3.1 Energy and the laws of thermo

Question 1

Energy (2)

Answer 1

Capacity to do work or be transferred as heat

Question 2

kinectic energy+ example

Answer 2

energy possessed by an object because it is in motion

waves in an ocean, falling rock, a kicked football

Question 3

potential energy

Answer 3

stored energy
the energy an object has because of its position or chemical structure

Question 4

the potential energy possessed by a specific molecule , its______ is the energy that is _______

Answer 4

chemical energy

stored in the bonds between the atoms that make up the molecule

Question 5

further away from the nucleus the ____ potential energy an electron possesses

Answer 5

more

Question 6

thermodynamics

Answer 6

the branch of science that concerns energy and how it changes during chemical and physical transformations

Question 7

system

Answer 7

object being studied

Question 8

isolated system+ex

Answer 8

one that does not exchange matter or energy with its surroundings.

The universe itself

Question 9

closed system+ ex

Answer 9

can exchange energy but not matter with its surroundings

earth

Question 10

open system+ex

Answer 10

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)

Question 11

first law of thermodynamics + example

Answer 11

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).

Question 12

Second law of thermodynamics +examples

Answer 12

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.

Question 13

Entropy (S) (3)

Answer 13

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.

Question 14

enthalpy (delta h) (3)

Answer 14

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

Question 15

endothermic(3)+ex

overall change of enthalpy,
products what?

Answer 15

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

Question 16

exothermic(3)+ex

overall change of enthalpy,
products what?

Answer 16

a process that releases heat

since the product have less thermal energy than the starting molecules

delta H is neg

Ex: burning of wood

Question 17

Heat and enthalpy relationship at constant temperature

Answer 17

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

Question 18

how changes in both enthalpy and entropy influence the spontaneity of a reaction (2)

Answer 18

1. reactions tend to be spontaneous if they are exothermic; that is if the products have less thermal energy than the reactants.
2. reactions tend to be spontaneous when the entropy of the products is greater then the entropy of the reactions

Question 19

tell me how breaking down of glucose in cellular respiration is spontaneous (2)

Answer 19

• 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

Question 20

whenever a chemical reaction results in an increase in the number of molecules, entropy

Answer 20

increase

Question 21

entropy also increases when: (phase change+why) (3)

Answer 21

solid -> liquid

liquid -> gas

energy is being spread out more readily as matter undergo phase change

Question 22

spontaneous process

Answer 22

a process that can occur without a constant input of energy

Question 23

Gibb’s free energy (2)

-formula

Answer 23

the amount of energy available in a system to do work

delta g= delta H-T(delat S)

Question 24

spontaneous reaction def with Gibbs (3)

Answer 24

the free energy go the product is less than the free energy of the reactions

delat G is negative

exergonic process

Question 25

Tell me if spontaneous or not:
Delta H>0
Delta S>0
delta g= delta H-T(delat S)

Answer 25

spontaneous at high temps

Question 26

Tell me if spontaneous or not:
Delta H>0
Delta S<0
delta g= delta H-T(delat S)

Answer 26

non spontaneous

Question 27

Tell me if spontaneous or not:
Delta H<0
Delta S<0
delta g= delta H-T(delat S)

Answer 27

spontaneous at low temp

Question 28

Tell me if spontaneous or not:
Delta H<0
Delta S>0
delta g= delta H-T(delat S)

Answer 28

spontaneous

Question 29

exergonic process (2)

Answer 29

a spontaneous process
delta g is negative

Question 30

endergonic process (2)

Answer 30

a non-spontaneous reaction
delta g is positive

Question 31

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 _____

Answer 31

is exergonic or endergonic,

activation

Question 32

exergonic reactions move towards _____ but do not go to _______

Answer 32

equilibrium

completion

Question 33

Why not to completion? (3)

Answer 33

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

Question 34

metabolism

Answer 34

The collection of all the chemical reactions present within a cell or organism

Question 35

many different metabolic reactions take place within a cell resulting in

Answer 35

the synthesis or breakdown of a huge variety of molecules

Question 36

catabolic pathway (3)+ex

Answer 36

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

Question 37

anabolic pathway(2)+ex

Answer 37

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

Question 37

The energy acquired through______ is used to drive _______

Answer 37

catabolic processes

anabolic processes

Question 38

the specific form of chemical energy that most often. links the two type of pathways is the molecule___

Answer 38

ATP

Question 39

ATP-ADP vice versa equation

Answer 39

Question 40

Explain why ATP generates and the process is used(2)

Answer 40

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.

Question 41

energy coupling

Answer 41

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.

Question 42

energy coupling during metabolism requires an enzyme that binds to both a (3)

Answer 42

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.

Question 43

the vast majority of ATP is generated by

Answer 43

recombining ADP and Pi