Unit 4- Entropy Flashcards
(19 cards)
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.
