equations Flashcards
thermal decomposition:
MCO3 (group 2 metal carbonate) —heat—>
MO + CO2
MO (group 1/2 metal oxide) + H2O —>
MOH (metal hydroxide)
M(OH)2 (group 2 metal) —>
MO + H2O
what is the manganate half equation?
MnO4- + 8H+ + 5e- —> Mn2+ + 4H2O
purple —-> pink
what is the dichromate half equation?
Cr2O7 2- + 6e- + 14H+ —> 2Cr3+ + 7H2O
orange —> green
what is the thiosulfate half equation?
2S2O3 2- —> S4O6 2- + 2e-
I2 + 2e- —>
2I-
what equation is it if a question mentions an observation of white precipitate and brown solution?
Cu2+ + 4I- —> CuI + I2
what is the equation for aluminium acting as a base?
Al2O3 + 6HCl —> 2AlCl3 + 3H2O
what is the equation for aluminium acting as an acid?
Al2O3 + 3H2O + 2NaOH —> 2Na[Al(OH)4]
what is the equation for lead acting as a base?
PbO + 2HNO3 —> Pb(NO3)2 + 2H2O
what is the equation for lead acting as an acid?
PbO + H2O + 2NaOH —> Na2[Pb(OH)4]
what is the equation for the reaction of lead with NaOH?
Pb2+ (aq) + 2OH- (aq) —> Pb(OH)2 (s)
forms white ppt
what is the equation for the reaction of lead with excess NaOH?
- white ppt redissolves
- Pb(OH)2 (s) + 2OH- (aq) —> [Pb(OH)4]2-
forms ‘plumbate’ ion
what is the equation for the reaction of aluminium with NaOH?
Al3+ (aq) + 3OH- (aq) —> Al(OH)3 (s)
forms white ppt
what is the equation for the reaction of aluminium with excess NaOH?
Al(OH)3 (s) + OH- (aq) —> [Al(OH)4]-
forms ‘aluminate’ ion
inert pair effect:
Fe2O3 + 3CO —>
2Fe + 3CO2
PbO2 + 4HCl —>
PbCl2 + Cl2 + 2H2O
what is the equation of CO2 as an acidic oxide?
CO2 + H2O —> H2CO3 (weak acid - partial dissociation)
partial dissociation of H2CO3:
H2CO3 ⇌ H+ + HCO3- ⇌ 2H+ + CO3 2-
Pb2+ (aq) + 2Cl- (aq) —>
PbCl2
white ppt
Pb2+ (aq) + 2I- (aq) —>
PbI2 (s)
bright/canary yellow
what is the equation of SiCl4 with water?
SiCl4 + 2H2O —> SiO2 + 4HCl
white fumes produced