L5 & L6: Thermodynamics

Question 1

What is thermodynamics?

Answer 1

The science of energy transfer
- whether ac reaction or process will take place (not how fast)

Question 2

What is energy?

Answer 2

The ability to perform work

Question 3

What is kinetics?

Answer 3

The study of rates associated with a reaction or process

Question 4

What is kinetic energy?

Answer 4

The energy of moving objects or mass

Question 5

What is potential energy?

Answer 5

Energy that is stored

Question 6

What is heat?

Answer 6

• Energy caused by molecular motion
• thermal energy transfer between objects

Question 7

What is temperature?

Answer 7

The propensity for heat to flow from one body to another

Question 8

What is the equation for fahrenheit to celsius?

Answer 8

C = (F - 32) / 1.8

Question 9

What is work? and what is it determined by?

Answer 9

The transfer of energy in an ordered fashion

• defined by energy barrier it overcomes

(J)

Question 10

What is U, W and Q?

Answer 10

U - total internal energy of system
W - work
Q - heat

Question 11

What type of systems are there?

Answer 11

• isolated
• closed
• open

Question 12

What is an isolated system?

Answer 12

There is no exchange in matter and energy

Question 13

What is a closed system?

Answer 13

No wxchange in matter, but there is exchange in energy

Question 14

What is an open system?

Answer 14

There is exchange in matter and energy

Question 15

What are the signs for work done?

Answer 15

+W: work done ON system
-W: work donw BY system

Question 16

What are the signs for heat?

Answer 16

+Q: Heat ADDED TO system
-Q: Heat REJECTED BY system

Question 17

What is the 1st law of thermodynamics?

Answer 17

Algebraic sum of all energy changes in an isolated system is zero

= energy cannot be created or destryoes but merely trasnferred

Question 18

What are the 7 main forms of energy?

Answer 18

• electrical
• gravitational
• chemical
• radiation
• thermal
• mechanical
• nuclear

Question 19

What is enthalpy?

Answer 19

The heat energy change within a system is expressed as enthalpy
- expressed as a change value

Question 20

What are the signs for enthalpy?

Answer 20

+ve : endothermic = broken bonds = energy absorbed from the surroundings

-ve : exothermic = bond made = energy lost to the surroundings

Question 21

What are the 3 main types of enthalpy

Answer 21

Hc : crystallisation, liquid state to the solid state
Hf : melting, f stands for fusion
Hv: evaporation of a volatile solvent, v stands for vaporisation

Question 22

What is the 2nd law of thermodynamics?

Answer 22

The entropy of an isolated systen will either increase or stay the same but may not decrease

Question 23

What is entropy?

Answer 23

A measure of disorder (and probability)

Question 24

When does entropy increase?

Answer 24

Entropy increases when disorder increases

Question 25

What are the two ways of looking at entropy?

Answer 25

• probability
• molecular motion

Question 26

How does probability affect entropy?

Answer 26

The more random/disordered an event is, the more likely it is to occur

Question 27

How does molecular motion affect entropy?

Answer 27

The greater the range of the possible motions (degrees of freedom), the greater the entropy

• these motions are almost always present and increase with increased temperature

Question 28

What is heat capacity?

Answer 28

Amount of heat to be supplied to an object to produce a unit charge in its temperature

(J/K)

Reflect the ability to store heat energy

Question 29

What material have a higher heat capacity and why?

Answer 29

• material with a higher range of molecular mobilities (degrees of freedom) can store more energy
  = have a higher entropy

Question 30

What is the 3rd law of thermodynamics?

Answer 30

At absolute zero, the entropy of a perfectly crystalline substance is zero
= perfectly ordered

Question 31

Will a reaction take place spontaneously?

Answer 31

Lies in the balance between the enthalpy and entropy?

Question 32

What is the GFE equation?

Answer 32

Delta G = Delta H - T delta S

G - gibbs free energy
H - enthalpy
T - temperature
S - entropy

Question 33

What is GFE?

Answer 33

Gibbs free energy
The energy availability to perform work

Question 34

What are the signs for GFE?

Answer 34

+ve : system can perform work on the surroundings and the reaction will be spontaneous

-ve: system is not able to perform work on its surroundings and the reaction will not be spontaneous

Question 35

What is a spontaneous reaction is favoured by?

Answer 35

• -ve delta H (heat given out)
• +ve delta S (system becoming more disordered)

Question 36

What are the main parameters in the drug discovery process?

Answer 36

• solubility
• melting point
• partitioning

Question 37

What is solubility?

Answer 37

The max eq conc og a drig in a given solvent (saturation)

Question 38

What is melting point?

Answer 38

The transition from the crystalline to the liquid state (indicative of the bond strength)

Question 39

What is partitioning?

Answer 39

The distribution of a drug between oil and aq phases (indicative of permeation across biological membranes)

Question 40

How does thermodynamics help in drug receptor interactions?

Answer 40

Provides insights into
- bond strengths
- free energy of interactions
- molecular modelling
- longevity of drug-receptor interactions