Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

[OBSELETE] Edexcel - A Level Chem > Topic 13 > Flashcards

Topic 13 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

What is standard lattice energy?

A
  • The energy change of a compound
  • When one mole of ionic solid is formed
  • From its gaseous ions
  • UNDER STANDARD CONDITIONS (298K + 100kPa)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What Factors affect lattice energy?

A

Factors that increase lattice energy

  • The higher charge
  • More Cation-Anion[-Cation] interactions
  • The high ionic radii/ion size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the standard enthalpy of atomisation?

A
  • Enthalpy change when measured at
  • Standard conditions (298K 100kPa)
  • For one mole of gas to be produced from its element in its natural state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is electron affinity?

A
  • The energy change
  • When each atom in one mole of atoms
  • In a gaseous state
  • Gains an electron to form an ion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the born harbour cycle?

A

A cycle that shows the energy changes in a reaction such as:

  • Enthalpy change of formation
  • Enthalpy change of atomisation
  • First ionisation energy
  • Electron Affinities
  • Lattice Energy of Ionic Lattice
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the steps for constructing a Born-Haber cycle?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the relationship between the theoretical and the experimental lattice energy values?

A

Theoretical values will always be higher than the experimental values because we assume:

  1. The ions are in contact with each other
  2. Ions are perfectly spherical
  3. There is an even distribution of charge and no covelent characteristics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is there covalency in the ionic bond?

A
  • The cation (+) attracts the electrons on the anion (-)
  • This pulls them towards the cation distorting the electron density of the anion
  • Meaning the Cation POLARISES the Anion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why does polarisation happen between ions?

A
  • Cation (+) attracts the elections on the Anion (-)
  • This pulls the electron towards the cation
  • Distorting the electron density of the Anion
  • Meaning the Cation polarises the Anion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are Fajan’s Rules?

A

Polarisation is increased:
- The high charge density of the Cation
- An Anion with a high charge and big size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Explain this diagram

A
  • The high charge density of the Cation
  • An Anion with a high charge and big size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What it the definition of enthalpy change of solution?

A
  • Determines solubility
  • The enthalpy change when
  • One mole of ionic solid dissolves in water
  • Forming an infinitely dilute solution

Made up from enthalpy of dissociation and hydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is indefinite dilution?

A
  • In dilution ions in a solution move apart (Endo)
  • Ions also become Hydrated (Exo)
  • The Exo and Endo processes affect the enthalpy change of solution referring to an infinitely dilute solution
  • Where after a certain point the value won’t be affected by further dilution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the definition of enthalpy change of hydration

A
  • The enthalpy change
  • When one mole of an ion is in a gaseous state
  • Is completely hydrated by water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the calculations involving the enthalpy of hydration and enthalpy of the solution?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the effect of ionic charge on the enthalpy of hydration?

A
  • The higher the charge
  • The The higher the forces of attraction between the ion and the water molcules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the effect of ionic radii on the enthalpy of hydration?

A
  • An increase in ionic radius
  • Leads to bigger ions
  • With less electrostatic force of attraction between ions and water molecules
  • Meaning the energy released upon hydration decreases
18
Q

What is entropy?

A

The measure of the degree of disorder or randomness of a system

A system is any chemical situation

19
Q

What happens to entropy when the state changes?

A
  • The disorder increases when going from a solid to a liquid
  • The disorder decrease when going from a gas to a liquid
20
Q

What happens to entropy when dissolving a solid lattice?

A
  • The disorder increases when a solid dissolves
  • Meaning an increase in the entropy
21
Q

What happens to entropy when there is a change in the number of moles

A
  • The disorder increases when the number of moles increases
  • The disorder decreases when the number of moles decrease
22
Q

What is the formula for total entropy change?

A
23
Q

What is the formula for entropy change in the system?

A
24
Q

What is the formula for entropy of the surroundings?

A
25
Q

How do you find the temperature from the entropy of the system?

A
26
Q

What is does this diagram show?

A

Dependent on the Gibbs Free Energy calculations

Left to Right

  • When the reaction is endothermic and the entropy is negative the reaction isn’t feasible
  • When the reaction is exothermic and the entropy is negative the reaction may feasible
  • When the reaction is endothermic and the entropy is positive the reaction may be feasible
  • When the reaction is exothermic and the entropy is positive the reaction is definitely feasible
27
Q

What is Gibbs free energy?

A
  • When there is an exothermic reaction which releases energy
  • With the surroundings have been accounted for
  • Any left over energy will be considered free energy
28
Q

What is the formula for Gibbs free energy?

A

If Gibbs free energy is

  • 0 then the reaction is JUST feasible
  • > 0 then the reaction is feasible
  • < 0 then the reaction isn’t feasible

However just because a reaction is feasible you needs time as the rate of reaction is so slow

29
Q

How do you find temperature from enthalpy change

A
30
Q

How does temperature effect a reactions feasibility?

A
31
Q

What does a low Gibbs value mean for the equilibrium constant?

A
  • When Gibb’s free energy is negative
  • The reaction is theoretically feasible
  • The equilibrium constant is greater than 1
  • Meaning that products are favoured over reactants
32
Q

What does a high Gibbs value mean for the equilibrium constant?

A
  • When Gibbs’s free energy is positive
  • The reaction is not theoretically feasible
  • The equilibrium constant is less than 1
  • Meaning that reactants are favoured over reactants
33
Q

What does is mean if the equilibrium constant is very large?

A
  • If K becomes so large
  • Gibbs free energy would become so negative
  • Meaning that reactants are almost entirely converted to completion
34
Q

What is the formular for finding Gibbs from Equilibrium constant?

A
35
Q

What is second electron affinity?

A
  • The enthalpy change when 1 mole of gaseous 2 ions
  • Are made from 1 mole of gaseous 1 ions
36
Q

What is an extended born haber cycle

A

A cycle that shows the energy changes in a reaction such as:
(Endothermic is Up and Exothermic is Down)
- Enthalpy change of formation
- Enthalpy change of atomisation
- First ionisation energy
- Electron Affinities
- Lattice Energy of Ionic Lattice

AS WELL AS
- second ionisation step forming positive ion2+ (endothermic)
- second affinity step forming negative ion 2- (endothermic)

37
Q

What is polarisablity of small cations?

A
  • Small cations are more polarising that larger ones
  • Higher charge density in a smaller area
  • Cation pulls electron towards itself
  • Meaning larger anions will be pulled to the cation
  • MORE POLARISATION = MORE COVALENT CHARACTER
38
Q

What is required for a substance to be dissolved?

A
  • Breaking of bonds (endothermic)
  • New formation of bonds between solvent and substance (exothermic)
  • New bonds must be the same strength or greater then those broken
  • Meaning soluble substances tend to have an exothermic enthalpy
39
Q

What does effect does charge have on the enthalpy charge of hydration?

A
  • Larger charge = stronger attraction of water molecules
  • Due to higher electrostatic attraction
  • More energy released when bond is made which means they have a more exothermic enthalpy of hydration
  • LARGER CHARGE = GREATER ENTALPY OF HYDRATION
40
Q

What does effect does size have on the enthalpy charge of hydration?

A
  • Smaller ion has higher charge density
  • Stronger water molecule attraction
  • Meaning stronger enthalpy of hydration
  • SMALLER ION = GREATER ENTHALPY OF HYDRATION
41
Q

Why can a reaction be feasible if its enthalpy is endothermic?

A
  • Even though reaction is exothermic
  • Changes in entropy can overcome changes in enthalpy
  • Where entropy can outwieght enthalpy
  • Through an increase in moles
  • And enough of a change in states
42
Q

How can equalibrium constants be calculated from gibbs?

A

[OBSELETE] Edexcel - A Level Chem (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions