Chapter 4 Flashcards
(91 cards)
How is energy measured?
As Joules or Calories
What are the two types of energy?
1) Potential Energy - stored energy
2) Kinetic Energy - energy of motion
Define Kinetic Energy
Includes Heat Energy which is the movement of atoms;
and Light Energy which is the movement of photons
Define Potential Energy
Includes Chemical Energy which is the energy stored in chemical bonds
What is the first law of Thermodynamics?
Energy cannot be created or destroyed, only converted from one form to another or transferred from one object to another
What type of energy is used with a dam?
Potential energy - the higher the water level (with the dam closed), the more potential energy
Kinetic energy- when the water is released
What is the 2nd law of Thermodynamics?
Energy conversions are not perfect and are accompanied by increased Entropy
*All systems tend toward disorder*
- The loss of Energy to Entropy is often observed as heat
Define Entropy
The Energy that is lost from the system, and cannot be used for further work
*It is the amount of disordeer in a system*
_____ are much more random than ______
Products are much more random than reactants
How does our biological metabolism lose energy as entropy?
By giving off heat as we exercise
Also as we metabolize ______ or ______ we convert a single molecule into several molecules of ______ and _____
Also as we metabolize glucose or sucrose we convert a single molecule into several molecules of CO2 and H2O
Summary of the 1st law of Thermodynamics
Energy before ——> Energy after
(Reaction)
Summary of the 2nd law of Thermodynamics
Energy before ——-> 3/4 usable energy + 1/4 Unusable
(reaction)
Chemical reactions _______________
Chemical bonds are __________
Chemical reactions release or store energy
Chemical Bonds are Potential Energy
Some Energy is always lost as _______
Entropy
Reactants are converted to Products
C6H12O6 + 6O2 ——–> 6H2O +6CO2
how many molecules in each?
C6H12O6 + 6O2 = 7 molecules
6H2O + 6CO2 = 12 molecules
Define Exergonic
Example?
Net release of energy
The reactants contain more energy than the products
-(delta)G
EX. fire
Define Endergonic
Example?
Net storage of energy
The products contain more energy than the reactants
+(delta)G
EX. Photosynthesis
What is the formula for Gibb’s free Energy?
What do each stand for?
(delta) G= (delta)H- T(delta)S
(delta) H = change in enthalpy or heat (potential Energy)
(delta) S = change in entropy
T= temperature
What is the differene between enthalpy and entropy?
Enthalpy = the transfer of energy
Entropy = disorder = energy lost
What does gibb’s free energy allow?
Gibb’s free energy allows you to determine whether a reaction will be spontaneous, and under what conditions
So both change in ________ and change in ________ dictate whether a reaction is favourable or not
So both change in potential energy ((delta)H) and change in entropy ((delta)G) dictate whether a reaction is favourable or not
A glass of ice melts at room temperature
Ice ———-> water
Is H higher for ice or water?
Is S higher for ice or water?
H is higher for water
S is ********
Ice ——> water
(delta) H =
(delta) S =
So as long as _______ the reaction will be favoured
(delta) H is positive- it is an endothermic reation
(delta) S is negative
So as long as T(delta)S>(delta)H the reaction will be favoured