Unit 7 Flashcards
Amine,s Carboxylic derivatives
What is lattice energy and lattice enthalpy?
The energy change when one mole of a crystal is formed from ions is gas state.
lattice enthalphy- heat released when one mole of solid in its standard state is formed from ions in gaseous state
Can you find lattice enthalpy directly?
No must use Hess’ law
What is Hess’s law?
The enthalpy of a reaction will be the same no matter the reactions used (pathway doesn’t matter)
What does a more negative value of lattice enthalpy mean?
The bond was more energetically stable
What does it mean if there is a big difference between values achieved using the born lande equation and a born haber cycle (hess) ?
A big difference means significant covalent bonding
What is polymorphism?
When a substance can exist in more than one form when both forms are stable its called enantiotropy
Can diamond and graphite conduct electricity?
Diamond cant graphite can conduct electric
Diamond will change to the more stable form graphite, but this process is so slow it appears stable, what is this called?
Metastable
What is chemical equilibrium?
When the rate of the forward reaction is equal to the rate of the backward reaction. Concentrations of reactants and products will be steady
How do you work out equilibrium constant?
Concentrations (gasses pressure) of products over reactants
products/reactants
Raise the concentrations to the power of their moles
What is Le Chatliers principle?
If conditions of an equilibrium are changed the system will adjust itself to counteract the affect
Does a catalyst have affect on an equilibrium?
No the proportions of products and reactants wont change, so Kc wont be affected
For an endothermic reaction what will an increase in temperature favour?
Favour formation of products
For an exothermic reaction what will an increase in temperature favour?
Reactants
How do you determine equilibrium constant experimentally?
Must reach equilibrium
Temperature must be constant
Concentrations must be known
