Topic 4 - inorganics

Question 1

How does ionisation energy change down group 2?

Answer 1

Decreases as more shielding

Question 2

How does group 2 from Be - SR react with oxygen?

Answer 2

All burn vigorously except Be. 2M + O2 –> 2MO

Question 3

How does Barium react with oxygen?

Answer 3

Vigorously. Ba + O2 –> 2BaO2

Question 4

What is the trend on reactions of group II with water? and comparison to group 1?

Answer 4

Group 2 less reactive than comparative group 1. Increases in vigour down the group.

Question 5

What is the equation for Mg and water?

Answer 5

Mg + H2O –> MgO + H2

Question 6

What is the equation for Ca, Sr or Ba in water?

Answer 6

M + 2H2O –> M(OH)2 + H2

Question 7

Explain water happens with Be and water?

Answer 7

Beryllium doesn’t react with water

Question 8

What is the equation for group II and chlorine?

Answer 8

M + Cl2 –> MCl2

Question 9

How do group II oxides react with water?

Answer 9

Form M(OH)2 except BeO

Question 10

How do group II oxides react with dilute acids?

Answer 10

Forms salt and water

Question 11

Why do group II hydroxides react with acids?

Answer 11

They are bases

Question 12

How does group II sulphates solubility change?

Answer 12

Less soluble down the group.

Question 13

How does group II hydroxides solubility change?

Answer 13

More soluble down group. All partially soluble

Question 14

What changes the thermal stability of carbonates?

Answer 14

More stable = stronger CO bond = anion polarised less = large cation = more stable down group

Question 15

How does thermal stability of group 1 carbonates change?

Answer 15

Li not stable under bunsen heat(Li2CO3 –> Li2O + CO2). All others are increasingly more stable

Question 16

How does thermal stability of group 2 carbonates change?

Answer 16

More stable down group but, all decompose under heat to form MCO3 –> MO + CO2

Question 17

How does group II thermal stability of nitrates change down group?

Answer 17

More stable down group. Forms 2MO + 4NO2 + O2

Question 18

How does group 1 thermal stability of nitrates change?

Answer 18

More stable down group. All decompose (except Li) to MNO2 + O2. Lithium forms Li2O + NO2 + O2

Question 19

What are the flame tests of group 1 and II?

Answer 19

LI+ - Red. Na+ - yellow. K+ - Lilac. Ca2+ - Brick red. Sr2+ - Crimson. Ba2+ - Apple green

Question 20

What is chlorine’s appearance at rtp, in aq solution and hydrocarbon solution?

Answer 20

Green gas at rtp. Pale green in solutions.

Question 21

What is Bromine’s appearance at rtp, in aq solution and hydrocarbon solution?

Answer 21

Red/Brown liquid at rtp. Orange/Yellow in aq. Red in hydrocarbon solution.

Question 22

What is Iodine’s appearance at rtp, in aq solution and hydrocarbon solution?

Answer 22

Grey/black solid at rtp. Brown in aq. Violet in hydrocarbon solution.

Question 23

How does electronegativity change down group 7?

Answer 23

Decreases down the group as bigger element less electronegative.

Question 24

How does mtp change for group 7?

Answer 24

Increases down group as more London forces.

Question 25

What is noticeable about group 7 reactions with metals and non-metals?

Answer 25

More exothermic up the group with metals. More explosive up group with non-metals. E.g. Chlorine + H2 exlplode in sunlight, bromine needs catalyst and Iodine is very slow.

Question 26

How do group 7 act as oxidising agents?

Answer 26

Stronger oxidising agents up group as gain e- more easily.

Question 27

How do group 7's reactions with conc. H2SO4 change?

Answer 27

Better reducing agents down group as lose electron more easily. Meaning HI and HBr form I2 and Br2 but KCl only forms HCl

Question 28

How do you test for a halide?

Answer 28

Add nitric acid and silver nitrate. Cl- forms white ppt. Br- cream and I- yellow.

Question 29

How can you test halide ppts after silver nitrate test?

Answer 29

Add ammonia solution, AgCl dissolves, AgBr only in conc. and AgI doesn't.

Question 30

Are hydrogen halides soluble?

Answer 30

Yes, in water for acids.

Question 31

Why don't we use Astatine?

Answer 31

It is radioactive

Question 32

Test for carbonate ion?

Answer 32

Add dilute acid, test gas with limewater. Goes cloudy as CO2 produced.

Question 33

Test for sulfate ion?

Answer 33

Add dilute HCl to solution followed by Barium Chloride. Forms white ppt.

Question 34

Test for Ammonium ion?

Answer 34

Warm with NaOH. Hold damp red litmus. Ammonia gas turns it blue