UPH012: Biophysics and Biomaterials

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Questions and Answers

What aspect of a system does thermodynamics primarily deal with?

The behavior of individual particles

Chemical reactions at varying temperatures

The stability of the entire system (correct)

Interactions at the atomic level

Which type of thermodynamic system can exchange both matter and energy with its surroundings?

Equilibrium system

Closed system

Isolated system

Open system (correct)

Which statement accurately describes the relationship between thermodynamics and kinetics?

Thermodynamics tells us what should happen, while kinetics addresses whether it will happen. (correct)

Kinetics is solely focused on the temperature of a system.

Thermodynamics explains how fast a process occurs.

Kinetics deals with the stability of systems.

At what condition is ice more stable than water?

-5°C at 1 atm pressure Signup and view all the answers

What does the Kirkendall effect describe?

Diffusion of atoms in different phases Signup and view all the answers

How is biological thermodynamics characterized compared to other systems?

Biological systems are open systems Signup and view all the answers

Which of the following quantities is not typically addressed by thermodynamics?

Specific time for water to freeze Signup and view all the answers

What is generally true about entropy in thermodynamics?

It has a statistical nature and relates to randomness Signup and view all the answers

What is the main concept of the First Law of Thermodynamics?

The total energy of the universe is constant. Signup and view all the answers

How is internal energy denoted in thermodynamics?

U Signup and view all the answers

Which of the following statements about internal energy is correct?

It includes all types of molecular motion. Signup and view all the answers

What does the equation ΔU = w + q represent?

The change in internal energy of a system. Signup and view all the answers

What is true about heat (q) and work (w) compared to internal energy (U)?

They are represented by lowercase letters. Signup and view all the answers

Which of the following correctly describes the concept of internal energy?

It is the total energy associated with molecular movement and arrangement. Signup and view all the answers

In a complete thermodynamic cycle, what is the value of ΔU?

0 Signup and view all the answers

What distinguishes work (w) from heat (q) in a thermodynamic context?

Work is non-random movement of particles, heat is random movement. Signup and view all the answers

What does a negative Gibbs free energy change (ΔG) indicate about a reaction?

The reaction will occur spontaneously. Signup and view all the answers

What happens to ΔG when a system is at equilibrium?

ΔG equals zero. Signup and view all the answers

Which equation correctly represents the relationship of Gibbs free energy change at constant temperature?

ΔG = ΔH - TΔS Signup and view all the answers

What is the primary effect of increasing temperature on the Gibbs free energy change (ΔG)?

It can either increase or decrease ΔG depending on entropy change. Signup and view all the answers

In the context of thermodynamics, what does the term 'work' refer to?

The energy transfer that results in physical motion. Signup and view all the answers

What signifies a reaction having a favorable forward reaction in terms of Gibbs free energy?

ΔG is less than zero. Signup and view all the answers

What does the equation ΔG = H - TS represent in thermodynamics?

The balance between enthalpy, temperature, and entropy. Signup and view all the answers

What does the sign convention for heat transferred to the surroundings indicate?

q < 0 Signup and view all the answers

Study Notes

Thermodynamics Overview

Thermodynamics is crucial for engineers and scientists, encompassing system-level analyses rather than interactions at the microscopic level.
Relevant quantities include temperature (T) and pressure (P), which are averaged over large collections of molecules or atoms.
Questions about the properties of individual atoms, such as their entropy, fall outside thermodynamics' scope.

System and Surrounding

Thermodynamics focuses on system stability, describing what should happen, not what will happen (kinetics addresses the latter).
Example: At -5°C, ice is more stable than water; cooling water to -5°C raises questions about freezing and duration—these are not addressed by thermodynamics.
The universe comprises a system and its surrounding environment.

Types of Systems

Systems can be classified as closed, open, or isolated.
In biological contexts, systems are typically open, allowing for exchange with their environment.

Biological Thermodynamics

Energy is difficult to define, but it is often described as the capacity to produce an effect.
The First Law of Thermodynamics states that the total energy in the universe is constant; energy can change forms but is neither created nor destroyed.

Internal Energy

Internal energy (U) of a system is the total kinetic and potential energy related to the motion and configuration of its molecules.
U is a state function: its value depends only on the current state, not on how that state was reached.

Work and Heat

Relationship: ΔU = w + q, where U is internal energy, w is work, and q is heat.
Heat (q) and work (w) are not state functions, as they depend on the path taken during a process.
Heat involves random particle movement, while work involves organized particle movement.

Sign Conventions

Heat is considered positive (q > 0) when transferred into the system and negative (q < 0) when transferred to the surroundings.

Gibbs Free Energy (G)

Gibbs free energy combines concepts from the First and Second Laws: G = H - TS, where H is enthalpy and S is entropy.
Change in Gibbs free energy can be calculated as ΔG = ΔH - TΔS at constant temperature.
In reversible systems, ΔG = 0 indicates equilibrium; negative ΔG signifies spontaneous processes.
The magnitude of ΔG indicates the driving force for a reaction but does not predict the reaction time.

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Description

This quiz explores key concepts in biophysics and biomaterials, focusing on thermodynamics and diffusion kinetics. It covers topics such as free energy, internal energy, equilibrium, stability, and the statistical nature of entropy. Prepare to test your understanding of these fundamental principles.