3.1.3 Bonding PPQs

Question 1

describe the structure of iron oxide and the attraction broken when it is melted or boiled.

Answer 1

Structure: Giant ionic lattice
Attraction: Electrostatic attraction between oppositely charged ions

Question 2

describe the structure of CH3SH and the attraction broken when it is melted or boiled.

Answer 2

Structure: Simple molecular
Attraction: Covalent bonding between atoms

Question 3

describe the structure of graphite and the attraction broken when it is melted or boiled.

Answer 3

Structure: Macromolecular
Attraction: Covalent bonding between atoms

Question 4

describe the structure of sodium bromide and the attraction broken when it is melted or boiled.

Answer 4

Structure: Giant ionic lattice
Attraction: Electrostatic attraction between oppositely charged ions

Question 5

describe the structure of magnesium and the attraction broken when it is melted or boiled.

Answer 5

Structure: Giant metallic lattice
Attraction: Electrostatic attraction between positive ions and delocalised electrons

Question 6

describe the structure of diamond and the attraction broken when it is melted or boiled.

Answer 6

Structure: Macromolecular
Attraction: Covalent bonding between atoms

Question 7

describe the structure of PF3 and the attraction broken when it is melted or boiled.

Answer 7

Structure: Simple molecular
Attraction: Intermolecular attractions between molecules

Question 8

describe the structure of CH3Br and the attraction broken when it is melted or boiled.

Answer 8

Structure: Simple molecular
Attraction: Intermolecular attractions between molecules

Question 9

describe the structure of H2O and the attraction broken when it is melted or boiled.

Answer 9

Structure: Simple molecular
Attraction: Intermolecular attractions between molecules

Question 10

describe the structure of barium and the attraction broken when it is melted or boiled.

Answer 10

Structure: Giant metallic lattice
Attraction: Electrostatic attraction between positive ions and delocalised electrons

Question 11

what is the ionic formula for potassium nitride

Answer 11

K3N

Question 12

what is the ionic formula for Rubidium Chlorate (I)

Answer 12

RbClO

Question 13

what is the ionic formula for Calcium Dichromate

Answer 13

CaCr2O7

Question 14

what is the ionic formula for Calcium Hydroxide

Answer 14

Ca(OH)2

Question 15

what is the ionic formula for Zinc Carbonate

Answer 15

ZnCO3

Question 16

what is the ionic formula for Strontium Sulphate

Answer 16

SrSO4

Question 17

what is the ionic formula for Iron (III) Hydrogencarbonate

Answer 17

Fe(HCO3)3

Question 18

name the ionic compound: Al2(CO3)3

Answer 18

Aluminium Carbonate

Question 19

name the ionic compound: Fe2(CO3)3

Answer 19

Iron (III) Carbonate

Question 20

name the ionic compound: TiO2

Answer 20

Titanium Dioxide or Titanium (IV) Oxide

Question 21

Which polymer has hydrogen bonding between the polymer chains?

Answer 21

kevlar

Question 22

The melting point of XeF4 is higher than the melting point of PF3
Explain why the melting points of these two compounds are different.
In your answer you should give the shape of each molecule, explain why each molecule has that shape and how the shape influences the forces that affect the melting point.

Answer 22

• XeF4 4BP and 2LP around Xe
• PF3 3BP and 1LP around P
• XeF4 is square planar
• PF3 is pyramidal (allow tetrahedral)
• Electron pairs repel as far as possible or Lone pair repels more than bonding pairs
• XeF4 has vdw forces and PF3 has dipole-dipole forces (and vdw)
• Stronger/more intermolecular forces in XeF Due to larger Mr or more electrons or larger molecules or packs more closely

Question 23

Fluoroantimonic acid contains two ions, SbF6– and H2F+ Draw the shape of the SbF6–ion and the shape of the H2F+
ion. Include any lone pairs that influence the shape. Name the shape of each ion.

Answer 23

Question 24

Draw a diagram to show the strongest type of interaction between two molecules of ethanol (C2H5OH) in the liquid phase. Include all lone pairs and partial charges in your diagram.

Answer 24

Question 25

Which statement about barium sulfate is correct? A It is soluble in water at a temperature of 100 °C. B It is used in medicine because it does not dissolve in body fluids. C It is a pale yellow solid. D It reacts with acidified barium chloride solution.

Answer 25

B

Question 26

Explain why the second ionisation energy of calcium is lower than the second ionisation energy of potassium.

Answer 26

- In Ca+ outer electron is further from nucleus and from a higher (energy) orbital - more shielding in Ca+

Question 27

A student added 6 cm3 of 0.25 mol dm–3 barium chloride solution to 8 cm3 of 0.15 mol dm–3 sodium sulfate solution. The student filtered off the precipitate and collected the filtrate. Give an ionic equation for the formation of the precipitate. Show by calculation which reagent is in excess. Calculate the total volume of the other reagent which should be used by the student so that the filtrate contains only one solute.

Answer 27

1. Ba2+ + SO42– → BaSO4 2. n BaCl2 (6/1000 × 0.25) = 1.5 × 10–3 and n Na2SO4 = (8/1000 × 0.15) = 1.2× 10–3 so BaCl2 in excess 3. 10 cm3 (of 0.15 mol dm–3 sodium sulfate)