Thermodynamics

Question 1

a reaction that releases heat is

Answer 1

exothermic

Question 2

a reaction that absorbs heat is

Answer 2

endothermic

Question 3

when H is negative

Answer 3

its exothermic - spontaneous

Question 4

when H is positive

Answer 4

it’s endothermic - non-spontaneois

Question 5

Reactions that increase entropy (+S) tend to be
______

Answer 5

spontaneous

Question 6

reactions that release heat (-ΔH) tend to be

Answer 6

spontaneous

Question 7

measures the energy difference between the products and reactants and takes into account both entropy and enthalpy

Answer 7

gibbs free energy

Question 8

H stands for

Answer 8

Enthalpy change =
heat absorbed or
released

Question 9

T stands for

Answer 9

Temperature

Question 10

S stands for

Answer 10

enthalpy

Question 11

A negative ΔG =

Answer 11

spontaneous reaction

Question 12

A positive ΔG =

Answer 12

a nonspontaneous reaction

Question 13

(-) ΔG

Answer 13

exergonic

Question 14

(+) ΔG

Answer 14

endergonic

Question 15

what is G dependent on?

Answer 15

temperature, pH, relative concentrations of products and reactants

Question 16

Standard Gibbs free energy is calculated at ____ (room
temperature), at a pH of __, at __ M of each reactant and
product -> ΔGo

Answer 16

Standard Gibbs free energy is calculated at 298 K (room
temperature), at a pH of 7, at 1 M of each reactant and
product à ΔGo

Question 17

The following is the first reaction of glycolysis:
§ Glucose + Pi Glucose-6-phosphate
* ΔGoʼ = 12 kJ/mol
Note the positive ΔGoʼ
How is it possible that a reaction with a
(+) ΔGoʼstill occurs in our bodies – all the
time?

Answer 17

This is the whole “rationale” for why the body
phosphorylates ATP (and dephosphorylates it) as a
source of energy currency

• The high-energy phosphodiester bond, when broken,
  has a negative ΔG
• That energy can be coupled to another reaction with a
  positive ΔG
• The net reaction is exergonic…
• if the ΔG of ATP is “negative enough” to counteract
  the endergonic ΔG of the coupled reaction