NCEA Level 1 Chemistry (90173) 2010 — page 1 of 3
Assessment Schedule – 2010
Chemistry: Describe selected non-metals and their compounds (90173)
Evidence Statement
Q
Evidence
ONE
(a)(i)
(ii)
Achievement
THREE of:
The Contact Process
 Names the
process.
Combustion is the burning of Sulfur in
oxygen.
Hydration is the adding of water to the
oleum.
 Describes a
process.
S + O2  SO2
H2S2O7(l) + H2O(l)  2 H2SO4(l)
(iii)
(b)
Vanadium pentoxide (V2O5) is the catalyst
used during the conversion of SO2 to SO3. A
catalyst speeds up a reaction and it is needed
here because otherwise the process is too
slow to be economically viable.
Phosphate rock is insoluble but
superphosphate has more solubility in water.
(This is important for fertiliser to dissolve
into soil and be absorbed by plants.)
Sulfuric acid is added to phosphate rock (in
superphosphate manufacture process) so as to
improve solubility in water.
Calcium phosphate + sulfuric acid
calcium dihydrogen phosphate +
calcium sulfate
Ca3(PO4)2(aq) + 2H2SO4() 
Ca(H2PO4)2(s) + 2CaSO4(s)
Phosphate rock grinding is to get enough
phosphate concentration to make the
superphosphate because it increases surface
area.
Granulation process is done to give
superphosphate the desired physical
properties by forming them into granules of
desirable size that are easier to handle and
release phosphate at an even rate.
Achievement with
Merit
Achievement
with Excellence
FOUR of:
FOUR of:
(including at least
one set of
equations)
 Explains ONE
of combustion
or hydration
steps.
 Explains
combustion
and hydration
with TWO
correct
equations.
 ONE correct
equation for
combustion or
hydration step.
 Names the catalyst
used.
 Links named
catalyst to
reason for use.
 Discusses
named
catalyst’s role
in this process.
 Recognises
insoluble property
of phosphate rock.
 Links
insolubility of
phosphate rock
to the need to
add sulfuric
acid.
 States the
importance of
rock grinding.
 Identified
chemicals of
superphosphate.
 Explains
importance of
granulation OR
rock grinding
for desirable
physical /
chemical
properties.
 Applies
addition of
sulfuric acid to
improve
solubility of
superphosphate
enabling its
role as a
fertiliser.
 THREE formulae
correct.
 Word equation
is correct.
 All formulae
correct.
 Discusses
importance of
granulation
AND grinding
to chemical and
physical
properties
needed to
produce
superphosphate.
 Equation is
correctly
balanced.
NCEA Level 1 Chemistry (90173) 2010 – page 2 of 3
TWO
• The action of UV light on oxygen in air
forms ozone O3.
• Ozone O3 is formed by the interaction of
nitrogen oxides with oxygen in the air.
• Equation 3O2  2O3 in the presence of
UV light. (The answer must mention UV
light if writing equation.)
• Lightning strikes.
TWO of:
THREE of:
 Describes a
process showing
how ozone is
formed.
 Explains a
process
showing how
ozone is
formed.
The ozone layer filters out harmful UV
radiation from the sun.
Explains a process
showing how
ozone is formed.
 Explains the
role of ozone
for protection.
AND
Explains the role
of ozone for
protection.
Ozone depleting gases contain chlorine and
bromine atoms. Examples include:
• Man-made chemicals like
chlorofluorocarbons (CFCs) and
hydrochlorofluorocarbons (HCFCs), –
human-produced gases once used in almost
all refrigeration and air conditioning
systems.
• Halons found in fire extinguishers also
contain bromine atoms. Methyl bromide,
carbon tetrachloride, methyl chloroform.
 States ONE ozone
depleting factor.
 Links named
ozone depleting
chemical to
man-made use.
AND
Links named
ozone depleting
chemicals to manmade use.
Ozone depletion means that harmful UV
radiation will reach the earth’s surface
possibly causing:
• Humans – increased skin cancer rates
aging of skin or cataracts in eyes.
• Plants – less growth as the increased rays
can burn the plants / decreased
photosynthesis as the increased rays can
damage the cells that produce chlorophyll
or carry out photosynthesis.
• Animals – decreased phytoplankton
productivity (marine foodweb), due to their
sensitivity to the rays.
• More radiation, more warming of the
Earth.
 States ONE effect
of ozone
depletion.
 Explains ONE
effect of ozone
depletion.
AND
Explains TWO
effects of ozone
depletion.
THREE
(a)
The chlorine reacts with the water to form an
acidic solution.
Cl2(g) + H2O()  HCl(aq) + HOCl(aq)
Recognises that
chlorine in water
forms an acidic
solution.
(b)
Chlorine kills bacteria through a fairly simple
chemical reaction. The hypochlorous acid
(HOCl) and hypochlorite ion (OCl–) kill
microorganisms and bacteria by attacking the
cell wall and destroying the enzymes and
structures inside the cell, rendering them
oxidised and harmless (act as a disinfectant).
TWO of:
 Recognises that
chlorine in water
forms an acidic
solution.
(c)
HOCl and OCl– either combine with another
chemical, such as ammonia, or are broken
down into single atoms. Both of these
processes render the chlorine harmless.
Sunlight speeds these processes up. You
have to keep adding chlorine to the pool as it
breaks down.
AND
Describes ability to
act as oxidant /
disinfectant on
bacteria.
 Writes balanced
equation. (States
not required).
 Links formation
of HOCl to
ability to act as
disinfectant /
oxidant.
 Recognises that
Cl2 continually
reacts and HOCl
breaks down and
needs replacing.
Writes balanced
equation (states
not required)
AND
Links to acidic
nature of solution,
AND
Links formation
of HOCl to
detailed outline of
its action on
bacteria,
AND
Cl2 continually
reacts and HOCl
breaks down and
needs replacing.
NCEA Level 1 Chemistry (90173) 2010 – page 3 of 3
FOUR
(a)
(b)
Motor vehicles produce exhaust gases
containing oxides of nitrogen such as
nitrogen dioxide (NO2) and nitric oxide
(NO). OR Forms when reacted with O2 in
lightning strikes.
The mixture of nitric oxide (NO) and
nitrogen dioxide (NO2) is sometimes referred
to as NOx.
When sunlight acts on NOx, photochemical
smog can be formed.
People:
• irritate respiratory tract / respiratory
disease
• increases eye, nose and throat infections
• causes headaches
• unconsciousness
• death.
Environment:
• inhibits plant growth / damages leaves
• degrades plastics
• visual pollution
• acid rain.
Properties of smog:
• poisonous gases, NO2 (and others), slowly
poison living things
• primary pollutants can go on to cause
secondary pollutants O3 (causes breathing
difficulties, headaches, fatigue and can
aggravate respiratory problems). NO2 and
PAN
• the peroxyacetylnitrate (CH3CO–OO–NO2)
in photochemical smog can irritate the
eyes, causing them to water and sting.
• these can cause acid rain
• smog blocking sunlight.
Describes source of
NOx
Links source of
NOx to formation
of named particles
in photochemical
smog / importance
of sunlight in
formation.
Discusses
reactions of NOx
and sunlight in
forming
photochemical
smog.
AND
Describes TWO
effects of
photochemical smog.
AND
Links properties of
smog to TWO
effects on health
AND / OR
environment.
AND
Discusses
properties of smog
with respect to
TWO effects on
health AND
environment.
Judgement Statement
Achievement
Achievement with Merit
Achievement with Excellence
3A
OR
2M
3M
OR
1E+1M+1A
2E+1A