STAGE 2 CHEMISTRY
ASSESSMENT TYPE 1: Investigations Folio
Practical Investigation: Preparation of an Ester
Response 2
Skills checklist (Teacher record)
Part A:
Evidence shown:
Performing reflux
Correctly set up and conducted. Took a very long time.
Use of separating funnel
Pointed towards partner when releasing gas.
Performing distillation
Clamped correctly and no strain evident. Thermometer
placed correctly. Took a very long time to set up.
Clarity of ester product
Clear.
Area cleanliness
Somewhat disorganised – condenser tubing tangled
around retort.
Safe conduct
Worked safely but unaware of untied shoe-laces.
Cooperation
Tended to wait for partner to give directions.
Investigation
Manipulates
apparatus
carefully and
mostly effectively
to implement
organised safe
and ethical
investigation
procedures.
Application
Applies generally
constructive
individual and
collaborative
work skills.
Other
Student Report
Discussion
The ester boiled at 139 - 143C and had a clear and sweet odour.
The equation is
CH3COOH + CH3CH2CH2CH2CH2-OH
CH3COO CH3CH2CH2CH2CH2 + H2O
pentanyl ethanoate
Reflux is when you boil everything for a long time without anything evaporating.
At the end of the reaction the ester has to be seperated from the rest of the mixture in the
flask so its washed with water because the ester ie insoluable in water but the water
formed in the reaction is soluable. There are some reactants present in the mixture as
well that could dissolve in the water so that they can be removed too because a separate
layer fomrs with the ester and the water layer can be collected leaving the ester behind.
There are acids in the mixture and so NaCO3 is added to react with these. You can see
that there is an acid because when the NaCO3 was added there were bubble.
NaCO3 + H2SO4  CO2 + H2O + NaSO4
Page 1 of 4
Stage 2 Chemistry annotated response
Ref: A107549 (revised January 2013)
© SACE Board of South Australia 2013
Application
Attempts to use
chemical terms,
conventions,
formulae, and
equations.
Some incorrect
formulae,
equations, and
terms used.
Then we washed with water again to clean away anything that was still left that was water
soluable. CaCl2 reacts with any water that is left over. The last step was distillation and
this is done when you have to seperate substances that have different boiling points
because then they boil at different temperatures and can be collected seperately. The
ester boiled last. The boiling point was fairly accurate and the etser was clear so our
isolation worked well and there were no systematic errors and we got an accurate result.
There was a poor yield because the reaction was reversable and some of the products
decomposed back to the reactants again. This was because it was an equilibrium. You
could improve the yield if you reflux for a longer time so that more reactants will go to
products or you could start off with more of one of the reactants so that more product
forms (LCP). You could improve the purity of the ester by doing the prac more carefully so
that there are less random errors and the boiling point will have less scatter but our result
was quite accurate as the boiling point was quite near the true value, but you could do the
distillation again to get a higher boiling point.
This prac had a lot of hazards. We made sure that we wore aprons and safety glasses
and heated the flask with a tiny flame and watched it carefully all the time to make sure it
didn’t boil over. Lots of gas was formed by CO2 in the separating tube and it could
explode so we opened the tap to let it out.
We were an OK group, but my partner was a bit bossy and tended to take over things.
They didn’t always work out so it took us a while to set up the glassware. I work better
with someone more like me. Perhaps I should of stood up for myself but it was easier just
to let my partner decide what to do. I thought that we should use the small Bunsen but my
partner said that it was the big Bunsen but I was right. Probably we would of worked
better if we had read the prac more carefully. But we got a good product so I suppose we
were a good group.
Additional Comments
More than one assessment will need to be considered to assess ability to:
 use appropriate chemical terms, conventions, formulae and equations highly effectively (A grade descriptor)
 communicate knowledge and understanding highly effectively in different formats (A grade descriptor).
Knowledge and Understanding
 Communicates basic information.
Page 2 of 4
Stage 2 Chemistry annotated response
Ref: A107549 (revised January 2013)
© SACE Board of South Australia 2013
Analysis and
Evaluation
Limited evaluation
of some
procedures.
Identifies some
improvements
that are generally
appropriate.
Performance Standards for Stage 2 Chemistry – Practical Investigation: Preparation of an Ester
A
Investigation
Analysis and
Evaluation
Application
Knowledge and
Understanding
Designs logical, coherent, and
detailed chemistry investigations.
Critically and systematically
analyses data and their
connections with concepts, to
formulate logical and perceptive
conclusions and make relevant
predictions.
Applies chemistry concepts and
evidence from investigations to
suggest solutions to complex
problems in new and familiar
contexts.
Consistently demonstrates a deep
and broad knowledge and
understanding of a range of
chemistry concepts.
Critically and logically selects
and consistently and
appropriately acknowledges
information about chemistry and
issues in chemistry from a range
of sources.
Manipulates apparatus and
technological tools carefully and
highly effectively to implement
well-organised safe and ethical
investigation procedures.
Critically and logically evaluates
procedures and suggests a
range of appropriate
improvements.
Uses appropriate chemical
terms, conventions, formulae,
and equations highly effectively.
Uses knowledge of chemistry
perceptively and logically to
understand and explain social or
environmental issues.
Demonstrates initiative in
applying constructive and
focused individual and
collaborative work skills.
Uses a variety of formats to
communicate knowledge and
understanding of chemistry
coherently and highly effectively.
Applies chemistry concepts and
evidence from investigations to
suggest solutions to problems in
new and familiar contexts.
Demonstrates some depth and
breadth of knowledge and
understanding of a range of
chemistry concepts.
Uses appropriate chemical
terms, conventions, formulae,
and equations effectively.
Uses knowledge of chemistry
logically to understand and
explain social or environmental
issues.
Obtains, records, and displays
findings of investigations using
appropriate conventions and
formats accurately and highly
effectively.
B
Designs well-considered and
clear chemistry investigations.
Logically selects and
appropriately acknowledges
information about chemistry and
issues in chemistry from different
sources.
Manipulates apparatus and
technological tools carefully and
mostly effectively to implement
organised safe and ethical
investigation procedures.
Clearly and logically analyses
data and their connections with
concepts, to formulate
consistent conclusions and
make mostly relevant
predictions.
Logically evaluates procedures
and suggests some appropriate
improvements.
Applies mostly constructive and
focused individual and
collaborative work skills.
Uses a variety of formats to
communicate knowledge and
understanding of chemistry
coherently and effectively.
Obtains, records, and displays
findings of investigations using
appropriate conventions and
formats mostly accurately and
effectively.
C
Designs considered and
generally clear chemistry
investigations.
Selects with some focus, and
mostly appropriately
acknowledges, information about
chemistry and issues in
chemistry from different sources.
Manipulates apparatus and
technological tools generally
carefully and effectively to
implement safe and ethical
investigation procedures.
Analyses data and their
connections with concepts, to
formulate generally appropriate
conclusions and make simple
predictions, with some
relevance.
Evaluates some procedures in
chemistry and suggests some
improvements that are
generally appropriate.
Applies chemistry concepts and
evidence from investigations to
suggest some solutions to basic
problems in new or familiar
contexts.
Uses generally appropriate
chemical terms, conventions,
formulae, and equations with
some general effectiveness.
Applies generally constructive
individual and collaborative
work skills.
Demonstrates knowledge and
understanding of a general range
of chemistry concepts.
Uses knowledge of chemistry with
some logic to understand and
explain one or more social or
environmental issues.
Uses different formats to
communicate knowledge and
understanding of chemistry with
some general effectiveness.
Obtains, records, and displays
findings of investigations using
generally appropriate
conventions and formats with
some errors but generally
accurately and effectively.
Page 3 of 4
Stage 2 Chemistry annotated response
Ref: A107549 (revised January 2013)
© SACE Board of South Australia 2013
D
Investigation
Analysis and
Evaluation
Application
Knowledge and
Understanding
Prepares the outline of one or
more chemistry investigations.
Describes basic connections
between some data and
concepts, and attempts to
formulate a conclusion and
make a simple prediction that
may be relevant.
Applies some evidence to
describe some basic problems
and identify one or more simple
solutions, in familiar contexts.
Demonstrates some basic
knowledge and partial
understanding of chemistry
concepts.
Attempts to use some chemical
terms, conventions, formulae,
and equations that may be
appropriate.
Identifies and explains some
chemistry information that is
relevant to one or more social or
environmental issues.
Attempts individual work
inconsistently, and contributes
superficially to aspects of
collaborative work.
Communicates basic information
to others using one or more
formats.
Identifies a basic problem and
attempts to identify a solution in
a familiar context.
Demonstrates some limited
recognition and awareness of
chemistry concepts.
Identifies some chemical terms
or formulae.
Shows an emerging
understanding that some
chemistry information is relevant
to social or environmental issues.
Selects and may partly
acknowledge one or more
sources of information about
chemistry or an issue in
chemistry.
Uses apparatus and
technological tools with
inconsistent care and
effectiveness and attempts to
implement safe and ethical
investigation procedures.
For some procedures, identifies
improvements that may be
made.
Obtains, records, and displays
findings of investigations using
conventions and formats
inconsistently, with occasional
accuracy and effectiveness.
E
Identifies a simple procedure for
a chemistry investigation.
Identifies a source of information
about chemistry or an issue in
chemistry.
Attempts to use apparatus and
technological tools with limited
effectiveness or attention to safe
or ethical investigation
procedures.
Attempts to connect data with
concepts, formulate a
conclusion, and make a
prediction.
Acknowledges the need for
improvements in one or more
procedures.
Shows emerging skills in
individual and collaborative
work.
Attempts to communicate
information about chemistry.
Attempts to record and display
some descriptive information
about an investigation, with
limited accuracy or effectiveness.
Page 4 of 4
Stage 2 Chemistry annotated response
Ref: A107549 (revised January 2013)
© SACE Board of South Australia 2013