Entropy and Spontaneous Changes Flashcards
1
Q
Spontaneous Change
A
- Continues to progress forward on its own once it has begun
2
Q
Spontaneous Change Example
A
- Lighting a match
- Strike it once, flame continues until reactants are gone
3
Q
Non-Spontaneous Change
A
- Cannot occur without a continual input of energy
4
Q
Non-Spontaneous Change Example
A
- Boiling a pot of water
- Removing the heat stops the boiling
5
Q
What can the concept of spontaneity help us determine?
A
- How likely it is for certain reactions to take place
- Important in biological systems where reactions need to be highly controlled
6
Q
What factors of the table are favoured?
A
- Exothermic Changes
- Increase in Entropy
7
Q
What factors of the table are not favoured?
A
- Endothermic Changes
- Decrease in Entropy
8
Q
Exothermic Changes + Increase in Entropy
A
- Spontaneous at all temps
- Ex. Wood burning, food colouring dispersing in water, cell respiration
9
Q
Exothermic Changes + Decrease in Entropy
A
- Rare
- Spontaneous at low temps
- Not spontaneous at high temps
- Ex. Water freezing
10
Q
Endothermic Changes + Increase in Entropy
A
- Spontaneous at high temps
- Not spontaneous at low temps
- Ex. Sweat evaporating from skin, ice melting
11
Q
Endothermic Changes + Decrease in entropy
A
- Not spontaneous at any temp
- Requires continuous input of energy to move forward
- Ex. Plants making glucose (photosynthesis), rolling a ball uphill
12
Q
Who is Josiah Gibbs?
A
An American scientist that described “free energy” in 1873
13
Q
What is Free Energy?
A
- Energy available to do useful work
14
Q
What is Free Energy used for in living organisms
A
- Anabolism, reproduction and movement
- Needed to do chemical and physical work
15
Q
Formulas to calculate the change in free energy (△G)
A
- △G=△H-T△S
- △G=G final state - G initial state
