physical chemistry (Fabio)

Question 1

define molecularity

Answer 1

The molecularity of an elementary reaction is the number of molecules involved in the collision.

Question 2

what is a unimolecular reaction and give an example

Answer 2

unimolecular reaction, a single molecule is involved
– e.g., radioactive decay, cis-trans isomerisations

Question 3

what is a bimolecular reaction

Answer 3

bimolecular reaction, the all-important collision
involves two distinct molecules colliding.
These molecules might be of identical
chemical composition or different.

Question 4

what value can molecularity not be

Answer 4

• can not be zero, fractional, infinite or imaginary
• can not be greater than three because there is not enough space

Question 5

what is the rate equation for a first order reaction in respect to A

Answer 5

v=k[A]

Question 6

what is the rate equation for a first order reaction in A and a first order reaction in B

Answer 6

v=k[A][B]

Question 7

what is the rate equation for a second order reaction with respect to A

Answer 7

v=k[A]^2

Question 8

for a zero order reaction what is the rate of reaction

Answer 8

the rates of zero order reactions do not vary with increasing or decreasing reactant concentrations. this means the reaction rate is equal to the rate constant k of that reaction

Question 9

what are the units for a zero order reaction

Answer 9

Ms-1

Question 10

for a first order reaction what is the rate of reaction

Answer 10

the rate of reaction increases linearly with increasing concentration of reactant

Question 11

what are the units for a first order reaction

Answer 11

s-1

Question 12

for a second order reaction what is the rate of reaction

Answer 12

normally dependent on temperature and relative concentration

Question 13

what are the units for a second order reaction

Answer 13

M-1s-1

Question 14

what is the half life equation for a zero order reaction and what does it depend on

Answer 14

t1/2 = [A]0/2k
depends on initial conc

Question 15

what is the half life equation for a first order reaction and what does it depend on

Answer 15

t1/2 = 0.693/k
the half life is independent on the inital concentration

Question 16

what is the half life equation for a second order reaction and what does it depend on

Answer 16

t1/2 = 1/k[A]0
half life depends on the inverse of inital conc

Question 17

what is the arrhenius equation

Answer 17

k=Ae^-Ea/RT
k the observed rate constant
A is the pre exponential factor
Ea is activation energy
R is the universal contant
T absolute temperature

Question 18

what is the equation for the rate of a chemical equation

Answer 18

rate of chemical reaction = number of collisons per secondfraction of collisions with proper orientationfraction of collisions with sufficient energy

Question 19

What is the pre exponential factor A

Answer 19

number of collisions per second*fraction of collisions with proper orientation

Question 20

what is the equation when comparing rates of reaction measured at any two temperatures

Answer 20

lnK1/K2=Ea/R(1/T2-1/T1)

Question 21

what is transition state theory

Answer 21

It is based on the idea that a molecular collision that leads to reaction must pass through an intermediate state known as the transition state

Question 22

what is the rate of reaction of transition state theory

Answer 22

rate = transition state concentration*decomposition frequency

Question 23

what can transition state concetration be written as

Answer 23

e^-deltaG/RT

Question 24

what can decomposition frequency be written as

Answer 24

v = KbT/h

Question 25

what is Michaelis-menten rate law

Answer 25

The Michaelis-Menten rate law describes the rate of enzymatic reactions. Enzymes are biological catalysts that accelerate chemical reactions in living organisms. The Michaelis-Menten rate law specifically describes the rate of an enzymatic reaction involving a substrate (S) binding to an enzyme (E) to form an enzyme-substrate complex (ES), which then converts to the product (P) and releases the enzyme

Question 26

what is the equation for the Michaelis - menten rate law

Answer 26

v=Vmax[S]/Km+[S]
V is the reaction rate or velocity.
Vmax is the maximum reaction rate, which occurs when the enzyme is fully saturated with substrate.
[S]is the concentration of the substrate.
Km ​is the Michaelis constant, which is a measure of the affinity of the enzyme for its substrate. It represents the substrate concentration at which the reaction rate is half of Vmax

Question 27

what does the michaelis-menten equation show

Answer 27

The Michaelis-Menten equation shows that the reaction rate increases as the substrate concentration increases. However, at high substrate concentrations, the rate approaches Vmaxindicating that the enzyme is saturated with substrate.

Question 28

what is a chain reaction

Answer 28

some reactions involve multiple intermediates which are produced and consumes through several steps, these are called chain reactions and the intermeidates are known as chain carriers.

Question 29

what is a consecutive reaction

Answer 29

reactions where the reactant forms an intermediate species which subsequently reacts to form the product, catalysts generally react with one or more reactants to form intermediated that subsequently give the final reaction product in the process regenerating the catalyst