AQA A-level Chemistry 'Unit 5 (CHEM5)' Revision

Comprehensive revision notes for the AQA's specification of Chemistry Unit 5 (CHEM5).

Pages in this set

Page 1

Preview of page 1
· Explain two ways of improving the reliability of results obtained from titration of a sample of
water from a polluted river
· Repeat titration until concordant results, average concordant results
· Analyse several samples from different areas of the river

Thermodynamics
· Explain why the enthalpy of vaporisation of…

Page 2

Preview of page 2
from one mole of gaseous 1+ ions to form one mole of gaseous 2+ ions

Page 3

Preview of page 3
and · State the definition of the first electron affinity H
ea1

second electron affinity H
ea2

· First electron affinity is the enthalpy change when one mole of electrons is added to one mole
of gaseous atoms to form one mole of gaseous 1- ions
· Second electron affinity…

Page 4

Preview of page 4
(s)

+F
2(g)

CaF
2(s)

· State the definition and equation for the standard enthalpy of atomisation H
at

of S
· Enthalpy change when one mole of gaseous S atoms is formed from its element
· With the element in its standard state
·S
(s)

S
(g)

· State…

Page 5

Preview of page 5

Page 6

Preview of page 6
of · State the definition and equation for the first electron affinity H
ea1

Cl and second electron affinity
H
ea2

of S
· First electron affinity is the enthalpy change when one mole of electrons is added to one mole
of gaseous Cl atoms to form one mole of…

Page 7

Preview of page 7
2(s)

· Enthalpy of lattice dissociation is the enthalpy change when one mole of CaF
2

is separated into its
gaseous ions
· CaF
2(s)

Ca2+
(g)

+ 2F-
(g)

· State the definition and equation for the enthalpy of hydration H
hyd

of F and enthalpy of solution H…

Page 8

Preview of page 8
K+
(aq)

+ NO
3
-
(aq)

· Explain why the first electron affinity of O is an exothermic process whereas the second
electron affinity of O is an endothermic process
· First electron affinity is attraction between electron added and nucleus
· Second electron affinity is repulsion between electron…

Page 9

Preview of page 9
is · Explain why the mean bond dissociation enthalpy of Cl
2

greater than the mean bond dissociation
enthalpy of Br
2

· Bond is shorter, bonding pair of electrons is close to nucleus
· Stronger attraction between bonding pair of electrons and nucleus
· Explain why the second ionisation…

Page 10

Preview of page 10
and Cl- ions
· Explain why the enthalpy of hydration of Cl- is greater than the enthalpy of hydration of Br-
· Cl- ion has a smaller size, greater charge density than Br- ion
· Stronger electrostatic forces of attraction between negatively-charged Cl- ions and the
electron-deficient H+ of water,…

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »

AQA A-level Chemistry 'Unit 5 (CHEM5)' Revision

Comprehensive revision notes for the AQA's specification of Chemistry Unit 5 (CHEM5).

Pages in this set

Page 1

Preview of page 1
· Explain two ways of improving the reliability of results obtained from titration of a sample of
water from a polluted river
· Repeat titration until concordant results, average concordant results
· Analyse several samples from different areas of the river

Thermodynamics
· Explain why the enthalpy of vaporisation of…

Page 2

Preview of page 2
from one mole of gaseous 1+ ions to form one mole of gaseous 2+ ions

Page 3

Preview of page 3
and · State the definition of the first electron affinity H
ea1

second electron affinity H
ea2

· First electron affinity is the enthalpy change when one mole of electrons is added to one mole
of gaseous atoms to form one mole of gaseous 1- ions
· Second electron affinity…

Page 4

Preview of page 4
(s)

+F
2(g)

CaF
2(s)

· State the definition and equation for the standard enthalpy of atomisation H
at

of S
· Enthalpy change when one mole of gaseous S atoms is formed from its element
· With the element in its standard state
·S
(s)

S
(g)

· State…

Page 5

Preview of page 5

Page 6

Preview of page 6
of · State the definition and equation for the first electron affinity H
ea1

Cl and second electron affinity
H
ea2

of S
· First electron affinity is the enthalpy change when one mole of electrons is added to one mole
of gaseous Cl atoms to form one mole of…

Page 7

Preview of page 7
2(s)

· Enthalpy of lattice dissociation is the enthalpy change when one mole of CaF
2

is separated into its
gaseous ions
· CaF
2(s)

Ca2+
(g)

+ 2F-
(g)

· State the definition and equation for the enthalpy of hydration H
hyd

of F and enthalpy of solution H…

Page 8

Preview of page 8
K+
(aq)

+ NO
3
-
(aq)

· Explain why the first electron affinity of O is an exothermic process whereas the second
electron affinity of O is an endothermic process
· First electron affinity is attraction between electron added and nucleus
· Second electron affinity is repulsion between electron…

Page 9

Preview of page 9
is · Explain why the mean bond dissociation enthalpy of Cl
2

greater than the mean bond dissociation
enthalpy of Br
2

· Bond is shorter, bonding pair of electrons is close to nucleus
· Stronger attraction between bonding pair of electrons and nucleus
· Explain why the second ionisation…

Page 10

Preview of page 10
and Cl- ions
· Explain why the enthalpy of hydration of Cl- is greater than the enthalpy of hydration of Br-
· Cl- ion has a smaller size, greater charge density than Br- ion
· Stronger electrostatic forces of attraction between negatively-charged Cl- ions and the
electron-deficient H+ of water,…

Comments

No comments have yet been made