Unit 4- Entropy Flashcards
State the two laws of thermodynamics
Energy cannot be created or destroyed
Entropy always increases in the transformation of energy
What is entropy
The measure of order in a system measured in J per mol per kelvin
How does entropy increase?
It increases when you move towards more disorder therefore it increases from Solid - liquid - gas.
Complexity also affects it as the more complex, the greater the entropy
What is spontaneuos/feasible reaction?
when a reaction occurs without any external energy applied
enthalpy and entropy both affect whether a reaction is spontaneuous
What is the entropy in the following scenarios-
- Dissolving a solid
- production of a gas
- exothermic reactions that produce a solid
- endothermic reaction between two solids
- level of disorder increases therefore entropy increases
- gas has a greater disorder therefore increase in entropy
- gas to solid therefore entropy decrease
- depends on physical states of compounds
What makes a reaction spontaneus
if Delta S total is greater than 0
Define lattice energy
the energy required to break an ionic crystal into seperate ions in a gaseous state
Define Delta Hydration
the energy released when 1 mole of a gaseuos ions is dissolved in water to produce a solution of 1mol per dm^3
Define Delta Solution
the enthalpy change when 1 mole of the compoind dissolves in a stated amount of water
What determines the solubility of an ionic compound?
When the Delta Hydration is greater than Lattice energy the compoind dissolves in water.
