thermodynamics and kinetics

Question 1

kinetics

Answer 1

rate of reaction depends on the pathway from reactants to products

Question 2

thermodynamics

Answer 2

tells us whether a reaction is spontaneous based only on the properties of reactants and products

Question 3

exergonic reaction

Answer 3

ΔG< 0
reaction is spontaneous

Question 4

endergonic reaction

Answer 4

ΔG> 0
the reaction is not spontaneous

Question 5

endergonic reaction in biochemistry

Answer 5

they will be coupled with exergonic reactions that will give them the energy to occur

Question 6

1st law of thermodynamics

Answer 6

ΔE = q + w

ΔE = change in internal energy
q= heat transferred
w= work done

Question 7

the internal energy of a system

Answer 7

U= potential + kinetic energye

Question 8

exothermic reaction

Answer 8

there is a reduction of the potential energy: the new bonds formed have less potential energy than the ones of the reactants. New bonds that are formed are stronger than one of the reactants

Question 9

enthalpy of a reaction

Answer 9

change in the
potential energy

Question 10

what happens in spontaneous processes

Answer 10

we have an increase of disorder

Question 11

entropy

Answer 11

a thermodynamic function that increases with the number of energetically equivalent ways to arrange the components of a system

Question 12

the greatest number of microstates

Answer 12

highest entropy

Question 13

2nd law of thermodynamics

Answer 13

the total entropy of an isolated system can never decrease over time.

Question 14

Gibbs free energy

Answer 14

G= ΔH - TΔS

Question 15

positive ΔG

Answer 15

reaction is non-spontaneous

Question 16

negative ΔG

Answer 16

reaction is spontaneous

Question 17

rate equation

Answer 17

rate = change in concentration of reactants or products/ time

Question 18

factors that affect the rate of a reaction

Answer 18

1. nature of the reactants
2. conc of the reactants
3. temperature
4. presence of catalysts

Question 19

why can Ca react more vigorously than Mg

Answer 19

this is bc the ionisation energy decreases down in the group so the reactivity increases as you go down

Question 20

reaction rate equation

Answer 20

V = k [A]a [B]b [C]γ

k: reaction constant-> temp dependent
v: reaction rate
not a, b, γ not stoichiometric coefficients

Question 21

rate-determining step

Answer 21

slowest step

Question 22

2-step mechanism

Answer 22

1st step has a higher activation energy than the second step. so the 1st step is much slower than the 2nd step and so the 1st step determines the overall rate of reaction

Question 23

activation energy

Answer 23

energy that must be provided to compounds to result in a chemical reaction. it is energy that is required to reach the activated complex

Question 24

how do we get from the reactant to the product

Answer 24

the molecule must go through a high-energy state called the activated complex/ transition state

Question 25

arrhenius equation:

Answer 25

k= Ae ^-Ea/RT A= frequency factor Ea= activation energy

Question 26

Boltzmann maxwell distribution

Answer 26

the higher the temp, the wider the energy distribution and the greater the average energy. The proportion of molecules that have an energy equal to or greater than the Ea is greater and therefore they are more likely to react

Question 27

catalysts

Answer 27

a substance that increases the rate of a chemical reaction but is not consumed by a reaction. catalysts work by providing an alternative pathway for the reaction one in which the RDS has a lower Ea

Question 28

effect of catalysts on the position of the equilibrium

Answer 28

does not affect it