lecture 6 Flashcards
characteristics of alkali metals
dissolved in water giving an alkaline solution.
elements in alkali metals
lithium, sodium, potassium, Rubidium, cesium, francium.
what are the most abundant alkali metals.
sodium and potassium.
most rate alkali metals.
rubidium, lithium, cesium
how is alkali metals are extracted?
- electrolysis of molten halides with something that decreases the degree of fusion.
- down process.
extracting sodium
electrophoretic analysis of the photograph with sodium chloride, calcium chloride.
2 NaCl -> 2 Na + Cl2
extracting sodium
electrophoretic analysis of the photograph with sodium chloride, calcium chloride.
2 NaCl -> 2 Na + Cl2
extraction of potassium
sodium vapor with molten potassium chloride.
Na + KCl -> K + NaCl
extraction of lithium
electrophoretic analysis of a mixture of lithium chloride and potassium chloride.
extraction of rubidium and cesium
reduction metal chlorides by calcium
what is the down process.
it’s the process to extract sodium.
how does the down process work?
molten NaCl is electrolyzed and calcium chloride is added to reduce the temperature.
why does the design of the electrolysis unit matter?
because it prevents the sodium and calcium from combining.
why is the metal bonding in alkali metals weak?
because of the attraction between delocalized electrons and the metal ion core in crystalline structures.
physical characteristics of alkali metals.
low melting point and soft consistancy.
reactivity of alkali metals.
highly reactive. and it is a powerful reducing agent,
heat of atomization in alkali metals. as it goes through group.
low and decreases as it goes down the group.
what is the heat of atomization?
the heat required to turn solid to a single gaseous atom.
ionization energy in alkali metals? as it goes through group?
low.
the larger the size, the lower the energy
size of atom in group.
decreases considerably when it loses an electron.
lattice energy of alkali metals as it goes through group.
decreases
relation between atomic radius and force of attraction?
square of atomic radius is inversely proportional to force of attraction.
solubility in alkali metals.
water soluble.
why are alkali metals solube?
because the attraction between the ion and the polar water molecule.
result of mixing water and alkali metal?
highly exothermic reaction. (heat of hydration)
entropy in alkaline metals.
increases as ions disperse into solution.
hydration energy in alkali metals.
decreases as ionic size increases.
normal order of stability vs aqueous ion order of stability
normal -> decreases as ionic size increases.
aqueous ion -> increases.
flame color of alkali metals.
lithium -> red
sodium -> orange
potassium -> lilac
how can alkali metal oxides be obtained. chemical equation.
with limited air supply but it’s better to prepare it by thermal decomposition of peroxides.
4 Li + O2 -> 2 Li2O
example of alkali metal peroxide.
2Na + O2 -> Na2O2
example of alkali metal super oxide.
K + O2 -> KO2
use of alkali metal oxide, peroxide and super oxide.
KO2 is used in breathing masks
as KO2 reacts with water to make oxygen and KOH which absorbs water.
chemical equations for metal oxide and water reacting.
1- M2O + H2O -> 2 MOH
2- M2O2 + 2 H2O -> 2 MOH + H2O2
3- 2 MO2 + 2 H2O -> 2 MOH +H2O2 + O2
4- KOH + CO2 -> KHCO3
how are alkali metals stored? and why.
they submerged in liquid hydrocarbons (oil)
because they react to the weather.
reaction: water and alkali metals
highly reactive with a strong violent reaction.
releases a high amount of energy that ignites the oxygen around it.
alkali metals reacting with acid.
violent. (highly reactive)
metals replace the hydrogen acid.
alkali metals reacting with acid. chemical equation example.
2 Na + 2 HCl -> 2 NaCl + H2
2K + H2SO4 -> K2SO4 + H2
alkali metals reacting with oxygen
creat metal hydride and ionic compound.
alkali metals reacting with oxygen. chemical equation
2 Li + H2-> 2LiH
alkali metals reacting with halides.
direct combination with large negative enthalpy of fusion.
alkali metals reacting with halides. chemical equation
2Na + Cl2 -> 2 NaCl
what is the only alkali metal that reacts with non-metals?
lithium only reacts with nitrogen.
Lithium reacting with nitrogen chemical equation.
6 Li + Cl2 -> 2 Li3N
=> Li3N +3 H20 -> LiOH + NH3
what is potassium nitrite used for and why?
as explosive because it’s a non-wet material and reacts with oxygen.
why can’t sodium nitrate be used for explosives?
because it absorbs water.
what is sodium hydroxides used for? and why.
used in acid equations because it reacts with the acid making salt and water.
real world application of sodium hydroxides.
soap, paper, fabric, oil purification.
potaasium hydride is used for.
batteries.
example of sodium hydroxide being used in the industry,
2 NaCl -[electrolysis]-> 2 NaOH + H2 + Cl2
source of sodium carbonate.
trons ore which is a mix of sodium bicarbonate and sodium carbonate.
sodium carbonate chemical symbol
Na2CO3NaHCO32H2O
solvay process
the process of making sodium carbonate from salt and limestone.
chemical equations for solvay process.
CaCO3 -[heat]-> CaO +CO2
NH3 + CO2+ H2O + NaCl -> NaHCO3 + NH4Cl
2 NaHCO3 -[heat]-> Na2CO3 + H2O + CO2
what is sodium carbonate used for?
glass making, paper, soap, ph regulator.
lithium is used for?
batteries. alloys. medical treatment.
sodium bicarbonate used in.
baking
elemental sodium used in
street lights and nuclear reactors.
