3.1 Energy and the laws of thermo Flashcards
Energy (2)
Capacity to do work or be transferred as heat
kinectic energy+ example
energy possessed by an object because it is in motion
waves in an ocean, falling rock, a kicked football
potential energy
stored energy
the energy an object has because of its position or chemical structure
the potential energy possessed by a specific molecule , its______ is the energy that is _______
chemical energy
stored in the bonds between the atoms that make up the molecule
further away from the nucleus the ____ potential energy an electron possesses
more
thermodynamics
the branch of science that concerns energy and how it changes during chemical and physical transformations
system
object being studied
isolated system+ex
one that does not exchange matter or energy with its surroundings.
The universe itself
closed system+ ex
can exchange energy but not matter with its surroundings
earth
open system+ex
both energy and matter can move freely between the system and the surroundings
ocean ( absorbs and release energy, and as a component of the hydrological cycle, water is constantly being lost and gained thru evaporation and precipitation)
first law of thermodynamics + example
energy can be transformed from one form to another or transferred from one place to another but it cannot be created or destroyed
Niagara Falls: Water at the top of the fall has high potential energy because of its location in earth’s gravitational field. As the water moves over the waterfall its potential energy is converted into kinetic energy. The higher the waterfall, the more kinetic energy the water will possess. When the water reaches the bottom of the waterfall, its kinetic energy is transformed into other types of energy: heat, sound and mechanical energy (causes weathering).
Second law of thermodynamics +examples
The entropy of a system and the surroundings will increase- energy and matter will always become more spread out
when you heat a pan on a stove and the switch the stove off. At first the heat energy is concentrated very close to the pan, but slowly the heat energy disperses throughout the kitchen. This energy dispersal continues until no part of the room contains more energy than any other.
Entropy (S) (3)
the tendency of energy to become dispersed or spread out
the measure of disorder or randomness in a system because energy becomes more dispersed as matter becomes more dispersed.
the measure of how much energy and matter has moved from being localized to becoming more widely dispersed.
enthalpy (delta h) (3)
the heat content of a system
the change in energy between bonds of product and reactants
in a molecule, enthalpy reflects the number and kinds of chemical bonds that exist between atoms
endothermic(3)+ex
overall change of enthalpy,
products what?
transformation that results in a system taking up heat from its surroundings
products having more thermal energy than the initial state of the system
overall change in enthalpy is positive
ex: melting of ice
exothermic(3)+ex
overall change of enthalpy,
products what?
a process that releases heat
since the product have less thermal energy than the starting molecules
delta H is neg
Ex: burning of wood
Heat and enthalpy relationship at constant temperature
The heat that is absorbed or released by a reaction at constant pressure is the same as the enthalpy change, and is given the symbol ΔH
how changes in both enthalpy and entropy influence the spontaneity of a reaction (2)
- reactions tend to be spontaneous if they are exothermic; that is if the products have less thermal energy than the reactants.
- reactions tend to be spontaneous when the entropy of the products is greater then the entropy of the reactions
tell me how breaking down of glucose in cellular respiration is spontaneous (2)
- exothermic: there is heat released was a result of bonds being broken and formed. The electrons are more strongly held in the product molecules than in the reactant molecules and the excess energy is released to the surroundings.
- Due to the entropy of the products being greater than the entropy of the reactants
whenever a chemical reaction results in an increase in the number of molecules, entropy
increase
entropy also increases when: (phase change+why) (3)
solid -> liquid
liquid -> gas
energy is being spread out more readily as matter undergo phase change
spontaneous process
a process that can occur without a constant input of energy
Gibb’s free energy (2)
-formula
the amount of energy available in a system to do work
delta g= delta H-T(delat S)
spontaneous reaction def with Gibbs (3)
the free energy go the product is less than the free energy of the reactions
delat G is negative
exergonic process
Tell me if spontaneous or not:
Delta H>0
Delta S>0
delta g= delta H-T(delat S)
spontaneous at high temps
Tell me if spontaneous or not:
Delta H>0
Delta S<0
delta g= delta H-T(delat S)
non spontaneous
Tell me if spontaneous or not:
Delta H<0
Delta S<0
delta g= delta H-T(delat S)
spontaneous at low temp
Tell me if spontaneous or not:
Delta H<0
Delta S>0
delta g= delta H-T(delat S)
spontaneous
exergonic process (2)
a spontaneous process
delta g is negative
endergonic process (2)
a non-spontaneous reaction
delta g is positive
it is the overall change in free energy of product compared to the reactants that determine whether or not a reaction _______, which is unrelated to the energy required for _____
is exergonic or endergonic,
activation
exergonic reactions move towards _____ but do not go to _______
equilibrium
completion
Why not to completion? (3)
The reaction does not stop but with the build up of the concentration of products, the reverse reaction keeps replacing the reactants as fast as they can produce product.
regardless of the amount of reactants and products in the initial mixture the system reached the same state in which the proportion off products to reactants was a constant.
delta G=0 no capacity to do work
metabolism
The collection of all the chemical reactions present within a cell or organism
many different metabolic reactions take place within a cell resulting in
the synthesis or breakdown of a huge variety of molecules
catabolic pathway (3)+ex
a series of chemical reactions that results in the breakdown of larger more complex molecules into smaller lesser complex ones
energy is released
free energy of final product is less then the free energy of starting molecules
Ex: cellular respiration. Energy rich molecules being converted to simpler lower energy molecules such as h2o and co2
anabolic pathway(2)+ex
a series of reactions that results in the synthesis of large more complex molecules from simpler starting molecules
require energy because the overall free energy of the products is greater than the free energy of the starting molecules
Ex: synthesis of specific carbs and proteins/ nucleic acid
photosynthesis
The energy acquired through______ is used to drive _______
catabolic processes
anabolic processes
the specific form of chemical energy that most often. links the two type of pathways is the molecule___
ATP
ATP-ADP vice versa equation
Explain why ATP generates and the process is used(2)
First of all energy is released when new bonds are formed and is needed to break bonds. The three phosphate groups at the tails are negatively repulsed so a relatively small amount go energy is required to break the bond. Compare that to a large amount of energy that is released when the more stable products ADP and Pi are formed.
Also spontaneous because of an increase in entropy as energy moves from being localized on one molecule to being spread out on two molecules.
energy coupling
an endergonic reaction occurs by being coupled to an exergonic reaction. For the majority go energy coupling reactions, the energy is provided by the exergonic breakdown of ATP.
energy coupling during metabolism requires an enzyme that binds to both a (3)
molecule of ATP and a molecule of substrate and facilitates the transfer of the terminal phosphate group from ATP to the substrate.
The addition of phosphate to the substrate increases its free energy and makes it more reactive allowing the second reaction to occur spontaneously.
An important aspect of energy coupling is that the inclusion of an enzyme facilitates the movement of potential energy from a molecule of ATP to the substrate molecule through transfer of terminal phosphate group.
the vast majority of ATP is generated by
recombining ADP and Pi
