predicting pharmaceutical stability

Question 1

what is thermodynamics

Answer 1

general description of energy and its transfer

Question 2

what does thermodynamics allow us to predict

Answer 2

whether a reaction will occur or not and what physical instabilities will occur like polymorphism and phase changes

Question 3

in short, explain what each law of thermodynamics is

Answer 3

zeroth- concept of temperature
first- conservation of energy
second- entropy principle
third- absolute zero temperature

Question 4

what has energy

Answer 4

any mass in any form of motion has energy

Question 5

what is energy measured in

Answer 5

joules

Question 6

what is an open system

Answer 6

both matter and energy can cross the boundary between system and its surroundings

Question 7

what is a closed system

Answer 7

no matter can transfer through

Question 8

what is an isolated system

Answer 8

no matter or energy transfer

Question 9

what is a system

Answer 9

part of universe chosen in consideration

Question 10

what is zeroth law

Answer 10

if A and B are in thermal equilibrium and so are B and C, then TA=TC

Question 11

what is work

Answer 11

transfer of energy from one system to another by a force moving its point of application in its own direction

Question 12

what symbol represents work

Answer 12

w

Question 13

what is the change in energy in work associated with

Answer 13

ordered or coordinated movement of particles in 1 or more directions in the surrounding

Question 14

what symbol represents heat

Answer 14

q

Question 15

what is heat

Answer 15

transfer of energy due to differences in temperature

-involves trans/rotational motion and inter/intramolecular vibrations

Question 16

what is the exchange in energy from heat associated with

Answer 16

disorder/chaotic movements of atoms

Question 17

example of heat

Answer 17

ice melting

Question 18

example of work

Answer 18

movement of piston due to expansion/compression of a gas

Question 19

what is heat and work

Answer 19

energy in the process of being transferred

Question 20

what does +ve and -ve heat mean

Answer 20

+ve=energy absorbed
-ve=energy given out

Question 21

what does +ve and -ve work mean

Answer 21

+ve=work done on system, compression
-ve=work done by system, expansion

Question 22

what is internal energy (u)

Answer 22

total energy in system

Question 23

what is first law of thermodynamics

Answer 23

theres a change in internal energy when a system changes from an initial state with Ui to a final state with Uf
∆U=Uf-Ui

Question 24

equation for first law of thermodynamics

Answer 24

∆U=q+w

Question 25

equation for the enthalpy of an open system

Answer 25

∆H=∆U+P∆V

Question 26

what is thermochemistry

Answer 26

study of heat changes with chemical reactions

Question 27

what are the standard conditions

Answer 27

pure unmixed substance, 25 degrees celcius, 1 atm

Question 28

what is standard enthalpy/∆H

Answer 28

enthalpy change when reactants in their standard states are converted into products in their standard states

Question 29

what is hess’s law

Answer 29

enthalpy change is independent o the route taken

Question 30

what is entropy

Answer 30

disorder of a system
(liquid to solid=more order=less entropy)

Question 31

what is second law of thermodynamics

Answer 31

in isolated systems entropy increases by a spontaneous process

Question 32

equation in second law of thermodynamics

Answer 32

∆S=q/T

Question 33

are spontaneous processes reversible and what happens to the entropy

Answer 33

spontaneous processes are irreversible, entropy increases
reversible processes are in equilibrium and entropy remains unchanged

Question 34

what is q(surr)

Answer 34

heat transferred to surroundings
∆S(surr) is proportional to ∆q(surr)

Question 35

heat has more impact when transferred to a cold reservoir, what is the equation that shows this

Answer 35

∆S(surr) is proportional to 1/T(surr)

Question 36

what is the third law of thermodynamics

Answer 36

entropy of a perfectly crystalline material is zero at T=0k

-at )k thermal motion is eliminated and there is no disorder

Question 37

what are the causes of spontaneous change

Answer 37

1. energy difference between initial and final states
2. entropy difference between initial and final states

Question 38

gibbs free energy equation

Answer 38

∆G=∆H-T∆S

Question 39

what do values of ∆G mean

Answer 39

∆G<0 spontaneous
∆G=0 equilibrium
∆G>0 not spontaneous

Question 40

what is ∆G in terms of work done

Answer 40

maximum non expansion work done at a constant pressure

Question 41

describe the graphs of ∆G

Answer 41

∆G decreases= reaction goes to completion
∆G decreases then increases= equilibrium
∆G increases= reaction doesnt occur

Question 42

equilibrium constant equation

Answer 42

Keq=[products]/[reactants]

Question 43

what do the values of the equilibrium constant (K) mean

Answer 43

K»1 products dominate the reaction mixture
K«1 reactants dominant
K=1 reactants and products and in similar abundance

Question 44

equation with ∆G and equilibrium constant

Answer 44

∆G=-RTlnK