactants.
How is reaction order determined?
Experimentally.
What does the sum of the reaction orders equal?
The overall order of the reaction.
What happens if doubling a reactant’s concentration corresponds to no change?
Zero order.
What happens if doubling a reactant’s concentration corresponds to a doubling in the reaction’s rate?
First order.
What happens if doubling a reactant’s concentration corresponds to a quadrupling of the reaction’s rate?
Second order.
