Lecture 5- Thermodynamics

Question 1

First law of thermodynamics

Answer 1

Energy cannot be created or destroyed; it can can only be transformed.

Question 2

Second law of thermodynamics

Answer 2

The disorder/entropy of the universe is always increasing.

Question 3

Third law of thermodynamics

Answer 3

As temperature of a perfect crystalline solid approaches zero Kelvin, disorder/entropy approaches zero.

Question 4

Non-state function–define and list an example

Answer 4

Depends on the pathway of the function–e.g. heat, work

Question 5

State function–define and list an example

Answer 5

Independent of pathway–e.g. energy released

Question 6

Equation for change in energy

Answer 6

deltaE = q + w

where q = heat, w = work

Question 7

Enthalpy

Answer 7

Measure of a system’s internal energy

Question 8

Equation for enthalpy

Answer 8

H = E +PV
or
In biological systems, where PV doesn’t really change…
deltaH = deltaE

Question 9

How can you determine if a reaction is exothermic/endothermic based on enthalpy?

Answer 9

deltaH < 0 = exothermic

deltaH > 0 = endothermic