PHYSICAL Flashcards
What does the strength of an ionic lattice depend on?
the charge of ions and the size of ions
Enthalpy of formation is the opposite of
enthalpy of separation
What is the enthalpy of atomisation?
The enthalpy change when one mole of gaseous atoms are formed from an element in its standard state.
What is the enthalpy change of separation
The enthalpy change of separation is the enthalpy change when one mole of an ionic compound is separated into its constituent elements in their standard state
What is the enthalpy change of separation
The enthalpy change of separation is the enthalpy change when one mole of an ionic compound is separated into its constituent elements in their standard state
Enthalpy of atomisation and bond dissociation can be related when?
gaseous AND covalently bonded in its standards state
What is the standard state of bromine?
liquid
What is the standard state of iodine?
solid
What is the difference between 1st and 2nd etc electron affinities?
The 1st IE is exothermic subsequent ionisation energies are endothermic
How do you work out born haber cycles?
Take notice of the amount of moles of each element in the compound
(3 arrows up, 3 down, down arrows are the first arrow on the left and the arrows on the right MOSTLY)
Add atomisations
add ionisation energies of metal
add electron affinities of the gas
ADD the formation enthaly (multiply by minus on to make it positive)
Multiply answer by minus one
Which moel suggest that all acids and bases are soluble in water?
arrhenius
Which model suggests that a substance can be an acid in one reaction and a base in another?
bronsted lowry
Which model suggest that every substance can be classified as an acid or a base?
bronsted lowry
What is a bronsted lowry base?
A proton acceptor
What is an Arrhenius acid?
a substance that dissolves in water to produce protons
Whats the difference between a conjuagte acid and a conjugate base?
the conjugate acid has an extra proton
Why is the enthalpy of hydration always exothermic
ion dipole forces are made whilst there are no bonds between gaseous molecules
What does hydration enthalpy depend on?
size of ion
magnitude of charge
How does a hydration thermochemical diagram look?
3 arrows down one up for sol. Ions at the top, solids at the bottom
Higher Kc = higher amount of?
products at equillibrium
Which reactions are feasible?
reactions which increase the entropy of the universe where entropy of the universe is entropy of surr + entropy of system
The equation for gibbs free energy is
\Delta G=\Delta H-T\Delta S
How is molecular entropy measured?
Enthalpy of products - reactants
How do you go from a hydrated salt to a anhydrous salt?
vigorous heating
Why cant an anhydrous salt be converted into a hydrated salt in one step?
an exact amount of water hsa to be added and there is no guarantee taht it will be distrubuted evenly
How can you test for sulfate ions?
Us barium chloride and a white precipitate will for, as barium sulfate is almost insoluble
What is the only way that F and Cl react with sulfuric acid?
Acid base reaction Misty fumes
How is does sulfurs oxidation number change when it reacts with bromine?
from +6 in H2SO4 to +4 in SO2
Solid sulfur is a ?
Yellow solid
Which gas smells like rooted eggs?
H2S
How can I test for different halides ?
Dissolve the halide in water to form an aqueous solution Add drops of Silvernitrate
AgF dissolves AgCl white AgBr Cream AgI pale yellow
Why do u add dilute nitric acid when testing for halides?
To remove impurities such as carbonate ions and hydroxide ions which also for, white precipitates
How can I differentiate between AgCl AgBr and AgI
Add dilute ammonia AgCl dissolves then add conc Ammonia AgBr will dissolve AgI will is insoluble in any concentration of ammonia
