redox and group 1, 2 and 7

Question 1

Ba(2+) flame test colour

Answer 1

apple green

Question 2

Ca(2+) flame test colour

Answer 2

brick red

Question 3

Cu(2+) flame test colour)

Answer 3

green blue

Question 4

Li(+) flame test colour

Answer 4

red

Question 5

K(+) flame test colour

Answer 5

lilac

Question 6

Na(+) flame test colour

Answer 6

yellow orange

Question 7

Sr(2+) flame test colour

Answer 7

red

Question 8

Group 2 reaction with chlorine

Answer 8

X + Cl2 -> XCl2

Question 9

group 2 reaction with oxygen

Answer 9

X + O2 -> 2XO (exception: Ba + O2 -> BaO2)

Question 10

group 2 reaction with water

Answer 10

X + 2H2O -> X(OH)2 + H2

Question 11

group 2 oxide and weak acid

Answer 11

XO + 2HCl -> XCl2 + H2O

Question 12

group 2 oxide and water

Answer 12

XO + H2O -> X(OH)2

Question 13

group 2 hydroxide and weak acid

Answer 13

X(OH)2 + HCl -> XCl + 2H2O

Question 14

trend in hydroxide solubility down group 2

Answer 14

hydroxides are more soluble as they go down the group

Question 15

trend in sulphate solubility down group 2

Answer 15

sulphates are less soluble down the group

Question 16

group 1 nitrate thermal decomposition

Answer 16

2NaNO3 -> 2NaNO2 + O2

lithium behaves like G2 bc charge dense

Question 17

group 2 nitrate thermal decomposition

Answer 17

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

Question 18

experiment method for hydrolysis of halogenoalkanes

Answer 18

ethanol as solvent
equal volume of halogenoalkanes
add silver nitrate
measure time taken for ppt to form
use water bath yo ensure constant temp

Question 19

trend in hydrolysis of of chloro ,bromo and iodobutane

Answer 19

chloro slowest, iodo fastest

Question 20

explain trend in hydrolisis of group 7 halogenoalkanes

Answer 20

C-Cl bond is strongest

Question 21

Write an equation for the disproportionation reaction between chlorine and hot alkali

Answer 21

3Cl2 (g) + 6NaOH (aq) -> 5NaCl (aq) + NaClO3 (aq) + 3H2O (l)

Question 22

Write an equation for the disproportionation reaction between chlorine and cold dilute aqueous sodium hydroxide

Answer 22

Cl2 + 2NaOH (aq) -> NaClO (aq) + H2O (l) NaCl (aq)
NaCl and NaClO combine to make bleach

Question 23

Write an ionic half equation for the oxidation of chlorine molecules to chlorate (I) ions in the presence of cold aqueous hydroxide ions.

Answer 23

Cl2 + 4OH- -> 2ClO- + 2H2O + 2e-

Question 24

Bromine can be extracted from sea water containing bromide ions using chlorine.
Write the ionic equation for this reaction

Answer 24

Cl2 + 2Br- -> Br2 + 2Cl-

Question 25

Explain why iodine and chlorine has similar chemical reactions

Answer 25

Both have 7 e- in outer shell
Electronic configuration governs chemical reactions

Question 26

Why does calcium nitrate require a higher temperature for decomposition than magnesium nitrate

Answer 26

Ca2+ larger ionic radius (less charge dense)
Ca2+ less polarisation and bing distortion
Of the N-O bond in the anion

Question 27

Observation when NH4Br produced

Answer 27

White smoke

Question 28

Reasons for difference in rate of reaction between barium and strontium with water dur to ionisation energies

Answer 28

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

Question 29

What anion forms a crown gas that relights a glowing splint

Answer 29

NO3-

Question 30

Which halogen ion has the strongest reducing power (out of Cl- Br- I-)

Answer 30

I- strongest reducing agent