chapter 3 section 1

Question 1

What is water’s specific heat and why is it important?

Answer 1

4.184 J/g°C; it allows water to resist temperature changes, buffering environments and organisms.

Question 2

What is a system in thermodynamics?

Answer 2

The portion of the universe being studied (e.g., a cell, organism, or chemical mixture).

Question 3

What are the surroundings in thermodynamics?

Answer 3

Everything outside the system

Question 4

What are the three types of thermodynamic systems?

Answer 4

Isolated, closed, and open.

Question 5

What is an isolated system?

Answer 5

Cannot exchange matter or energy with surroundings

Question 6

What is a closed system?

Answer 6

Exchanges energy but not matter with surroundings.

Question 7

What is an open system?

Answer 7

Exchanges both matter and energy with surroundings.

Question 8

What kind of system are living organisms?

Answer 8

Open systems (exchange nutrients, wastes, and heat with surroundings).

Question 9

What does an isolated system exchange with surroundings?

Answer 9

Neither matter nor energy.

Question 10

What does a closed system exchange with surroundings

Answer 10

Energy, but not matter.

Question 11

What does an open system exchange with surroundings?

Answer 11

Both matter and energy.

Question 12

Which type of system best represents living organisms?

Answer 12

Open systems.

Question 13

What does enthalpy (H) represent?

Answer 13

Heat content of a system, based on bonds in reactants and products.

Question 14

What does a positive ΔH mean?

Answer 14

Heat absorbed by the system.

Question 15

What does a negative ΔH mean?

Answer 15

Heat released by the system to surroundings.

Question 16

What does entropy (S) measure?

Answer 16

Disorder or randomness; energy dispersion into microstates.

Question 17

What is Gibbs free energy (G)?

Answer 17

Energy available to do work:
G=H−TS.

Question 18

What does negative ΔG indicate?

Answer 18

Exergonic process (energy released to surroundings).

Question 19

What does positive ΔG indicate?

Answer 19

Endergonic process (energy absorbed from surroundings).

Question 20

Are H, S, and G state functions?

Answer 20

Yes, they depend only on the system’s state, not the path taken.

Question 21

How can absolute entropy be calculated?

Answer 21

S=KlnW

K=boltzman constant
W=amount of microstates

Question 22

in biology, which is more useful: absolute entropy or entropy change?

Answer 22

Entropy change.

Question 23

How can entropy change (ΔS) be calculated?

Answer 23

From enthalpy change (ΔH) and free energy change (ΔG).

Question 24

What does an increase in entropy indicate?

Answer 24

Greater disorder and less organization.

Question 25

What does a decrease in entropy indicate?

Answer 25

More order, organization, and higher information content.

Question 26

Who introduced the idea of negative entropy in biology?

Answer 26

Erwin Schrödinger in What Is Life? (1944)

Question 27

What term did Léon Brillouin later introduce?

Answer 27

“Negentropy.”

Question 28

How are living systems described in terms of entropy?

Answer 28

Highly organized, low-entropy systems maintained by constant energy input.

Question 29

What does the first law of thermodynamics state?

Answer 29

Energy is conserved; it cannot be created or destroyed, only converted or transferred.

Question 30

What are the consequences of the first law?

Answer 30

Total energy of the universe is constant. Energy can change form, do work, or transfer between system and surroundings.

Question 31

What does the second law of thermodynamics state about entropy?

Answer 31

Systems tend to move from ordered (low entropy) to disordered (high entropy) states.

Question 32

What do all natural processes tend toward?

Answer 32

Equilibrium—a state of minimum potential energy and maximum energy dispersal.

Question 33

What does the third law of thermodynamics state?

Answer 33

The entropy of a perfect crystal approaches zero as temperature approaches 0 K.

Question 34

How is absolute entropy calculated?

Answer 34

S=∫0^T​ CP​ d(lnT)

Question 35

What happens to ΔG at equilibrium?

Answer 35

ΔG = 0, and [c][D]/[A][B]=Keq ​ .

Question 36

What does ΔG° indicate about a reaction’s distance from equilibrium?

Answer 36

ΔG° ≈ 0 → reaction near equilibrium. Large |ΔG°| → reaction far from equilibrium.

Question 37

What does it mean when ΔG = 0?

Answer 37

The system is at equilibrium; no net forward or reverse reaction.

Question 38

What happens if ΔG < 0?

Answer 38

Reaction is exergonic, proceeds spontaneously in the forward direction.

Question 39

What happens if ΔG > 0?

Answer 39

Reaction is endergonic, spontaneous in the reverse direction.

Question 40

Does ΔG tell us how fast a reaction occurs?

Answer 40

No, ΔG only shows spontaneity (thermodynamic favorability), not reaction rate (kinetics).

Question 41

How are standard-state thermodynamic values denoted?

Answer 41

With a superscript degree (°), e.g., ΔH°, ΔS°, ΔG°.

Question 42

What does ΔG represent?

Answer 42

The free energy change under actual conditions (depends on concentrations, T, pH, etc.).

Question 43

What happens at equilibrium (ΔG)?

Answer 43

ΔG = 0.

Question 44

How are ΔG° and K_eq related?

Answer 44

ΔG° = –RT ln K_eq.