redox and group 1, 2 and 7 Flashcards
Ba(2+) flame test colour
apple green
Ca(2+) flame test colour
brick red
Cu(2+) flame test colour)
green blue
Li(+) flame test colour
red
K(+) flame test colour
lilac
Na(+) flame test colour
yellow orange
Sr(2+) flame test colour
red
Group 2 reaction with chlorine
X + Cl2 -> XCl2
group 2 reaction with oxygen
X + O2 -> 2XO (exception: Ba + O2 -> BaO2)
group 2 reaction with water
X + 2H2O -> X(OH)2 + H2
group 2 oxide and weak acid
XO + 2HCl -> XCl2 + H2O
group 2 oxide and water
XO + H2O -> X(OH)2
group 2 hydroxide and weak acid
X(OH)2 + HCl -> XCl + 2H2O
trend in hydroxide solubility down group 2
hydroxides are more soluble as they go down the group
trend in sulphate solubility down group 2
sulphates are less soluble down the group
group 1 nitrate thermal decomposition
2NaNO3 -> 2NaNO2 + O2
lithium behaves like G2 bc charge dense
group 2 nitrate thermal decomposition
Lower charge density than group 1 cation
covalent bonds are not polarised so nitrite is formed
2Mg(NO3)2 -> 2MgO + 4NO2 + O2
brown gas (NO2) bleaches KMnO4 paper and relights glowing splint
experiment method for hydrolysis of halogenoalkanes
ethanol as solvent
equal volume of halogenoalkanes
add silver nitrate
measure time taken for ppt to form
use water bath yo ensure constant temp
trend in hydrolysis of of chloro ,bromo and iodobutane
chloro slowest, iodo fastest
explain trend in hydrolisis of group 7 halogenoalkanes
C-Cl bond is strongest
Write an equation for the disproportionation reaction between chlorine and hot alkali
3Cl2 (g) + 6NaOH (aq) -> 5NaCl (aq) + NaClO3 (aq) + 3H2O (l)
Write an equation for the disproportionation reaction between chlorine and cold dilute aqueous sodium hydroxide
Cl2 + 2NaOH (aq) -> NaClO (aq) + H2O (l) NaCl (aq)
NaCl and NaClO combine to make bleach
Write an ionic half equation for the oxidation of chlorine molecules to chlorate (I) ions in the presence of cold aqueous hydroxide ions.
Cl2 + 4OH- -> 2ClO- + 2H2O + 2e-
Bromine can be extracted from sea water containing bromide ions using chlorine.
Write the ionic equation for this reaction
Cl2 + 2Br- -> Br2 + 2Cl-
Explain why iodine and chlorine has similar chemical reactions
Both have 7 e- in outer shell
Electronic configuration governs chemical reactions
Why does calcium nitrate require a higher temperature for decomposition than magnesium nitrate
Ca2+ larger ionic radius (less charge dense)
Ca2+ less polarisation and bing distortion
Of the N-O bond in the anion
Observation when NH4Br produced
White smoke
Reasons for difference in rate of reaction between barium and strontium with water dur to ionisation energies
Barium loses outer e- easier
Barium has larger atomic radius
More shielding in barium
This has greater influence than
Barium having more protons
Barium is more reactive
What anion forms a crown gas that relights a glowing splint
NO3-
Which halogen ion has the strongest reducing power (out of Cl- Br- I-)
I- strongest reducing agent
