Up Learn – A Level Chemistry (aqa) – Thermodynamics
Entropy: Order and Disorder
Theoretical lattice enthalpy calculations are based on the perfect ionic model, which assumes that the bonding in salts is 100% ionic.
More videos on Thermodynamics:
Positive and Negative Entropy Changes
Predicting Entropy Changes of Reactions
Entropy change formula: Calculating Entropy Changes
Why are the units of entropy change ‘per mole’?
Gibbs Free Energy: Why do some Feasible Reactions not happen?
Units of Gibbs Free Energy Change
Calculating Gibbs Free Energy Change
Gibbs Free Energy: Feasibility
Finding Entropy and Enthalpy from Gibbs vs. Temperature Graph
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Thermodynamics
2. Order and Disorder
3. What is Entropy?
4. How Does Temperature Affect Entropy?
5. How Does State Change Affect Entropy?
6. Comparing Entropy Between Substances?
6. How Does Dissolving a Substance Affect Entropy?
8. How Does the Number of Particles Affect Entropy?
9. Entropy Changes
10. Predicting the Entropy Change of a Reaction 1
11. Predicting the Entropy Change of a Reaction 2
2. A Simple System 1
3. A Simple System 2
4. Relating Configurations to Entropy
5. The Exact Mathematical Definition of Entropy
6. Relating Our Simple System to Atomic Systems
7. Why Does Temperature Affect Entropy?
8. Why Does Number of Particles Affect Entropy?
9. Why Does State Affect Entropy?
10. So Is Entropy Really a Measure of Disorder?
2. Measuring Entropy for Larger Systems
3. Entropy at Absolute Zero
4. Explaining Entropy at 0 K Mathematically
5. Entropy at Non-Zero Temperatures
6. Graphing Entropy
7. Standard Molar Entropies
8. Investigating the Trends in the Table of Absolute Entropies
9. Calculating the Entropy Change of a Reaction
10. Why Did We Bother Predicting Entropy Changes in the First Place?
11. Why Are the Units of Entropy Change ‘Per Mole’?
2. The Entropy Change of the Surroundings
3. Calculating the Entropy Change of the Surroundings
4. The Entropy Change of the Universe
5. What Reactions Can’t Happen?
6. Feasibility
7. Why Do Some Feasible Reactions Not Happen?
8. The 2nd Law of Thermodynamics
9. Gibbs Free Energy Change
10. The Units of Gibbs Free Energy Change
11. Calculating Gibbs Free Energy Change
12 .Assessing Feasibility
13. Assessing Feasibility – Making Ice
14. Assessing Feasibility – Thermal Decomposition of Calcium Carbonate
15. Exam Technique: Explaining Feasibility
16. Graphing Gibbs Free Energy Change
17. Using Graphs to Find Enthalpy and Entropy Changes
18. Assessing Feasiblility from Graphs
19. Finding the Temperature Where Reactions Become Feasible
20. The Limitations of Our Temperature-Finding Equation
21. Doesn’t Entropy Change…. Change With Temperature?
22. Calculating Gibbs Free Energy Change for Reverse Reactions
23. What About Reversible Reactions?
24. How Are Reversible Reactions Compatible With the Second Law of Thermodynamics?
Last time, we said it’s not just enthalpy that determines whether reactions can happen…
That something called entropy plays a role too.
Unfortunately, defining entropy is a little tricky.
And so, rather than talking about entropy straight away, we’re first going to talk about disorder…
For example, we’d say these bricks are more disordered than these bricks.
We’d say that these trees are more disordered than these trees.
And we’d say this kitchen cupboard is more disordered than this kitchen .
Really, disorder is just the opposite of order. If things are ordered, they might be neatly arranged, put into groups and so on. If they’re disordered, not so much.
So now, for each of these pairs, decide which is the more disordered.
These are all more disordered than their counterparts.
Now, having a sense of what disorder means is going to help us get a very rough sense of what entropy is…and so we’ll look at entropy, next…
But to sum up for now, disorder is just the opposite of order.