🏷️ LIMITED TIME OFFER: GET 20% OFF GRADE+ YEARLY SUBSCRIPTION →
Log in
HomeClass Notes1,200,000AU40,000

CH1001 Lecture Notes - Lecture 10: Chemical Thermodynamics, Vacuum Flask, Internal Energy

94 views18 pages
coffeebear832
16 Jul 2018
School
James Cook University
Department
CH
Course
CH1001
Professor
Mark Barnes

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Thermodynamics is the study of energy and how it is transferred in physical and chemical processes. Thermodynamics looks at the exchange of energy between a chemical system and the surrounding environment. Chemical thermodynamics describes whether or not a process will occur spontaneously, and also the extent to which a reaction goes to completion. The over-riding phenomenon in determining these is the free (or available) energy in the system, which is dependent on enthalpy (heat) and entropy (disorder). The sum of all nuclear, translational, rotational, vibrational, electronic and interaction energies in the system. A function of the heat absorbed or released by a chemical system. Measured by a change of temperature at constant pressure. A measure of the number of ways in which energy can be distributed in a system. A system consists of one or more chemical processes. The surroundings consist everything else in the universe except the system. Can gain or release energy across a boundary but not mass.

Get access

Grade+20% off
$8 USD/m$10 USD/m
Billed $96 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers
Class+
$8 USD/m
Billed $96 USD annually
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
30 Verified Answers

Related Documents

CHMA11H3 Lecture Notes - Lecture 22: Spontaneous Process, Enthalpy, Thermodynamics
erinsea-lion742
CHEM10006 Lecture Notes - Lecture 1: Thermodynamics, Gibbs Free Energy, Enthalpy
roseturtle504
Biochemistry 3381A Chapter Notes - Chapter 3: Gibbs Free Energy, Thermodynamic Potential, Equilibrium Constant
jadefrog467

Related Questions

1.) Which statement isincorrect?

(a) Energy is the capacity todo work or to transfer heat.

(b) Kinetic energy is theenergy of motion.

(c) Potential energy is the energy that a system possesses by virtue ofits position or composition.

(d) A process that absorbsenergy from its surroundings is called exothermic.

(e) The Law of Conservation of Energy is another statement of the FirstLaw of Thermodynamics.

2. Which of the following statementsabout the first law of thermodynamics and energy is false?

(a)Kinetic energy cannot be convertedto potential energy.

(b)Kinetic energy =1/2mv2.

(c)All the energy in the universe isconserved.

(d)A system can never decrease itsenergy.

(e)Potential energy is the energy ofposition or composition.

3. Whichone of the following thermodynamic quantities isnot a state function?

(a)work (b) enthalpy (c)entropy (d) internalenergy (e) free energy

My first answer was wrong. Can you explain answers?

As entropy increases there will be more useful energy to do‘work’. True or false?

False. As entropy increases, there will generally be less usefulenergy to do work. We can think of entropy as usually being presentin the form of heat energy. Imagine a car motor, which attempts toturn chemical potential energy into kinetic energy (movement). Lessefficient motors will get hotter for the same amount of fuelconsumed. When you drive a car you hope that most of the fuelenergy is converted into kinetic energy and not lost as heat(entropy). The hotter the car (and thus the more entropy) the lessefficient the ability to do ‘work’ (the moving of the vehicle).
True. As entropy increases, there will generally be more usefulenergy to do work. We can think of entropy as usually being presentin the form of heat energy. In most biological and mechanicalsystems it is heat energy which is captured to do useful 'work'.Heat energy, the random movement of molecules, and increases inentropy are central to doing useful work.

Biological systems sometimes appear on the surface to break theSecond Law of Thermodynamics – by seemingly increasing the order inthe overall system. They don’t. Why?

a. Earth (and living things on it) are not a closed system. Thesun's constant input of energy in the form of photons is harnessedby living things to create internal order within themselves. Butwithout such a constant input of energy, most biological systems onearth would break down.
b. The Second Law tells us that no natural process can occurunless it is also associated with an increase in the entropy of theuniverse. A living organism (such as an animal or plant) brings inmatter and energy from its environment and uses this to creategreater order within its body: the processes of life. But it isimportant to keep in mind that all animals and plants are also partof a larger system of the environment around them. While creating asmall ‘pocket’ of order, the processes of life (metabolism,movement, etc..) releases heat into the environment – thusincreasing the entropy of the universe and following the2nd law.
c. Living things, by harnessing energy to create order (withinand around themselves) actually create a paradox in questionssurrounding the first and second laws of thermodynamics andseemingly violate many previously held assumptions.
d. Both a and b above are correct.

When plants capture energy in the photons of sunlight andconvert that energy into the chemical bonds of organic molecules,are they creating new energy?

No, the energy is being transferred from one form into another.But no new energy is being created.
No, the overall total energy is decreasing over time.
Yes, by capturing photons, the plants are creating newenergy.
Yes, by capturing photons, the plants are creating new energy -of a different wavelength.