OZ.a-u - The Ozone story | OZ1-8 |
OZ.Q Exam questions from past papers
Earth or sun’s energy (solar energy)
The ‘sun’ may not be allowed in this
Some haloalkanes act as greenhouse gases that case
absorb infrared radiation in the troposphere.
Give the source of this infrared radiation. (1)?
● E=hf
● En x NA = EN
● EN / 1000 = EN
● 1.25x10 x 6.63x10-34 = 8.29x10-
19
● (8.29x10-) x 6.02x1023
One frequency absorbed by ozone is 1.25x1015 Hz = 499 kJmol-1
Calculate the enthalpy of the strongest bond that can ● (hxfxNA / 1000)
be broken by this frequency?
Infrared radiation
Name the type of EMR that is emitted from the Earth
surface
Some students set out to investigate the rate of ● Quench the solution taking
hydrolysis of 1-bromobutane. They mix 1-bromobutane certain volume of solution at set
with sodium hydroxide solution and measure the conc intervals of time (1)
of hydroxide ions after certain times at 51 degrees? ● Cool down the samples in ice
water (1)
Suggest the procedure the students use to follow the ● Do a titration for each sample to
reaction? (3) and how did they maintain the temperature find the concentration of
at 51 degrees (1) hydroxide ions (1)
● By using a water bath
, ● C
● (As iodoethane the molecule has
overall more electrons and a
bigger sized molecule than
Fluoroethane -> stronger id-id
forces -> stronger attraction ->
higher bp)
● The id-id forces of the overall
Which statement correctly describes the boiling points molecule would have a greater
of fluoroethane and iodoethane? effect on bp than the pd-pd
forces of the C- halogen bond
Both oxygen and chlorine atoms react with ozone in the Role of oxygen
stratosphere. ● Oxygen atoms/radicals react
Describe and compare the roles of oxygen and chlorine with ozone
atoms in the breakdown of ozone and their relative ● O + O3 -> 2O2
effects. Include equations where appropriate. (6) Role of chlorine
● Chlorine radicals react with
ozone
● Cl + O3 -> ClO + O2
● ClO reacts with oxygen atoms
regenerating the chlorine radical
● ClO + O -> Cl + O2
● Overall reaction is the removal
of ozone
● O + O3 -> 2O2
● The chlorine radical is in a
catalytic cycle
Comparison of relative effects
● One O atom can only remove
one ozone molecule
● One Cl atom can remove many
ozone molecules
OZ.a-d - Bonding & Structure | OZ6 | OZ7 |
What are CFCs, what are they used as and ● Chlorofluorocarbons (thus containing only carbon,
why? chlorine, and fluorine)
● Use as propellants, aerosols and refrigerants
because they were non toxic, not flammable and
not reactive
Define electronegativity? The ability of an atom to attract electrons (1) in a covalent
bond (1) towards itself
What is a dipole? An uneven distribution of charge
OZ.Q Exam questions from past papers
Earth or sun’s energy (solar energy)
The ‘sun’ may not be allowed in this
Some haloalkanes act as greenhouse gases that case
absorb infrared radiation in the troposphere.
Give the source of this infrared radiation. (1)?
● E=hf
● En x NA = EN
● EN / 1000 = EN
● 1.25x10 x 6.63x10-34 = 8.29x10-
19
● (8.29x10-) x 6.02x1023
One frequency absorbed by ozone is 1.25x1015 Hz = 499 kJmol-1
Calculate the enthalpy of the strongest bond that can ● (hxfxNA / 1000)
be broken by this frequency?
Infrared radiation
Name the type of EMR that is emitted from the Earth
surface
Some students set out to investigate the rate of ● Quench the solution taking
hydrolysis of 1-bromobutane. They mix 1-bromobutane certain volume of solution at set
with sodium hydroxide solution and measure the conc intervals of time (1)
of hydroxide ions after certain times at 51 degrees? ● Cool down the samples in ice
water (1)
Suggest the procedure the students use to follow the ● Do a titration for each sample to
reaction? (3) and how did they maintain the temperature find the concentration of
at 51 degrees (1) hydroxide ions (1)
● By using a water bath
, ● C
● (As iodoethane the molecule has
overall more electrons and a
bigger sized molecule than
Fluoroethane -> stronger id-id
forces -> stronger attraction ->
higher bp)
● The id-id forces of the overall
Which statement correctly describes the boiling points molecule would have a greater
of fluoroethane and iodoethane? effect on bp than the pd-pd
forces of the C- halogen bond
Both oxygen and chlorine atoms react with ozone in the Role of oxygen
stratosphere. ● Oxygen atoms/radicals react
Describe and compare the roles of oxygen and chlorine with ozone
atoms in the breakdown of ozone and their relative ● O + O3 -> 2O2
effects. Include equations where appropriate. (6) Role of chlorine
● Chlorine radicals react with
ozone
● Cl + O3 -> ClO + O2
● ClO reacts with oxygen atoms
regenerating the chlorine radical
● ClO + O -> Cl + O2
● Overall reaction is the removal
of ozone
● O + O3 -> 2O2
● The chlorine radical is in a
catalytic cycle
Comparison of relative effects
● One O atom can only remove
one ozone molecule
● One Cl atom can remove many
ozone molecules
OZ.a-d - Bonding & Structure | OZ6 | OZ7 |
What are CFCs, what are they used as and ● Chlorofluorocarbons (thus containing only carbon,
why? chlorine, and fluorine)
● Use as propellants, aerosols and refrigerants
because they were non toxic, not flammable and
not reactive
Define electronegativity? The ability of an atom to attract electrons (1) in a covalent
bond (1) towards itself
What is a dipole? An uneven distribution of charge
