9 group 2 Flashcards
what happens to atomic radius down group 2?
increases
what happens to 1st ionisation energy down group 2?
decreases
why does 1st and 2nd ionisation energy decrease down group 2?
more shielding so the outer electrons are further from the nucleus
what happens to melting points down group 2?
general decrease
what happens when group 2 elements react with water?
form metal hydroxide
what is the equation for the reaction with Sr and H2O?
Sr (s) + 2H2O (l) -> Sr(OH)2 (aq) + H2 (g)
what happens to the solubility of group 2 hydroxides down the group?
solubility increases
what happens when you react Mg with steam?
more vigorous reaction
Mg (s) + H2O (g) -> MgO(s) + H2 (g)
what happens to group 2 sulfates down the group?
solubility decreases
how do you test for sulfates?
- add HCl
- add BaCl
- white precipitate present=positive result
why do you add HCl before BaCl when testing for sulfates?
to remove any carbonates that could give a false result
what can group 2 compounds neutralise?
acids
what can neutralise acidic soil?
Ca(OH)2
what can neutralise stomach acid?
Mg(OH)2
what is the ionic equation for neutralisation?
H+ (aq) + OH- (aq) -> H2O (l)
what compound is a barium meal?
BaSO4
how does a barium meal work?
- patient drinks barium sulfate
- lines soft tissues like the stomach
- helps with identifying problems with the digestive tract
why can we drink barium sulfate if it is toxic?
insoluble so cannot be absorbed into blood
what is the equation for extracting titanium from magnesium?
TiCl4 + 2Mg -> Ti + 2MgCl2
what toxic compound is in flue gases?
SO2
what 2 compounds can be used to remove SO2 from flue gases?
CaCO3 or CaO
what is the process of removing SO2 from flue gases called?
wet scrubbing
what are the 2 equations for wet scrubbing?
CaCO3 + 2H2O + SO2 -> CaSO3 + 2H2O + CO2
CaO + 2H2O + SO2 -> CaSO3 + 2H2O
