Bonding

Question 1

Answer 1

A

Question 2

Answer 2

I

Question 3

Answer 3

Question 4

Answer 4

Question 5

Answer 5

Question 6

Answer 6

Question 7

Answer 7

Question 8

Answer 8

Question 9

Answer 9

Question 10

Answer 10

Question 11

Answer 11

Question 12

Answer 12

Question 13

Answer 13

Question 14

Answer 14

Question 15

Answer 15

Question 16

Describe the bonding in metals.

Answer 16

Lattice of metal / +ve ions/ cations / atoms (1)
(Surrounded by) delocalised electrons (1)

Question 17

Explain how metals conduct electricity.

Answer 17

(d)
(Delocalised) electrons (1)
Move / flow in a given direction (idea of moving non-randomly)

Question 18

Answer 18

A

Question 19

Answer 19

A

Question 20

Answer 20

Question 21

Suggest why silicon dioxide does not conduct electricity when molten.

Answer 21

No delocalised electrons

Question 22

Deduce the empirical formula of graphane

Answer 22

CH

Question 23

Suggest why graphene is an excellent conductor of electricity.

Answer 23

Delocalised electrons / free electrons
Able to move / flow (through the crystal)

Question 24

Titanium can be hammered into objects with different shapes that have similar strengths.
Suggest why these objects with different shapes have similar strengths.

Answer 24

bonding re-formed / same (metallic) bonding / retains same (crystal) structure / same bond strength / same attraction between protons and delocalised electrons as before being hammered

Question 25

Suggest why the melting point of sodium iodide is lower than the melting point of sodium bromide

Answer 25

Iodide bigger ion so less attraction to sodium ion

Question 26

(b) Describe the structure of and bonding graphite and explain why the mp of it is very high

Answer 26

Layers of carbon atoms
Connected by covalent bonds within each layer
VDW between layers
Many strong covalent bonds need to be broken

Question 27

Answer 27

Question 28

Explain how the ions are held together in solid sodium metal.

Answer 28

Attraction between positive ions and delocalised electrons

Question 29

Explain how the ions are held together in solid sodium chloride.

Answer 29

Electrostatic attractions/forces between opp charged ions

Question 30

(c) Compare the electrical conductivity of solid sodium metal with that of solid sodium chloride.
Explain your answer.

Answer 30

Question 31

Answer 31

Question 32

Answer 32

Question 33

Answer 33

Question 34

Describe the bonding in a crystal of iodine.

Answer 34

covalent between atoms (1)
Van der Waals’ between molecules

Question 35

Name the crystal type which describes an iodine crystal.

Answer 35

Molecular

Question 36

Explain why heat energy is required to melt an iodine crystal.

Answer 36

Bonds (or forces) between molecules must be broken or loosened

Question 37

The heat energy needed to vaporise one mole of sodium chloride (171 kJ mol-1) is much greater than the heat energy required to melt one mole of sodium chloride
Explain why this is so.

Answer 37

All bonds must be broken (1)

Question 38

Why is graphite soft?

Answer 38

Planes (1)
weak (bonds) forces between planes (1)

Question 39

State the block in the Periodic Table in which sulphur is placed and explain your answer.

Answer 39

Block: p (1)
Explanation: Highest energy or outer orbital is (3) p

Question 40

By reference to all the atoms involved explain, in terms of electrons, how Na2S is formed from its atoms.

Answer 40

Clear indication of electron transfer from Na to S (1)
1 e- from each (of 2) Na atoms

Question 41

Draw a diagram, including all the outer electrons, to represent the bonding present in CS2

Answer 41

Question 42

Answer 42

Question 43

Deduce the name or formula of a compound that has the same number of atoms, the same
number of electrons and the same shape as the AICI4- ion.

Answer 43

SiCl4

Question 44

Answer 44

Question 45

Identify one molecule with the same number of atoms, the same number of electrons and the same shape as the H3O+ ion.

Answer 45

NH3

Question 46

Answer 46

Covalent
Shared pair of electrons

Question 47

Suggest one economic problem for the car user caused by incomplete combustion of ethanol in the car engine

Answer 47

More fuel needed (which costs more)/Wastes fuel/
less fuel burnt (so need more to buy more/engine gets sooty so need to pay for engine to be cleaned/Have to fit catalytic converter;

Question 48

(d)
Propane is also used as a fuel, although sometimes it can be contaminated with sulfur-containing impurities. When this propane burns, these impurities form sulfur dioxide.

State how the sulfur dioxide can be removed from the waste gases produced when this propane is burned on a large scale in industry. Suggest a reason why the method you have stated may not be 100% efficient.

Answer 48

(i) (React) with CaO/ calcium oxide/quicklime/lime;

All the sulfur dioxide may not react with the CaO or CaCO,/ may not have time to react/ incomplete reaction;

Question 49

Although propane has a boiling point of -42 °C, it is usually supplied as a liquid for use in camping stoves. Suggest why it is supplied as a liquid.

Answer 49

Occupies a (much) smaller volume;

Question 50

boiling point of AsH3 is -62.5 °C and the boiling point of NH3 is -33.0 °C
Suggest why the boiling point of AsH is lower than that of NH

Answer 50

(t)
(Only) weak Van der Waals forces between molecules /AsH, has weaker IMF /ammonia has hydrogen bonding/ more energy needed to break IMF’s in ammonia/ Van der Waals weaker than H bonds;

Question 51

Explain how the electron pair repulsion theory can be used to deduce the shape of, and the bond angle in, PF3

Answer 51

Question 52

Answer 52

Question 53

Perfume is a mixture of fragrant compounds dissolved in a volatile solvent.
When applied to the skin the solvent evaporates, causing the skin to cool for a short time.
After a while, the fragrance may be detected some distance away. Explain these observations

Answer 53

• Solvent has low bp or weak intermolecular forces or evaporates quickly
• needs energy to evaporate
• energy taken from the skin
• fragrance or perfume slowly spreads
• by diffusion/ random movement