Lecture 3/01.17.25 Flashcards
(29 cards)
What is free energy(delta G)?
The process that tell us whether we will require or release energy
What can the release of energy do?
It can do cellular work: protein synthesis, folding of proteins, transport across membranes, ATP, etc.
What is a system?
A part of the universe that we choose to study. Ex: petri dish with cells, single cell bacteria, etc.
What is a surrounding?
Anything that is not defined as being a part of the system
What can a system be?
Closed, isolated, and open
What does it mean for a system to be isolated?
It means it is unable to exchange energy or matter with surroundings
What does it mean for a system to be closed?
It means that it is able to exchange energy but not matter with surroundings. Ex: Our planet
What is the first law of thermodynamics?
The total energy of an isolated system is constant. In short, it cannot be created nor destroyed but it can be transferred
What does it mean for a system to be open?
It means that it is able to exchange energy and matter with surroundings, this is typically what we see in organisms
What is the second law of thermodynamics?
The total entropy of a system plus its surroundings always increases
What is enthalpy?
It is the measurement of the total energy in a system
What is entropy?
The drive to randomness which can be the ability of a molecule to rotate/vibrate/twist around, how molecules are scattered or ordered, or how large molecules vs. small molecules. The equation is S= S(system)+S(surroundigs)
What is true about a negative G?
It can do work and is favorable but the reverse process is not favorable. Also an exergonic reaction/spontaneous.
What is true about a value of 0 in G?
There is zero work and the process is reversible and at equilibrium
What is true about a positive G?
It means that work is required and is unfavorable and the reverse process is favorable. Also an endergonic reaction and no spontaneous(L->R)
What does a negative H mean?
It is losing heat and is favorable
What does a positive H mean?
It is taking heat to make the reaction proceeding
What does a positive S mean?
Gaining entropy and is favorable
What does a negative S mean?
It means it is losing entropy which is not favorable
What is true about reversible and irreversible reactions?
Theoretically, ALL reactions are reversible, but the directionality depends on concentrations of products and reactants. If G is small then the direction can be reversible but if large then it may be irreversible. If G=0 then for/rev. is happening at the same time.
What is true about the value of G?
It is not a fixed value for a given reaction except under standard conditions which are reactants and products at 1.0 M, 25 C, and pH at 7.0. This is also known as G(naught)’
What is standard free energy?
G(naught)’
How can G(naught)’ be calculated?
Can be determine by measuring conc. of reactants and products
What is true about energy change and energy?
It determines if a reaction will proceed in one direction or occur in the reverse direction
