5D lattice enthalpy change

What is lattice enthalpy change

The enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions

What is enthalpy of ionisation energy

The enthalpy change required to remove one electron from each atom/ion in a mole of gaseous atoms/ions to form one mole of gaseous ions of equal charge

What is enthalpy of electron affinity

The enthalpy change required to add one electron to each atom/ion in a mole of gaseous atoms /ions to form one mole of gaseous ions with an equal charge

What is enthalpy of atomisation

The enthalpy change when one mole of gaseous atoms is formed from an element in its standard state under standard conditions

What is enthalpy change of formation

The enthalpy change that takes place when one mole of a substance is formed from its elements under standard conditions

How does born Haber cycle work

Structure of born haber cycle

What is standard enthalpy change of solution

The enthalpy change when one mole of solute dissolves to form a dilute solution

What is standard enthalpy change of hydration

The enthalpy change when one mole of gaseous ions forms a solution

What happens when an ionic solid dissolves in water

Ionic lattice breaks up to release ions

Ions bond to water molecules forming the solution

Changes that may occur from solid ions going to aqueous ions

Solid ions to gaseous ions

Gaseous ions to aqueous ions

Is lattice enthalpy endothermic or exothermic?

Why?

Exothermic - because bonds are being formed

Is standard enthalpy of hydration endothermic or exothermic?

Why?

Exothermic - gaseous ions are forming bonds with water molecules

is enthalpy change of solution endothermic or exothermic

Can be either

How do you calculate lattice enthalpy, enthalpy of solution or enthalpy of hydration

How to calculate enthalpy of solution

Q= m x c x delta t (change in temp) Solution mass x 4.18 x change in temp.

Mass of salt or mr to get moles

Do q/moles

Change sign

What are the factors that affect standard lattice enthalpy and enthalpy of hydration

Charge density - dependant on ionic radius or charge of ion

The smaller the radii and higher the charge means greater charge density

For standard lattice enthalpy the smaller the ionic radius and higher the charge means what

The greater the charge density of ions and stronger electrostatic attraction between ions so standard lattice enthalpy is more exothermic

For standard enthalpy of hydration the smaller the ionic radius and higher the charge means what

Greater charge density of ions involved

Stronger electrostatic attractions formed between ions formed between ions and water molecules so more exothermic

What is entropy

The quantitative measure of the degree of disorder in a system, the higher the entropy the more disordered the system is

Entropy units and equation

What has the most entropy solids liquids or gases

Gases = most

Liquids/ aqueous substances = middle

Solids = least

When talking about entropy talk about what

The disorder of the reaction and dispersal of energy

Do solids increase or decrease dispersal of energy

Decrease

What happens to entropy if moles of gas increases

Entropy increases

Predict entropy sign

If solids mention decrease in dispersal energy and decrease in disorder so delta S is negative

If gases mention an increase in dispersal energy and disorder so delta S is positive

What is Gibbs equation

Delta G = free energy change

Delta H = enthalpy of reaction

T = temperature

Delta S= entropy

Units in gibbs equation

Delta G = kj mol ^-1

Delta H = kJ mol ^-1

Delta S is J so need to divide by 1000 to get kj k^-1 mol^-1

T = Kelvin

What is a feasible reaction

A reaction that is energetically possible

How do we know if a reaction is feasible

Delta G must be negative delta G<0

So of negative = feasible

If positive = not feasible

How do you calculate minimum temperature with gibbs equation

Delta H / Delta S

Explain question

Delta H is positive

Delta S is positive

Because reaction is feasible at high temperatures

In this case T delta S increases with temperature

At high temperatures delta G <0

At low temperatures delta G> 0